You are here

DOE Zero Energy Ready Home Efficient Hot Water Distribution II -- How to Get it Right Webinar (Text Version)

Below is the text version of the webinar, Efficient Hot Water Distribution II -- How to Get it Right, presented in January2014.

Lindsay Parker:
... Tech Training webinar series. My name is Lindsay Parker. I'm working with the Challenge Home program and here to set this up for you. Today's session on hot water distribution is one of a continuing series of tech training webinars to support our partners in designing and building DOE Challenge Homes. We'll have all attendees in listen-only mode, but feel free to ask any questions using the question section in the webinar. We'll cover as many questions as possible near the end of the webinar. So we appreciate your patience. Also, a recording of this webinar will be posted to the Department of Energy Challenge Home website later on. More information will be sent around on that, after the webinar, including a PDF of the presentation. So now I'm happy to hand the reins over to Jamie Lyons with Newport Partners. Jamie is the technical expert on the Challenge Home program and he's going to explain more about the program and what to expect from today's webinar.

Jamie Lyons:
Slide 1:

Great. Thanks, Lindsay. Thanks, everybody, for joining us. I'm just going to queue up the presentation quickly and sort of orient the group before we hand it over to our main speaker / expert, who's Gary Klein. So thanks for joining us today. This is the second in a series of two webinars we're holding on efficient hot water distribution. And a little bit of background, really quickly about the Challenge Home. It's DOE's leading voluntary energy efficiency label for high-performance homes. In the spirit of trying to work and train with our partners, builders, raters, utilities, manufacturers, energy organizations, we've been running a number of four-hour training sessions all throughout the country. Probably some of you have had the chance to take part in one. So in those sessions we go through a lot of good content about how and why builders want to be in this space in the industry, and a lot of that business case and consumer messaging, some coverage of the specs, but we really don't have a lot of time or opportunity in this session to get into some of the finer technical points. How do we do some of the building systems which really make these homes perform so highly efficiently? So in that spirit, DOE in 2014 is running a series of tech training webinars. So that's what we're part of here today. This is the second on efficient hot water distribution. So we'll be running the webinars through the year. There's a whole series of topics upcoming. We'll list our website in a few minutes here, where you can access that upcoming list. And then if you don't have the opportunity to participate live, they'll also be posted on the website in an online recording library, so you or colleagues can access them later on. That's a little bit about the context for today's talk.

Next slide:
And just real quickly, to sort of set the stage, this might look familiar to most of the group, but DOE Challenge Home has very high performance targets all throughout the building: the envelope, mechanicals. And as we look at that, we have to have efficient hot water distribution. So the actual spec, which is built into the program, is brought over from EPA's WaterSense program. This slide lists sort of the basics, so there's a minimum amount of hot water that can be stored between the source of hot water and any fixture. And there are certain criteria that if a recirc system is being used, that recirc system has to meet basic minimum criteria. In essence, we don't want a recirc system which is running extensively and wasting energy in the process when we actually don't need hot water. Also as part of the Challenge Home specs, there is a metric for water heater efficiency, which is part of the target home. And then there's also some requirements for the distribution system as we see here. If you really look at the home and the system, which we try to do, the efficiency of the hot water distribution isn't really just a function of any one part of these but really the collection of the sum of all these parts together. So we need to look at it from that basis, and to help us understand hot water systems from that perspective is Gary Klein, who will be our presenter today. Just a few words about Gary. He's been intimately involved in energy efficiency and renewable energy since the '70s and is an internationally recognized speaker as well as a trainer and educator. Over the past 15 years, he's participated throughout the U.S. conferences, speaking on this topic of efficient hot water, including ATEEE, API, Ashrae, ASPE, CEE, as well as some international venues. Gary also teaches classes around the U.S. for utilities and Green Plumbers USA. And he also consults with builders and plumbers around the country on energy-efficient hot water distribution systems. Lastly, Gary's also been involved in developing hot water distribution specs for a number of leading residential programs in the U.S. such as LEEDS, NHB, Building Green and Spec Image; a couple minutes ago, the U.S. EPA WaterSense program. Gary also has a long history with the California Energy Commission before starting his new firm, Affiliated International Management. Gary, I'm going to turn it over to you here and make you the presenter. So then you can get it started. Just a sec here, I'm looking for the button here ...

Lindsay Parker:
I got it, Jamie. Gary, you should be presenter.

