Below is the text version of the webinar, DOE Zero Energy Ready Home - Comprehensive Building Science, presented in March 2014. Watch the presentation.
Hi, everyone. Thanks for joining us for the Department of Energy Challenge Home technical webinar. We'll be starting in a couple minutes. Waiting for people to come on in.
Hi, everyone. We're just waiting for a couple minutes while people trickle in. Thanks for joining in. We'll be right with you.
Hi, everyone. My name is Lindsay Parker. I want to welcome you to the U.S. Department of Energy Challenge Home technical webinar series. We're excited that you could all join us today. I'm going to give you a short introduction on today's session, which is on comprehensive building science with our presenter Dean Gamble from U.S. EPA Energy Star program. This is part of a continuing series of technical training webinars to support our partners in designing and building Department of Energy Challenge Homes. So just a couple of housekeeping issues: We'll have all attendees in listen- only mode, and feel free to ask questions using the question section in the GoToMeeting panel. As many of you, we'll cover as many of your questions as possible near the end of the webinar. And we'll be recording this webinar, as well. And we'll post it to the DOE Challenge Home resources website soon after. So right now I'm going to hand it over to Sam Rashkin, chief architect of the U.S. Department of Energy.
Hey, welcome, everyone, and thanks for attending this webinar today.
Slide 1: As many of you may know, we travel around the country doing DOE Challenge Home training seminars where we present the depth and breadth of the Challenge Home program and the business case through all the specifications it takes to achieve zero-energy-ready performance. What we promise our attendees in our training classes is that we provide more detailed level presentation and discussion about the program specifications through these webinars, and that's what we're here for today. The foundation for DOE Challenge Home, which by the way, will be changing its name soon to the DOE Zero Energy Ready Home, the foundation for the DOE Challenge Home is that all homes must first be certified as EPA Energy Star. And Energy Star Certified Homes are so important because they make sure that we have a comprehensive building science with each and every certified Challenge Home. So today we're going to learn about all the requirements of the Energy Star Certified Home program and what it takes to do complete building science to meet their requirements. We're lucky enough to have a good friend and colleague from my days at EPA, Dean Gamble. He was at that time a contractor working for ICF. He's trained in architectural engineering. He's an amazing guy both in terms of his technical skills, and his presentation skills, and he's incredibly thoughtful, making sure all the issues we had putting Energy Star version 3 together. So you have the best source for this content. And I'm going to hand it off to Dean Gamble.
Hi, Sam. I appreciate that. I tried to tell you to sell me low, set a lot bar for this presentation. Now you've done the opposite, so I hope I can live up to it. I think ...
Can I interrupt? (audio loss) ... I think that all the attendees ...
The broadcast is starting. All attendees are in listen-only mode.
So sorry for that, guys. So we had a couple of technical difficulties, but now everyone's on the line, and I hope everyone can see us. If not, feel free to mention so in our question block in the GoToMeeting panel. Hi, everyone. Welcome to the Department of Energy Challenge Home technical webinar series. My name is Lindsay Parker. I'll be covering some housekeeping issues here today before I hand it off to Sam Rashkin and our presenter. So welcome to the series. We're so glad that you could join us today. Our session is going to cover comprehensive building science. Our technical series is part of our webinar series to support our partners in designing and building Department of Energy Challenge Homes. So just a couple of housekeeping issues: Everyone will be in listen-only mode. But feel free to ask questions, and we'll cover as many of those at the end of the webinar as we can. And we'll also be checking in every now and then to see if there are any questions that we can answer along the way. This webinar is being recorded and it will be posted on our Challenge Home resources website after the webinar. So be on the lookout for an email with the follow-up information about that. So please be on the lookout for an email with some follow-up information on that. And I'm going to hand it over to the chief architect of the Department of Energy, Sam Rashkin.
Slide 1: Hey, thank-you, Lindsay, and welcome everybody to the webinar today. I want to first just tee up what this is about, why this particular one is so important. DOE Challenge Home is basically a zero energy ready home label, and in fact our program name is changing to the DOE Zero Energy Ready Home. As most people may know, the underpinning for this label certification is Energy Star Certified Homes. In other words, you can't even begin to do Challenge Home until you do the Energy Star Certified Home requirements. So this is critical to get the comprehensive building science ensured in every home that earns our label. So today we're lucky enough to have the technical director for EPA's Energy Star Cerified Home program, Dean Gamble. He's a friend and colleague from my days when I was at EPA. He used to work for ICF Consulting at that time as a consultant. He comes from Penn State Architectural Engineering Program. He's an incredibly talented individual who has amazing insights both technically and in thinking through the program's ability to work with the industry and many friends. He's just invaluable for developing this program's specifications. So you have the best source for this content. I'm going to hand it off to Dean Gamble now.
Slide 2: Dean, are you on?
Hey we're sorry for the little gap and silence here. We're concerned that Dean Gamble ...
Can you guys hear me now?
Yes, we can.
Oh, good. Alright. Not sure what happened there. That is odd. Well, the best of technology at work here. Feels like inevitably these things happen only when you're actually doing the presentation. So let's go ahead and get started. I'll move right along. I told you that Sam had set the bar too high. That's what I was trying to say before I was muted. Obviously he did. Alright, so today we're going to be talking about the building science basics behind Energy Star.
Slide 3: I just want to provide a little bit of context first. So the Energy Star Certified Homes program used to be mostly about mixing and matching components, sort of like a salad bar. And that was nothing to sneeze at. And you don't want to sneeze at a salad bar, so I think that's a good thing. Hopefully you enjoyed that little joke, because that's as good as it's going to get for the rest of the presentation. Now homes that were built with the mix and match approach had some great features that really moved the industry forward. So these are things like tight ducts and the tight enclosure and third-party vertification. But with version 3, we're offering what we think is a lot more than a salad bar. We're saying that there are three systems that you have to get right in every certified home.
Slide 4: And this is just like a high-performance new car. So maybe the car is promising 200 miles per hour per gallon, plus it has a fancy navigation system and seat warmers and despite all these great features, you still really need critical systems to be working, too. Like the braking system. So Toyotoa got into a little trouble a few years back with high-efficiency cars that occasionally had faulty brakes. More recently, people have found that while GM may be building great cars, their ignition systems leave something to be desired. And so how appealing are these cars to consumers? You know, probably not very appealing at all, despite all these other advanced systems. You really need to have these critical components in place. So you can maybe see how high-performance new homes are not going to be super-successful in the marketplace either, if they don't get the fundamentals right.