Jamie Lyons:
Is Gary unmuted? We see you, Gary. We don't hear you yet. ... Stand by, folks, while we get Gary's audio set up, please.

Gary Klein:
Can you guys hear me now?

Jamie Lyons:
Yes.

Gary Klein:
Sorry. For whatever reason, everything died on the telephone. What can I tell you. So I do have a question for you, Jamie, before we get started today. Which is, in the Challenge Home specification, what does it say about the fixture flow rates, and what does it say about the dishwashers and washing machines?

Jamie Lyons:
If it's for ENERGY STAR appliances, Gary, as far as the fixture flow rates, Challenge Home in the initial spec had looked at a more rigorous fixture flow rate requirement coming out of the WaterSense program. At this point, the one and only water distribution spec is the hot water system itself. So we're silent on end-use flow rates.

Gary Klein:
Thank-you. That will help as we go forward. Alright, everyone, let's get started. So this is the second part of a seminar. Some of you have been to my in-person seminars, and we could spend days on this stuff, but we're going to spend an hour on the next piece, which is the gist of how to get it right. We have some learning objectives today.

Next slide:
Learn how to deliver hot water to every fixture wasting less than one cup of water while waiting for the hot water to arrive, and wasting less energy than would have been wasted running water down the drain. Evaluate how the DOE Challenge Home / EPA WaterSense hot water distribution system requirements perform, in terms of water, energy, and time. Learn how to integrate the components of a hot water system and the cost-effective -- into a cost-effective, high-performance system that is water-, energy-, and time-efficient. And develop a list of best practices that you can implement tomorrow morning.

Next slide:
Alright. So before going forward, Lindsay, we have a couple of questions for our audience, right?

Lindsay Parker:
Sure thing. I'll launch the first one right now. This is a poll. So we'll spend about a minute for everyone to take the poll and respond, and then we'll show everyone's responses, and Gary, you can take it from there.

Gary Klein:
So Lindsay, when we get the responses on the first one, we'll look at it for a few -- for about 30 seconds or so, maybe a minute. Then we'll go on to the second and the third. OK? Let's get the questions out quickly.

Lindsay Parker:
Sure thing. And now we're collecting votes from the first poll. 65 percent of people have voted.

Gary Klein:
Is my screen being shown at the moment?

Lindsay Parker:
Actually, right now the poll is being shown. Alright. So thank- you, everyone. I'm closing the poll now. And here's the ... I'm going to be sharing ... Here are the answers.

Gary Klein:
So the big bulk somewhere in the ... the big bulk is in the less than a minute category, between 30 seconds and a minute. Interesting. Cool. Very good. Alright, time for the second question.

Lindsay Parker:
Alright. Now I'm launching the second poll. How frequently do you run out of hot water? Please select one. ... Alright, thank-you, everyone. I'll be closing the poll. And now we'll get to see the results.

Gary Klein:
Very interesting. I'm sorry for those of you who run out daily. Maybe you have teenagers.

Lindsay Parker:
Alright, now on to the third poll. How many people live in your household? ... Alright, thank-you, everyone. I'm closing the poll and sharing the results.

Gary Klein:
So ... let's go over the answers to the poll and how they relate to all of this. The question about how long do you wait tells me an enormous amount about the volume of water between your water heater or your recirc loop if you live in a house -- apartment that has one, and the fixture that you're thinking about. And most often for reasons that currently escape me, the master bathroom and/or the kitchen tend to be furthest from the water heater in most houses. Seems a little silly; I think I understand why that happens. But that's the way we design and build buildings. So people wait a long time and develop behaviors to accommodate that. The next one has to do about running out, and it turns out that it's a fear that people have that it's going to happen. They don't want it to happen, but as you see in general, it pretty much doesn't happen very often if at all. Interesting. That's been one of the biggest pushes toward having larger water heaters if there's storage or tankless water heaters with big burners. People going the tankless route. And then the third question, having to do with the population in your household tells me that we've got a reasonably typical crowd. The U.S. average home is somewhere around 2.7 - 3 people per household, and we average out just about there. So looks like we've got a pretty good group to work with. Let's get going.

Next slide:
Is my screen live now?

Lindsay Parker:
Yes, it is.

Gary Klein:
Super. Alright. Integrating the components into an effective system.

Next slide:
So what reduces hot water use? Insulating the pipes, put the end uses closer to the water heaters. Lower flow rate plumbing fixtures. Lower volume plumbing appliances. Using waste heat running the drain to preheat cold water. Truly instantaneous water heaters. Warmer incoming cold water. Meaning everyone has to move to Phoenix. Or anything else? You know, the things that reduce hot water use are these.

Next slide:
What increases hot water use? Uninsulated hot water supply piping. And the reason for that is that more uses start out with colder water. End uses further from water heaters. More volume to clear. Lower volume, lower flow rate plumbing fixtures actually increase the waste while waiting for hot water to arrive. That's a counteractive effect of lowering flow rates. Instantaneous water heaters that aren't, which means that cold water runs through them while they ramp up the temperature. That defines most of the instantaneous or tankless products on the market today. Colder incoming water. It increases the percent of hot water that's in the mix. as well as having to have a greater delta T to heat the water, from an energy point of view.

Next slide:
What increases customer satisfaction? Instantaneousness. Meaning hot water arriving pretty darn quick. And I would say in our example, the 30- to 60-second range is not pretty darn quick. We sort of learned to put up with it. Continuousness, meaning not running out in your shower. You'd like your teenagers to run out in theirs, but not yours. Hot water systems that are predictable and easy to learn. I would observe that today's hot water distribution systems effectively have random delivery times. Sometimes they're very short. Sometimes they take a long time. That could be anywhere in the house or at the same tap, depending on whether they're the first or second user in a row. Randomness drives people nuts. They're not predictable and therefore in our subconscious we just -- I think we just tend toward behaviors that say, well, I'll go do something until I'm ready to come back, and we'll see if I get lucky then. Plumbing fixtures that provide rated flow even at low pressures. We talked about that last time having to do with the idea of pressure compensation so that it doesn't matter what the local pressure is at any given hour of the day. Plumbing appliances that do their job with lower amounts of water. The key is if you're a dishwasher or washing machine is to clean the dishes and clean the clothes, then use less water and energy to do it. Devices like that are available. And then lower energy bills for their hot water. People really don't want to pay a lot for all of this.

Next slide:
So the ideal hot water distribution system has the smallest volume between the source of hot water and the fixture. Sometimes the source of hot water is a water heater, and sometimes it's a already heated trunk line. That might be with a circulation move or it might be a heat-traced trunk, but you've got to get the water from somewhere. And those are the three sources defining codes, and logical sense makes that true.

Next slide:
Here's the challenge. Deliver hot water to every hot water outlet in any building wasting no more energy than we currently waste running water down the drain, and wasting no more than one cup waiting for the hot water to arrive. How would you do it? Think about the answer to that. Turns out, we have found five ways. We've never found six. We keep looking for six. So if you've got ideas that might useful, send us a message and we'll see if they create the sixth.

Next slide:
But the key is this. If you want to waste no more than one cup waiting for the hot water to arrive, what's the maximum amount of water that can be in the pipe that is not usefully hot? And for purposes of this discussion, assume that you want to be sure that the water's hot enough to take a shower in. In my experience, and others I've asked, in general people are willing to wash their hands in pretty much any temperature water, but they're not willing to take a shower in those same temperatures. So I use the shower-taking temperature as the usefully hot water for purposes of design. The answer, if you want to waste no more than a cup, you can't have more than a cup to clear out of the pipe. Can't be more than a cup. And in fact, it must be less. Now, a cup isn't very much.

Next slide:
It's not very many feet. We'll talk about that a little bit later. And then the other question is, if you want to waste no more energy than you would have wasted waiting for the hot water to arrive while running down the drain, how much energy can any alternative consume? Well. The answer for that is, no more than was originally wasted. So what percentage of a typical hot water -- a daily hot water use pattern is wasted while waiting for hot water to arrive? We've got some evidence that waiting for showers is on the order of 20 to 25 percent of the length of the shower itself. And so if a shower is being taken at two gallons a minute -- not a bad guess -- and the average shower in the U.S. is around eight minutes, that's 16 gallons in total. Of that, 20 percent -- one-fifth, right? -- 25 percent, so it's like somewhere around three to four gallons of the shower is wasted waiting for the hot water to get to the right temperature. Some of that was structural and some of that was behavioral, and in general, from we can tell, if people wait a little while to get hot water, they go do something. They come back when they're ready. Behavioral waste is generally bigger than structural waste, by roughly a factor of two. So what the split looks like, from our studies of this, it's somewhere around one-third of that 20-25 percent is structural waste, two-thirds of that 20-25 percent of the shower event was behavioral waste. My goal is to help you all design hot water distribution systems that drive the structural waste down to very small numbers and make the houses exceedingly predictable in hot water delivery so that in fact we can explain to customers, this is what you should expect and here's the behaviors you might want to try.