Slide 5: So that brings us to the two key components of the Energy Star program. Which hopefully many of you recognize by now. The first is an efficiency target and the second is four mandatory inspection checklists. Now, the efficiency target is about 15 percent better than the 2009 IACC in most states. Partners can either use a prescriptive set of measures or a performance approach to mix and match upgrades until they hit that target. The second component is the four inspection checklists. They help ensure that three critical systems are delivered in each home: The thermal enclosure system, the HVAC system, and the water management system. And today we're going to be focusing on the second key component. This is where a lot of the building science basics lie.
Slide 6: That actually brings me to my first poll question before we dive into the details. So I'd like to ask those on the phone, which of the following programs do you have experience certifying homes under? And you can list the most stringent of the programs that you've participated in. If you've only done Energy Star before, select A.
Slide 7: If you've done Energy Star plus Challenge Home, then you can select B. And if you've done those plus Passive House PHIUS +, then pick C. If you haven't done any of them, you can leave it blank.
Let's see. I think Lindsay's going to conduct a poll on this end, on her end. Let's hold on for a second to see if that pops up. If we can't get that to work, then we'll have us proceed.
Dean, the poll's going.
42 percent of people voted. Waiting a couple of seconds before everyone gets there.
OK. People are thinking it through pretty carefully.
Alright. Closing the poll now.
And do you need me to return the presentation to you, or can you do that from your end?
Slide 8: We got it from here.
Now I'm sharing the poll results. 87 percent have chosen Energy Star, 10 percent chose Challenge Home, and 4 percent have chosen PHIUS.
OK, great. So that gives me a little bit of context. So a lot of you already do have some experience with Energy Star which is really encouraging. And it sounds like a number of you have already ventured into the Challenge Home territory. Even some of you have gone into PHIUS, so that's great, as well.
Slide 9: OK. So let's go ahead and dive into these actual systems and the building science underlying them. So the first system that you need to get right is the thermal enclosure system. Now why is this important? It's because a well-insulated and air-sealed home with good windows and doors reduces the amount of energy needed to keep the home comfortable. A home without these things will cost more money to keep the home comfortable. In some cases it won't even be possible to keep it comfortable regardless of the money that you're spending on utility bills. Which is sort of like my home. So that's why we have the thermal enclosure system rater checklist, to help ensure that every certified home has a complete thermal enclosure system.
Slide 10: And there are really just two building science basics you need to know to understand why this system is so important. So the first is that energy moves from more to less. So here we're talking about heat moving from a hotter space to a cooler space, which is not so difficult. So think of a cooler. You have your food and your beverages in there for a tailgate, and you fill it with ice. So if it starts at 40 degrees, and it's 90 degrees outside the cooler, then heat or energy will move into that cooler from more to less. And over time, that cooler will eventually warm up to 90 degrees. And this will happen every single time.
Slide 11: So now let's apply this to an actual house. Assume that a family's on vacation, so there's no one else inside and the air conditioning isn't running and no lights or appliances are on. So this would actually make it the world's cheapest zero energy ready home, I think, Sam; if you can just get rid of the people from the homes, then it makes it a lot easier to stop using energy. But that's not my point here. So let's say that it's a comfortable 72 degrees inside and a painful 105 degrees outside. And let's say that it stays exactly 105 degrees outside for days on end, not even cooling down at night. So this is sort of like what Washington, D.C. feels like in the summer. And energy will be traveling from the outside of the house to the inside of the house, from more to less. And given enough time this house would eventually heat up to 105 degrees. So if the house is guaranteed to eventually heat up to 105, then what good is a thermal enclosure system, anyway, right? Well, the value is that a complete thermal enclosure system can slow that process down. It can resist the transfer of heat from outside the home to inside the home.
Slide 12: The second thing you need to know is that you can quantify the amount of heat being added to your home using one helpful metric, Btus. So Btus stands for British thermal units and one Btu is pretty small. It's about equal to the amount of energy in a single match. Now, this metric, Btu, is going to come up a lot in the presentation, so it's certainly something that you don't want to forget.
Slide 13: Now there are actually three ways or modes that heat transfer can occur So conduction, convection, and radiation. And I'd like to touch on each of those. So conduction happens when two substances of different temperatures touch each other. So for example if the air outside a home is in contact with the clouding on your exterior wall, then if the air's hotter it will slowly conduct heat to the clouding. Then the clouding will slowly warm up and it will warm up the sheeting that it's touching. And so on and so forth. Eventually the heat will be conducted all the way through the wall into the home. The second form is convection. So convection happens when a fluid like air moves from a hotter location to a cooler location. For example, wind may blow that hot air through the cracks and holes in your thermal enclosures system, moving the heat directly into your home. And the third mode is radiation, which occurs even when an object is hotter than its surroundings. This happens even if the objects aren't touching. And even if there's nothing between the objects. So for example the sun radiates its energy to all the surfaces of your home. And the windows in particular tend to heat up and then re-radiate a lot of this energy to the inside of your home. This is something we've all experienced firsthand. You can feel the heat coming from the sun through a window even on a cold winter day. Now as the heat is transferred into the house, the temperature will start to rise. And if no heat was transferred into your home and no heat was generated in the home, then the temperature would stay exactly the same. This is actually a really important concept. So if you can improve your thermal enclosure system to slow down the rate of heat transfer, then the home will maintain a more constant temperature, stay more comfortable, and require less energy to remove the excess heat.
Slide 14: So with this in mind the thermal enclosure system rater checklist has five sections: High-performance fenestration, quality- installed insulation, fully-aligned air barriers, reduced thermal bridging, and air sealing. Together, they're designed to reduce the heat transfer via conduction convection or radiation. This results in a home that's more comfortable with less energy. This is a good idea for any home, obviously, not just for an Energy Star Certified Home or a Challenge Home. OK, so that's all we're going to say about the thermal enclosure system, because most of our partners have gotten a pretty good hang of this by now. I'll stop there just for a second.
Slide 15: Joe, if any questions have come in that you think we should address on the thermal enclosure system, or if people do have questions about that part, I'd say go ahead and ask it now. Otherwise, I'll move on to number 2. So let me give Joe a second to look through that and see if anything has popped up. Alright, hearing none, I'll go ahead and proceed. So I hope that everyone then is on-board with thermal enclosure system. So moving on to the second system, which is the HVAC system. And this is definitely the big one for our program. Now, a complete HVAC system is really important because heating and cooling equipment that's high- efficiency, properly designed and installed, and combined with a duct system that's insulated, sealed and balanced, maintains comfort with less energy. That sort of sounds familiar, hopefully, because this is analogous to the value proposition for the thermal enclosure system. And the ventilation system, the V in HVAC that's missing from almost every home in the U.S., does three things. It helps remove low-quality indoor air, bring outdoor air into the home automatically, and filter contaminants from the air. So this all results in a home with better indoor air quality. And because this system is so important, we actually have not one but two checklists. The HVAC system QI contractor checklist, and the HVAC system QI rater checklist. Let's get into some of the building science that underlies this system.
Slide 16: Now for the heating and cooling system, the contractor has to get these six major design and commissioning steps right. The three design steps are to calculate the heating and cooling loads, select equipment that meets those loads and design a duct system that gets the air from the heating and cooling equipment to the rooms in the house, and then back to the equipment. And if the commissioning tests are to check the airflow at the air handler, check the refrigerant charge, and measure the airflow at the registers. Now today I'm just going to focus on the first three steps, because if you don't get the design right then the commissioning portion becomes a lot less useful as you can imagine.
Slide 17: Alright, so let's start with the first HVAC design step, calculating heating and cooling loads.
Slide 18: Now you've probably heard one or more of these terms floating around on the screen before. Load counts peak heating load, peak cooling load, manual J, equipment capacity. But unless you're an HVAC designer, you might not really be sure of what they all mean. So let's walk through the basics of load calculations to better understand what's going on.
Slide 19: And before we actually get into the heating or cooling load, actually I want to start with a different type that's easier to visualize. So when you go to design the foundation for a building, you want to make sure it's strong enough to hold up all the weight on top of it, right? That's pretty intuitive concept. So to figure that out, you need to calculate the structural load, which is a technical way of saying that you need to add up all the individual weights on top of it. So you have the weight of the building materials, plus you have the weight of the people inside. Let's say this is a library, so you have all the weight of the books. Plus, it's in a cold climate so you have the weight of the snow on top of the roof. Now, despite the fact that you have these different types of weights, you can add them all up in pounds. If you add up all these weights, you get the total pounds on the foundation. This is called the structural load on the foundation.
Slide 20: Now every hour throughout the year you'll have a different load depending on the number of people in the building, the number of books checked out, and the amount of snow on the roof. So the diagram on the left represents one particular hour with no snow, with some people, and with a few books. And the diagram on the right represents the hour with the most weight. So let's say that Dan Brown is doing a book reading, so there are lots of people inside, and let's say it's January, so there's a ton of snow on the roof. This is called the maximum or peak structural load. So once you know the peak load you can design a foundation that's strong enough to hold up all of this weight. That can handle the load during any hour of the year, all the way up to and including the peak load. Does that make sense, hopefully? Based on that structural concept, now we can talk about cooling and heating loads. Instead of figuring out how strong a foundation needs to be, like on the left, you're figuring out how big the heating and cooling system needs to be, like on the right. So let's start with the cooling portion of the load. Instead of adding up the weight of everything in pounds, you're adding up how much energy is being added to the home from every source of heat and moisure. So things like the sun, the hot outdoor air, and the people, the lighting, and the appliances inside the house. So this should sound a little familiar, based on our discussion about the thermal enclosure system and the transfer of Btus into the home. Now, just like the structural load and the building materials, people, and books can all be summed up in pounds for the structural load, the energy added to the home, from all the sources of heat and moisture can be summed up in a single metric, the Btus. So I told you we were going to mention this a lot, and this is why I said that. The Btus are a critical concept for calculating the heating and cooling loads.
Slide 21: Now just like the structural load, the cooling load will be different for every hour of the year, depending on how sunny it is, the temperature outside the number of occupants inside, etcetera, etcetera. So the diagram on the left represents one particular hour, with a cloudy sky, a few people, and the lights on. And the diagram on the right represents the hour during the year when the most heat is being added to the home. This is called the cooling peak load.
Slide 22: So hopefully you're still following along. There's just one more concept that I'd like to discuss. I said earlier that you're adding up all the sources of energy, both heat and moisture. There are actually two types of Btus being added to the home and they both need to be counted. So the first type is sensible energy. Sensible Btus add heat to the home, increasing the temperature. So I've drawn four red cubes here. Each one represents a thousand Btus of sensible energy being transferred into the home every hour. And this is raising the temperature, from 75 to 76 degrees. The second type is latent energy. So latent Btus add moisture to the home, increasing the relative humidity. So I've drawn three blue cubes, each representing a thousand Btus of latent energy, which is raising the relative humidity from 50 to 51 percent. So altogether, you can see seven cubes or seven thousand Btus per hour, some of which are sensible, and some of which are latent. Now one really helpful concept to understand is that if those Btus were removed from the house, then the home would drop back down to a comfortable 75 degrees and 50 percent humidity. OK, so now let's talk about the heating load.
Slide 23: If you understand the cooling load, the heating load is even easier. That's because the latent portion is usually ignored. Here we see the same house, but in winter it's pretty cold outside at 35 degrees and inside it's pretty warm at 70 degrees. So heat's moving from more to less, from inside the house to the outside. And if we add up all the ways the home is losing heat, through the roof, through the walls, through the floors, and through warm air leaking outside of the home, then we get the heating peak load, also calculated in Btus.
Slide 24: So now you can see why it's really helpful to calculate the cooling and heating load. You can think of your heating and cooling equipment as basically Btu machines. So cooling equipment removes Btus from the house and heating equipment adds Btus to the house. And just like knowing the peak structural load tells you how strong a foundation needs to be, the peak cooling and heating load tells you how many Btus the HVAC equipment needs to be able to remove and add to keep the home comfortable. And notice that we haven't even talked about the type of heating or cooling equipment yet. So let's say the heating load on the home is 60,000 Btus per hour for a furnace. Now how will the load change if a boiler is used instead? Will the heating load decrease to 48,000 Btus? Will it increase to 72,000 Btus? Will it stay exactly the same? Well, the correct answer is that the heating load will stay exactly the same because the load for the home doesn't change based on the equipment that you choose. So whether you choose a furnace, a boiler, or a heat pump, the equipment will still need to add 60,000 Btus per hour to meet the peak heating load.
Slide 25: Now let's revisit that structural load one more time. Thankfully, buildings don't fall down too often in this country. That's partly because structural engineers use a standard process for calculating the peak structural load, usually the international building code. That way, different designers can look at the same building design and come up with basically the same load. Similarly, we have a pretty standard process for calculating the peak cooling and heating load. It's called Manual J. It was developed by the Air Conditioning Contractors of America, or ACCA.
Slide 26: This is kind of like a manual from IKEA that walks you through the steps to assemble a piece of furniture so it always looks the same. In other words, Manual J will walk you through the steps to calculate a peak cooling and heating load so it's always about the same for a given house. Now most of the time Manual J's on the software to help automate that process and ACCA maintains a list of approved Manual J software, which is shown in the link here.
Slide 27: That actually brings me to my second poll question. So which program do you most often use or see HVAC designers use to calculate loads? So you have four options here, Wrightsoft's Right J program, Elite Software's RHVAC program, FSEC's EnergyGuage program, or something else. So I'll have Lindsay go ahead and launch the poll, and report back.