Next slide:
So normally we would do some interactive exercises to demonstrate how to deliver hot water in every fixture with less than a cup and evaluate the hot water distribution system without being able to see the pipe, but we're on a webinar. We're going to do something else.

Next slide:
So next question. The maximum allowable volume between the source and the use. This is what we have to design to in order to get the performance we're after. So the DOE Challenge Home and the EPA WaterSense spec says 0.5 gallons from any source of hot water is the maximum that can be in the pipe, and it also says that a second piece is that when you test for it, no more than six- tenths of a gallon can come out before you see a 10-degree rise in temperature above the base household ambient water temperature. So, but the maximum allowable volume in the piping between the water heater and the fixtures or from a recirc loop to the fixtures is 0.5 gallons.

Next slide:
So here's a table that will actually be in the IECC commercial chapter starting in 2015. And it's easily referencable and readable. It shows that the maximum allowable piping length in feet to convert 0.5 gallons to feet, is in this table. We've created a nominal pipe size. We've looked at nominal pipe sizes from quarter-inch up to two-inch. We've got a nominal volume for each nominal pipe size to make it easy, saying all materials are sort of the same; they're not exactly the same but for purposes of this, they can be looked at that way. And then you've got this from the water heater to the fixtures or from a recirc loop to the fixtures, because we're doing them separately in the code. So for EPA WaterSense and DOE Challenge Home, we're going to use the 0.5 gallons portion of the table, and it's here. So the Challenge Home says, from any source of hot water, in the two heads of the table, to the fixtures, the maximum can be 0.5 gallons. Well, let's imagine we're using a three-quarter-inch pipe. You would get a maximum of 21 feet. If you were using half-inch pipe, you would get a maximum of 43 feet. If you're using some three- quarter and some half, you have two ways of doing. You're estimating according to the code but for purposes of the Challenge Home, I would recommend using the volume calculation method, which allows you to take some of the three-quarter and some of the half, and get an overall total length that gives you more flexibility in the layout. Mostly, it's going to be very difficult to design houses so that you can deliver hot water within a half a gallon in the piping from the water heater to each fixture. It's possible. It's doable, and in fact I've seen some houses and designs that make that happen, but it's tough. Now, if you go to three-eighths, we've limited the length to 50 feet because the plumbing code says you can't have more than 50 feet from the source to the use. And quite frankly, in three- eighths and skinnier tubing, at the flow rates we're discussing, the extra pressure drop through this greater length causes you trouble, and I recommend keeping it shorter anyway. So this is the table. This is what you're looking for. What we need to do is to evaluate designs to see how that might play out.

Next slide:
So, since I don't have an exact floor plan and every floor plan is a bit different, I want to teach you the logic of how to look at it. I highly recommend you follow along on a piece of paper with you in your offices and draw yourself a rectangle. This represents either the floor plan of say a single-story house or it might be the floor plan from the water heater to the furthest fixture, which may or may not be the furthest end of the house. So there's length, and there's width. You've got plumbing fixtures. We're going to use this rubic later. The plumbing fixtures could be anywhere in this space. Water heaters could be anywhere in this space. But imagine a water heater was down over here in this corner. It might be inside in a basement or it might be out here in a garage. Those are both pretty typical. And the furthest plumbing fixture might be over here or it might be over here. We're going to go through some of those examples in a minute. So a couple of things in plumbing. It rarely runs diagonally. You need to determine what is the rectilinear path from the water heater or the recirc loop to the plumbing fixtures and appliances. We're going to work through the case of water heaters to the fixtures first. Length times diameter equals volume, and you need to determine how many paths or zones of plumbing there are. OK. All of these tell us how we're going to improve the performance of whatever we've got, given that we're not going to be able to change the layouts.