Slide 28: Poll is in progress.
Great, great; thanks, Lindsay. This is where I need like the "Jeopardy" music to be playing along as people buzz in. ... How are people doing on that side?
Think we're just about ready. Alright. I'm sharing the poll results. Dean, can you see that?
Slide 29: I actually am not seeing the results on this end. Can you just read off the results for me?
Sure thing. 49 percent chose Wrightsoft Right J. 13 percent chose Elite Software RHVAC. 2 percent chose the third option, and 36 percent chose other.
36 percent? Wow, that's great. OK. Interesting. So maybe it would be of interest to maybe have some people ... they can type into the question box, actually. I'm sort of curious to know what some of the other options are. We can revisit that toward the end of the presentation. Maybe Joe could take a look at that and as the responses come in. So most of the partners that we've talked with on the Energy Star program I think have focused on Wrightsoft and Elite, but clearly there's some other options out there. Alright.
Slide 30: So let's recap what we've covered so far. Just like a structural load tells us how many pounds a foundation has to hold up, a cooling load tells us how many Btus the cooling equipment needs to remove from the home. And the structural peak load is a maximum weight the foundation will need to hold up, while the cooling peak load is the maximum number of Btus per hour that need to be removed from the home. And finally, ACCA Manual J is the most commonly used standard for calculating cooling and heating peak load. OK.
Slide 31: One HVAC design is down, and now on to step 2, selecting equipment that meets those loads.
Slide 32: So the good news here is that calculating heating and cooling loads is not only the first but probably the most difficult step in the three-step design process. So you survived step 1; congratulations. So step 2 in the process is what we're talking about now, and relative to ACCA Manual J, selecting equipment using ACCA Manual S is a cinch. In fact, the equipment selection process is so simple ...
Slide 33: that I can actually just explain it on this one slide. So let's say that we have a house and we've calculated its cooling load to be 35,000 Btus per hour. So what's our goal for this house? Well, we want to select equipment that can remove 35,000 Btus per hour from this home. Pretty simple. If it can do this, if the equipment can remove every Btu that was added, from the temperature and the humidity it will stay a comfortable 75 degrees and 50 percent humidity. Now if the house was smaller and had a cooling peak load of only 22,100 Btus per hour, then we'd want equipment capable of removing those 22,100 Btus per hour from the house. And if it was a big house in a hot climate and the cooling peak load was 49,400 Btus per hour, then we'd want equipment that could remove exactly that many Btus per hour from the home. So this is called the equipment's capacity, and it's a key term. Every time you hear the phrase "cooling capacity," think the number of Btus that the equipment can remove in a single hour. You can see why this term is a helpful shorthand for saying Btus per hour that the equipment can remove. So every time I say that, cooling capacity, that's what you should be thinking of. OK?
Slide 34: Now the selection process for heating equipment is just as easy. Let's say the home has a calculated peak load of 51,300 Btus per hour. So what's our goal, then? Select heating equipment that can add 51,300 Btus per hour back into the home. And that's the equipment's heating capacity. Every time you hear me say the phrase "heating capacity," think, the number of Btus per hour that the equipment can add to the home. So let's give this a try. Heating capacity, cooling capacity, heating capacity. Is it triggering the right messages in your head? OK. Hopefully it is.
Slide 35: I'll have to take your word for it, because I can't hear you on this end. So if you take nothing else away from this stuff, it should be that in concept, equipment selection is super-simple. The goal of the second step in the design process is to pick equipment with a capacity that equals the load. And you might be thinking, if equipment selection is so easy, then why do we even need a standard for it? And that would be a really good question to ask. So let's think back to our example for the answer. There's a finite number of equipment models out there to select from in this world, and you might not be able to find equipment with a cooling capacity that's exactly 35,000 Btus per hour. So if you can't find an exact match, then what's considered close enough? And the answer to that question is where ACCA Manual S comes in. It defines the range of acceptable sizes for the designer to use. So for example, the current Manual S says that the total cooling capacity of the selected equipment should fall between 95 and 115 percent of the cooling peak load. And it says the heating capacity of a forced-air furnace should be between 100 and 140 percent of the heating peak load. So just like ACCA Manual J helps standardize the calculation of loads, so different designers will get similar results, ACCA Manual S helps standardize the selection of equipment using those loads. It's just a lot simpler than the complexity of Manual J.
Slide 36: Now hopefully you can see that these first two steps in the design process go hand in hand. So to illustrate this, let's consider a parachuting elephant. I'm sure you've all seen this analogy before. This poor elephant here is terrified because he's just figured out that he weighs 8,000 pounds and whoever picked out his parachute picked one that's only rated for a 1,000-pound elephant. Now this could have happened a few ways. Suppose the scale he was weighed on was broken, and it said he only weighed 1,000 pounds. And so he got a parachute rated for that. That scenario won't end well. Now let's also suppose the scale was right and said that he weighed 8,000 pounds but the skydriving instructor didn't believe it, and so he gave our elephant a 1,000-pound parachute. That won't end well, either. So the only way that this is going to work is if the scale says the elephant's 8,000 pounds and you get the parachute rated for 8,000 pounds. It's just like for piece of HVAC equipment. If you calculate the wrong load, but pick the right equipment using that load, you'll fail. And if you calculate the right load but then you pick the wrong equipment using that load, you'll also fail. So each step alone is meaningless. It's only when you calculate the right load and select the right equipment, that these two steps become very valuable.
Slide 37: So let's recap what we learned in this seciton. Step 2 of the design process is to select equipment with the capacity that offsets the peak load, particularly using ACCA Manual S. The cooling capacity is the number of Btus the equipment can remove from the house in a single hour and the heating capacity is the number of Btus the equipment can add to the house in a single hour. ACCA Manual S helps standardize this process by defining tolerances. How much bigger or smaller the equipment capacity can be relative to the peak load. And selecting the right equipment, that's not too big and not too small, is really important. Equipment that's too small can't keep up, even when it's on all the time. Equipment that's too big turns on and off too often, resulting in worse comfort, efficiency, and durability. So properly scienced equipment can best keep the home comfortable while maintaining efficiency and minimizing wear and tear.
Slide 38: OK, so two HVAC steps down, now on to the third and final HVAC design step: Designing the duct system.
Slide 39: After calculating load and selecting the equipment, the third design step in most homes is actually designing the duct system.
Slide 40: The building science behind all that starts with the HVAC fan. So a fan is pretty simple. It uses energy to push air in one direction. Now think about a balloon that's being blown up. Like a fan, you're using energy to push air in one direction. As you blow air into the balloon the pressure inside the balloon increases. In fact, that's why the balloon is inflating. Because the pressure inside the balloon is now greater than the pressure outside the balloon. Now once a balloon is inflated and tied off, you're not blowing any more air into the balloon and you're keeping the air from escaping. So the balloon stays inflated.
Slide 41: The pressure is still higher inside the balloon even though no air is moving at all. Now the amount of pressure inside the balloon is called the static pressure. This is another really important term. Now let's say you poke a really small hole in the balloon that just lets out a small stream of air. If the air is forced out of the hole and starts to move, and if you held your finger in that airstream, you'd feel the pressure of the moving air pushing against it. So just like a windy day, when you feel the pressure of the wind pushing against you, this pressure, which is caused by the moving air pushing against you, is called the velocity pressure. In fact, for the second balloon, the leak, the static pressure has decreased and the velocity pressure has increased. So in you're heating and cooling systems, the static pressure and the velocity pressure are commonly measured in units of inches water column. That's another really important metric.
Slide 42: So let's think about the fan in the duct system again. The fan is using power to push air into the ducts. Now let's consider a hypothetical duct system that's built without any registers and it seals up really tight. When the fan turns on and blows air into the ducts, maybe a little air leaks out through the cracks like a small hole in the balloon. Where you have in a system with a very high static pressure and a very lot velocity pressure. There's not much air coming out of the ducts at all. OK.
Slide 43: So now let's assume something that's a little more realistic. A number of registers are added to the duct system and assuming that fan is using the same amount of energy, the static pressure drops much lower and the velocity pressure is much higher. This is like a balloon with a big hole. So you can see that the static pressure and the velocity pressure are related, giving constant power into the fan, as the velocity pressure goes up, the static pressure goes down, and vice versa.
Slide 44: Alright. I bet you weren't expecting this image next. So the idea of static pressure may sound super-theoretical, like you learn about it during this webinar and never hear about it again. But in reality, HVAC designers apply this concept every day to stub design. In fact, one of the designer's primary tasks is to calculate how much static pressure the duct system is designed to have. In concept, the designer has a static pressure budget to spend. So let's talk about this in more detail. To help illustrate this, I'm going to throw out another analogy. So let's say you're going to take a trip in your car. And your starting point is your house and your ending point is back at your house. And let's say you live in New Jersey, so you're going to have to pay a bunch of tolls during this trip. You want to make sure that you've budgeted enough money so you can pay for all of the expected tolls, right? So a hundred bucks, in this case.
Slide 45: So how does this relate to duct design, possibly? Well, the designer basically has the same task. The air is your vehicle, and it's going to go on a trip to drop off Btus to a room or to pick up Btus from a room, and then bring them back to the equipment. The starting point is the heating and cooling equipment and from there it's going to go to the supply ducts, into the room, and then from the room back into the return duct, and end up back at the cooling equipment or heating equipment where it began. And every step along this trip the air is going to encounter tolls. Instead of paying these tolls with money, though, the toll is paid in, as you might expect, static pressure. So with that in mind, let's revisit the duct scenario.
Slide 46: So here we see the fan and duct system again, but this time in a whole new light. So the air leaves the fan and then what happens? First it has to get out of the box. The fan is inside. So let's say that a static pressure toll of point 1. And next it travels along a certain length of duct, so another point 1 toll, then the air hits a bump in the road a crushed duct, so it imposes another toll of point 1. Then it's a 90-degree turn, another toll, and finally it goes to the supply register. So the air has finally made it to its destination, the room. But now it has to get back home. So it travels into the hallway and goes to the return grill. This imposes another toll. Now unfortunately, the filter is way too small for the amount of air going through it. This is like a bridge during a traffic study. Nothing but trouble. So you have a big toll here of point 3 inches water column. And it finally hits a 90-degree bend in the turn, another toll at point 1, then finally makes it back home. Now it turns out that the static pressure toll on the return side of the system is negative, because the air is being pulled to the fan through the return ducts rather than being pushed by the fan through the supply ducts. But that doesn't matter.
Slide 47: To figure out how hard the fan has to work, you just need to add up the magnitude of the static pressure on the supply side and the static pressure on the return side. And if we sum up all the total static pressure of the tolls, in this case we get 0.95. Now if I sum up all the tolls except for the one for the box that the fan chips in, if I just cross off that first one then I get 0.85 inches water column. This number, the sum of the static pressure excluding the equipment that the fan ships in is a really key term. It's called the total external static pressure. Now why is this so important? It's because for any given fan, the manufacturer publishes the total external static pressure that it can overcome. In other words, the budget the designer has to work with. Right? So this takes that toll procedure analogy all the way to the HVAC design process with the ducts. Here's the budget that you have to design your duct system.
Slide 48: So let's recap all the major concepts we learned in this section. One, a fan uses power to move air. Two, the fan creates two kinds of pressure in the duct system, static pressure and velocity pressure. Both of these can be measured in inches water column. Three, I refer to the duct system, the straight duct run, the turns, the registers, the grills. They all impose a static pressure toll. And the sum of all these tolls excluding the static pressure of the equipment that the fan chips in is the total external static pressure. The manufacturer of the fan tells the designer how much total external static pressure the fan can overcome. Basically, the budget the designer has to work with.
Slide 49: Alright. You made it through the three-step process. So finally, let's touch upon the other part of HVAC, the ventilation system. While I've left it to the end of the HVAC section, at least I haven't left it out altogether like most homes in the United States. A little dig there.
Slide 50: So I'd like to start with the concept that consumers value indoor air quality. Now why do I say that? Because we don't typically have consumers asking for it explicitly, or demanding it in their homes in the home-buying process. So why would they value it? Well, let's pose the question a different way. If you offer a consumer the choice between two homes that are identical in size, finishes, locations, and other amenities, with the only difference being that one of the homes has better indoor air quality, they'll probably choose that home, right? You would probably do that, as well. So it sounds good, but what does indoor air quality actually mean?
Slide 51: How do consumers know what they're getting in their home? Well, to our program, and to Challenge Home, it means the air quality that homeowners are satisfied with, and that doesn't contain contaminants at levels known to harm them. And that definition is kind of interesting, because part of it links the indoor air quality explicitly to the homeowner's level of satisfaction. However, some of the contaminants in the home may not be perceptible to the homeowner. So the other part of the definition is to have systems in place that help lower these contaminants. And actually this is not just our definition.
Slide 52: It's the definition of the industry standard for indoor air quality of homes. That standard is called ASHRAE 62.2. And in this presentation, almost every thing we talk about comes directly from the ASHRAE standard. Now the primary goal for the Energy Star program is to meet this standard so that we don't sacrifice indoor air quality in exchange for a more efficient home. You shouldn't have to sacrifice one to get the other.
Slide 53: So what sort of measures will the homeowner notice? How is the building science playing into these ventilation systems? Well, in the kitchen, an exhaust fan provides the homeowner with the option of expelling odors, moisture and cooking particles while they're cooking. So my old apartment, all I had was a recirculating fan. It was really noisy and just blew the odors and whatever I was cooking right back into my face. So having a fan that ventilates to the outdoors is a big improvement for a lot of homeowners. It actually empowers them to control their air quality in the kitchen, an area that's known to produce contaminants.
Slide 54: nd bathrooms, just like the kitchen, we're giving the homeowner the ability to control their air quality in another area with known contamination sources. Now most bathrooms in your home already have bath fans included, which is great. But we're sort of kicking it up a level by having a limit on the sound rating and having verified airflows. We're not looking for a silent fan with these requirements, just one that isn't so annoying that no one will use it. This is one of those features that a homeowner would come to expect in a quality new home.
Slide 55: Third, in an Energy Star certified home, you have a whole house mechanical ventilation system that brings in outdoor air automatically. So you won't have to take the time each day to open your windows and close them. The system sort of takes care of that for you. So just like a DVR is set to record your favorite shows without you having to remember when they're on, a whole house ventilation system provides you with outdoor air without you having to remember to open and close the windows each day.
Slide 56: So those are some of the basic features the consumer's going to notice. We'll talk more about later, about why these are really important. So if you want to go further and earn the gold standard in indoor air quality, then you should learn more about the Indoor AirPlus program. Now for us, this is a complementary label for Energy Star Certified Homes, but those that have participated in the Challenge Home program this is another key mandatory prerequisite for the program. In fact, Energy Star certification plus Indoor AirPlus, together, combined, represent a lot of the requirements you have to do to get to Challenge Home. So the Indoor AirPlus program builds upon Energy Star by adding important protections like radon control, reduction of all the organic compounds and VOCs, and pest management. Indoor AirPlus offers a complete indoor air quality package with only a little bit more effort. And Indoor AirPlus has actually just come out with revision 2 of their guidelines, which include alternatives and some exemptions to some common hurdles that were preventing raters and builders from participating in the program. So it's really important, especially for those that are participating or thinking about Challenge Home. It's easier than it was before to meet this prerequisite. So we encourage you to learn more about the Indoor AirPlus label and I've included the link here. Now let's go for the gold standard for air quality back to the other end of the standard which is standard practice. So many new homes are built in almost all existing homes were built, without being tight. Now why did that happen?
Slide 57: Because it's cheaper that way, and consumers traditionally have low expectations for comfort. Many have never lived in a comfortable home before. They don't even know it's possible. So most homes are really leaky. And this actually has some advantages, but also a lot of disadvantages. One of the few advantages it has is that when outdoor air leaks in, it helps dilute any contaminants in the house. And the second advantage is that if the ceiling, the walls, or the floors get wet, the outdoor air leaking through them helps dry them out.
Slide 58: On the other hand, there are a lot of disadvantages. So the first is that you only get outdoor air when the wind blows, or when the occupants open the windows, or when there are extreme temperature differences between the inside and the outside. The second is that the outdoor air can leak through a bunch of pathways that lower the air quality before it even gets into your house, like through an attic or through a garage with a bunch of chemicals in it. The third is that the air can be really uncomfortable. And the fourth is that it takes a lot of energy to condition all the extra air that leaks in and leaks out.
Slide 59: So to both address these disadvantages and maintain the advantages, the Energy Star program has a few requirements which we think add value to a home. So the first, which you should all be familiar with, is to build the home tight. This reduces the cost of conditioning the air, and it improves the comfort by reducing drafts. The second is to have an exhaust fan in the bathroom and the kitchen and a filter in the HVAC system to help remove contaminants from the house. Of course, many homes already have these today, but not all of them work properly as designed. The third is to bring outdoor air into the home in a controlled way, to dilute the remaining contaminants. Almost all homes are missing this today. And the fourth is to pay extra attention to the details that keep water out of the ceiling, the walls, and the floor. Given that you don't have a lot of outdoor air moving through these assemblies to dry them out. Now many homes pursuing energy efficiency, like a HERS-rated home, also pursue a tight house as a key strategy. However, a HERS rating doesn't include verification of the exhaust fans and the filters, or require a mechanical ventilation system to bring outdoor air into the home, unless the rating is going to take full credit for reduced infiltration. And finally, it doesn't include any key durability details relating to water management. So in summary, we think that indoor air quality is something that's valued by consumers, and directly related (audio lost) ...
Slide 60: ... efficiency may come at a cost of reducing indoor air quality. So while the requirements for our program require a bit more work we think it's well-worth the added value that you get.
Slide 61: And that brings me to my third poll question. I'm kinda curious, especially among this crowd, what mechanical ventilation system do you most often see in certified homes, whether they be Energy Star or Challenge Home?
Slide 62: So a few common systems are listed here. Exhaust fan is the first. A ventilation inlet on the return side of the HVAC system is the second option. A ERV or HRV is the third option. If none of those apply, then pick D, other.
Poll is in progress.
Alright. I'm gonna go ahead and close the poll.
You'll probably have to read off the answers to me one more time.
Slide 63: For results, though, we had 61 percent chose exhaust fan. (audio lost) chose ventilation inlets. 18 percent chose ERV HRV, and 4 percent chose other.
Interesting. So exhaust fans all made it, which I'd sort of expect. That's sort of the cheapest compliance option for 62.2. And depending on who you talk to, some people say that works just fine. It's interesting to hear that actually so many people are stepping up to ERVs and HRVs already. I think what we're seeing already is sort of product manufacturers starting to respond to the fact that for the first time a lot of new homes actually need ventilation systems. So you're seeing a lot of new products that are in development or now available in the marketplace that weren't available just a few years ago. So I'm really interested in seeing how this trend continues to change moving forward. I would expect more and more sort of balanced energy-efficient ventilation systems. So great to hear a little bit of insight from the audience today on that. Alright, so that wraps up the HVAC system.
Slide 64: I told you that would be the big big lift for this presentation. So much of what we're focused on right now in the Energy Star Certified Homes program is getting the ventilation system, the heating system, and the cooling to work like they're supposed to work. So the thermal enclosure system, which we already talked about, is something that more people are familiar with. I'm going to end with the third system, the water management system, with just a few slides. Because it's also something that people are generally more familiar with already. OK, so why is a water management system even important in the first place? Well, one that directs water off of the roof down the walls, and away from the foundation and site, as well as keeps the building materials from getting wet, improves the durability and the indoor air quality of the home. Now this is a pretty intuitive concept. It's not just a theoretical concern for Energy Star builders. Any builder that's gone through, say, a class action lawsuit over water management defects knows how painfully important these details are.
Slide 65: And it's really just one building science concept to keep in mind. Many materials used in building homes are not durable when they get wet. So think of gym clothes. If you hang them out to dry after a workout, they can probably be used the next day. But if you were to tie them up in a garbage bag overnight instead, where the moisture is trapped inside, you're probably not going to be using those clothes again, unless you want the gym all to yourself. So the same concept applies to most building materials that get wet and stay wet. So it's important for every home but especially high-performance homes, to allow these systems to dry out, if they do get wet, to try to prevent them from getting wet in the first place. Now why is that? Remember that the complete thermal enclosure system is a key part of our homes. And that improves comfort and efficiency by reducing heat transfer. Reduced heat transfer means it will take longer for wet materials to dry out. So it's extra important to keep them from getting wet in the first place.
Slide 66: So let's look at how this translates into actual measures in the home starting with the foundation. There are basically three major features to control moisture down there. The first is to provide a continuous layer of moisture protection that prevents water from moving from the ground into the foundation. Second, you want moisture to move away from the house. That means sloping surfaces so surface water moves away from the foundation instead of toward it. And third, you need to include a perimeter drain at the base of your foundation walls to drain away moisture that's in the ground. So those are the basic features we focused on for foundation. And walls, we're focused on one basic feature, a continuous layer of moisture protection from the top to the bottom of the walls. By continuous we mean that if you take your finger and trace your wall from the top to the bottom like a raindrop, it will never find a spot that can go into your wall. What happens to all that water when it gets to the bottom? There you need flashing, a material that will provide a continuous barrier as a transition between the wall and the foundation. That way, when the water rolls away from the transition you want it to run away from the transition, instead of into that transition. The other most common place where the wall is not continuous is at windows and doors. So at those locations, you also need flashing to redirect the water. And on roofs, we're focused on three major features. First, you want a continuous layer of moisture protection on your roof that moves water from the top to the bottom. And just like flashing in the bottom of the walls, it's also important to have flashing to protect that transition between the roof and walls. Second, for many homes you want to collect that water at the edge of the roof and carry it away from the house with gutters and downspouts, rather than letting it fall to the foundation. And third, you want to add an extra layer of protection where the roof is most susceptible, in valleys and penetrations in the roof and in cold climates at the eaves.
Slide 67: So in summary, in less than five minutes I've given you a basic overview of the major features we're looking for with the water management system. Think of how important each of these are to the house and how expensive they would be to correct after the fact. If there's a problem with the foundation, it might mean excavating, or problem with the wall, it might mean removing the siding or replacing the windows and doors. And if there is a problem with the roof, it might mean removing the shingles or even the roof itself. These materials are really important, or these features are really important to get right in every home but especially important in an energy-efficient home. Now the main building science concept we discussed is that most building materials don't like to stay wet, and including these details helps them be more durable by staying dry. Now nearly every requirement in our checklist is actually required by code. That means that most builders should already be doing this checklist. But it's especially important that they confirm this in homes that are certified under Energy Star or Challenge Home.
Slide 68: Alright, let's wrap it up. So I've spent just about an hour talking about all the building science concepts that underlie Energy Star. But who cares about building science, anyway? It's not something that consumers walk into a new house and say, I want this home with building science! It doesn't sell itself. It's not particularly sexy. So the things that the building science foundation provides, in terms of value, are the really key points. So for builders, it means greater quality and process control. Reduced costs from warranty issues and customer complaints and maximum value for the money invested. For HVAC contractors, it means reduced callbacks for comfort issues. And the justification to invest in higher-value products and services. And for homeowners, our ultimate audience, it means lower utility bills, better comfort, durability and quality, and a more livable home.
Slide 69: Alright. So, if you thought that this webinar was at all valuable, then hopefully you'll consider joining us for some of the other webinars that we offer. These are some of the ones that are coming up, which go into greater detail about the design process working with Energy Star and Habitat, cost-effective strategies and air sealing done right. You can visit our website to learn about those webinars for both Energy Star and now we've also listed the Challenge Home webinars on the same site. So you can really easily see what's addressing Energy Star and how does Challenge Home build upon that with their requirements and their webinars. So I really encourage you to go there and check it out and attend some of the great webinars that they put on.
Slide 70: And last but not least, I've included my contact information here, some of the key sites for Energy Star Certified Homes. And if you have any questions that we don't address today, feel free to email our team at EnergyStarHomes@EnergyStar.gov. And with that, I'll turn it back to Lindsay and Sam and Joe, and we can walk through any questions that came in.
Thanks, Dean. Can you hear me?
Alright, great. We did get a number of good questions so I'll go through them, and answer them as you can. The first question we got is on the difference between an air barrier and air ceiling, and how those things are different and how they work together. Can you talk a little bit to that?
Sure. We actually provide a definition of air barrier on our checklist, which is basically a durable material that resists the flow of air, with sealing to help ensure that the seams and edges don't allow excess airflow through them. So I'm not getting into a real technical definition of air barrier in this instance. I'm talking about the concept that we're trying to go after. So with OSB, that can sometimes be the primary air barrier for the exterior of the home, and then you'd be using sealing in certain locations where you'd have excess airflow. So in terms of how this plays into the Energy Star program, we talk about essentially the locations where you need to have these air barriers in place. Key areas like behind tubs, behind stairways, where porches intersect with the roof of the house or the wall of the house. Those are common areas where no air barrier is included, and that's where we focus the attention of our partners.
Great; thanks, Dean. We did get a couple of questions as you were going through the section on ACCA Manual J. On sort of looking for advice on whether that manual is effective on something like a low-load HVAC system, or perhaps a ventilation-only system, where maybe your HVAC isn't ducted but your ventilation system is. So can you talk to that, whether Manual J is still applicable, or whether there's any other advice out there?
You know, to be honest, this is a situation we haven't run into too much within the Energy Star program. We definitely deal with low-load homes in the sense of multifamily units where you're talking about relatively low loads but not sort of ultra-low loads. In concept, Manual J should work for any house because it's sort of a physics-based approach to calculating the heating loads. But there may be some cases at the very far end of the spectrum where some of these homes (inaudible) they have a Manual J don't apply as well to homes. I'm not aware of that being the case at all. It's just that I haven't heard as much from our partners having experience in that area. So I think I would defer judgment for the moment on that.
OK. This next question may be something you don't want to wade too far in, as it's ASHRAE 62.2, but I thought maybe you could comment a little bit on it. The question there is, how do you deal with the issue of people being concerned bringing in contaminants from the outdoors whether it's a supply approach in a hot humid climate, or whether it's someone who's concerned about bringing in allergens or something like that? Is there any ventilation advice you can offer there?
Sure, well, first keep in mind what we're trying to do with the ventilation system. Every home is having outdoor air coming into the house, but for most homes it's only coming in through leaks and cracks in the house. There's no way to control that process, and there's no way to sort of improve the air quality before it comes into the home. So in a hot, humid climate, most homes have humidity issues regardless because they have hot, humid air leaking into the house. With our approach we're first of all sealing up the enclosure so we're not having as much of that sort of errant airflow into the home. We're trying to control the amount that's coming in. So when it comes to allergens, you know, one key advantage of a ventilation system is that you can pass that air through a filter before it actually gets into the house. If you're really sensitive to certain allergies, then that would be a key reason to have a ventilation system so you can control the flow of air and filter those allergens out. When it comes to humidity issues, I think the key point is that hot humid climates probably in the long run you'll see more and more homes working with dehumidification. Ultimately, and this is true for any home whether it's Energy Star or not Energy Star, if you want to keep the moisture out of the house, you need to have some means to remove the moisture. And so it's not a mandatory requirement in Energy Star right now to have dehumidification in every Energy Star Certified Home in a humid climate, but I think you're starting to see more partners explore that as a way to deliver ventilation more effectively. Is that as high level thought on that? And I'm sure we can have a much longer conversation offline if we need to.
Hey, I just want to echo what Dean's saying because particularly as you move to Challenge Home, you're getting into homes that are even more robust in terms of the thermal enclosure. Which means the swing seasons are going to get longer on the front and the back end of the summer. Which means also you have longer time periods with no space conditioning and more time when you have some latent load, which further emphasizes the importance of having a central dehumidification strategy or HVAC equipment that's designed to provide dehumidification independent of the cooling and heating. So this gets really important in low-load homes.
And I guess just since you're echoing some of the things I'm saying, Sam, I'll go into a little more detail. So we have some partners who are definitely looking at, well, let me say that, when people think of dehumidification, I think the first thing that comes to mind is a very expensive whole house dehumidifier that is built into the HVAC system. And that's sort of out of reach for a lot of our partners right now. So we have a number of partners exploring alternatives. One is a plug-in dehumidifier. Something that you'd see at Home Depot. It's not fancy. But what they tend to do is put it, conceal it behind a grill, or something else, and they'll drain the condensate directly into the condensate line with the HVAC drain, and that way there's less maintenance for the homeowner and it looks a little bit more professional, and it actually sort of gets the job done in terms of removing moisture on a regular basis from the house. Some people have had really good luck with that. The other thing we're starting to see partners explore is, I don't need to remove all of the moisture from the home; I just need to focus on removing the moisture from the ventilation air that's coming into the home. So they're looking at smaller systems that are just designed to handle the capacity of the ventilation air, and in that way they'll be bringing in dry air, pressurizing the house with dry air. It will also help prevent moisture from migrating in from leaks and holes in the house. Those are a few sort of more detailed approaches that people are exploring on dehumidification, and I think again you'll see more and more products coming out to help facilitate that.
OK. We had one more question I wanted to get to here, and that was what advice can you offer to people who are having trouble locating an HVAC installer who is certified?
You know, so far what we've seen ... So for a little bit of context, the Energy Star Certified Homes program has been around now for close to 20 years, and yet with version 3 we're essentially in year 1 of a new market transformation effort to get the HVAC industry up to speed, delivering these complete HVAC systems in our home. So I definitely understand the frustration of some partner that can't find a certified contractor yet. So far what we've seen in the marketplace is that the key sort of mover and shakers in getting these contractors credentialed is the builders themselves. When they need these services to be done to certify the home, that tends to help bring the contractors on board. And so I think that's part of it, is finding the builders that are willing to make that happen. The other part is explaining to the contractor the value that they're getting out of this. This is sort of an amazing concept that we didn't discuss today, but if we think about what a rater is doing and what a designer is doing, an HVAC designer, it's almost 100 percent analogous. Both of them are basically doing load calculations on the home. They almost need the identical inputs to do their job. And you have a rater going out into the field every time with a certified home, making sure those inputs are actually correct in the field. And so how many times does the designer get sort of screwed because they design a system assuming that certain things are going to be done in the home and that never gets verified in the field, because they're never paid to go out in the field and verify it. So I think there's actually a really strong value message that a home energy rater should be an HVAC contractor's best friend helping making sure that the design is actually installed the way they designed it I think if you can message the value of participating in the process, that Energy Star and Challenge Homes are the easiest homes to design HVAC systems for, that might help bring some of them along, as well. I know it's a bit of a painful process. We have a lot of people working really hard in the field to make this happen. And it's improving each day. But it's going to take some time still before it really becomes standard practice.
OK. Well, those are the main questions, and I tried to combine a few that were very similar, but the only other thing that I was going touch was the list of softwares that you ask people to enter. Some of the things were things like SteckPro in the Northwest, something people use for HVAC design. Some people use just the ACCA Manual J worksheet, as opposed to a software PHPP was mentioned, which I unless I'm mistaken is a passive- house-connected thing.
That's my understanding as well. OK.
One person wrote in "rule of thumb," so I'm not sure if that counts as a software or not.
Gotcha. I think you'll see more and more of the industry moving toward software, even though it's not a mandatory requirement in our program yet. Just because of the complexity of these calculations almost make it a prerequisite for achieving accurate loads, and I think you see a lot of people standardizing around some of the solutions that are out there. Pactific Northwest does in fact have a sort of custom solution for that region right now. And we should add that probably in the future for that audience, as well. But that's great to hear so many people using software for the most part. And I'll throw out one question, actually. This is something that Sam brought up. If you guys, if the audience has other topics they would like to hear about, in terms of the overlap between Energy Star and Challenge Home either you want Sam to be presenting, and his team, or me and our team presenting, feel free to write in to EnergyStarHomes@EnergyStar.gov, or to his team, with suggestions and we can definitely try to develop some new webinars for you guys that meet your needs.
Slide 71: OK, great. Well, I have a few wrap-up things to talk about here. We really appreciate Dean spending time with us today. This is a list of resources that the DOE Challenge Home program or soon to be the DOE Zero Energy Ready Home program, that we've compiled. Here's our website where you can find partner agreements and you can find other people who are doing Challenge Homes, and raters, and if you're a rater you can find builder partners here. We'll also list the webinars that are upcoming and then we hope to have links to these recorded webinars up soon, as well. And then finally, there's a link to the Building America Solution Center, which is a place to go if you want to look through a really great resource on decades of Building America research that has been compiled and put into one place along with Energy Star resources and other building science guides.
Slide 72: And there is our website again, and if you have additional questions, feel free to email Dean, but also you can email us OEChallengeHome@NewportPartnersLLC.com. And with that I'll turn it back over to Lindsay.
Alright, thank-you. Folks, we're recording online, and thank-you everyone for joining us today, and we look forward to seeing you at our next Challenge Home technical webinar.