Next slide:
If you're able to change layouts to make a difference, we can show benefits by doing that. So here's the one-story example: 1,200-square-foot house. Length times width, length plus width plus vertical, which is the height. Not exactly the height. It's a little bit more than that. Would be 40 plus 30 plus V. So 70 plus V is the example I want to use. Vertical has to do with getting up out of the water heater or down below the water heater, and back up over the ceiling if you've got single-story, or down under the crawl space, or up the ceiling in the attic. You've got to follow your vertical beat. The shortest vertical feet tends to be approximately the height -- the floor-to-ceiling height of say roughly 10 feet. That's the best case. The worst case is, in a single-story house, it can be as much as two times the floor-to-ceiling height. Roughly, it's one and a half times the height of the floor to ceiling. So around 15 feet of extra length. Now, here's a one-story, 2,400-square-foot house, which is 40 plus 60 plus V. So the floor plan, the area is double but the worst-case positioning from the water heater being in a corner, and the furthest fixture being diagonally opposite corner would be 40 plus 60 plus V. Or 100 plus V, or 115, roughly speaking. One story, here's a 3,600-square-foot house. Significantly bigger. But it's only 130 plus V. But here's the kicker. If you put the water heater over here somewhere and the furthest fixture over here somewhere, and the odds are that furthest fixture is going to be a master bathroom and it's going to have a big tub, there's a pretty good chance you're going to have a one-inch pipe from the water heater all the way to that fixture. And so not only have you gone up to 130 feet, which is roughly twice what it is for a 1,200-square-foot house, you've also doubled the diameter, the internal volume of the pipe by going from three-quarter to one inch.

Next slide:
So now, the benefit of multiple stories. A one-story house. We've just looked at 1,200-square-feet, has 70 plus V. A two-story house, where you're stacking one floor on the other, still has 70 plus V as the worst length distance between the furthest points. And if you have a three-story house, it works out to be 70 plus 2 times H. It might be a little worse if you put this water heater in the attic, but that's basically what it looks like. So, stacking things takes, makes the plumbing lengths shorter. That's a good thing.

Next slide:
One-zone plumbing, one-zone hot water distribution system. So here's some examples. Let's imagine we put the water heater in the corner. It's either in the basement in a corner, or it's in the garage in a corner. And you go to the furthest fixture. You get length plus width plus V. Here's another example. That shows you that the path to the furthest fixture can go multiple ways as long as it doesn't backtrack. The distance to the furthest fixture from the water heater doesn't really change. I can take any basic path as long as I'm not being silly, and I'll have the same approximate lengths. Now here's a case where I was able to put the water heater sort of central in the garage as opposed to, or central in the basement on one wall, and I made my design such that the path to the furthest fixture -- plumbing fixture -- is straight across the building. That doesn't always happen, but something close to it can happen. And here's another case where I'm going across the middle of the building the other way. The key is that we need a methodology to calculate what's going on in the plumbing. And the idea is to give us that method.

Next slide:
Now, here's another one- zone distribution system. In the previous cases, the water heater -- well, the first two cases here, the water heater is in one corner and the furthest fixture was diagonally opposite in the farthest corner.

Next slide:
Now, in this case, we have the plumbing fixture halfway up the wall, on the opposite wall. But it's still all the way across the house. So it's length plus half times width plus V. Here's where we put the water heater in the center, and the furthest fixture is in a corner, and all fixtures are on this zone. They're all in this space. Or they're just off on this side of this path. The key is the path. Here's a two-story -- you're looking at a two- story with above a basement, or three stories above the grade. Water heater in one corner and the fixtures in the middle on the opposite side. It's length plus width plus two times H. Very straightforward. And here's where you've got everything in the center and you have got stuff going off the central core. We used to design buildings this way. A lot of households have this. We seem to have gotten away from this basic plumbing design, and I think we ought to think about getting back to it.

Next slide:
Alright, here's a two-zone plumbing system. I put the water heater in the center, and I had two different pathways to get to where I'm going. And the length in both cases is 0.5 -- yea, it's 0.5 L. ... I think I've got it a little wrong here. Looks like it's going to be width plus half of L plus V times 2. My apologies. Here's another case where I've got two zones. Length plus width plus volume, plus vertical. Going here. Length, width, and vertical, plus length and vertical. I don't have any width to worry about. Here's a case where you've got a multistory building. And you've got one that goes up and one that goes over and up. And you can see that I've got to figure out where to put the fixtures. Follow the map. Here's another case. Another two- zone system. I'm basically going from the center off to the right, the center off to the left. Got to go by vertical. That doesn't change. But I'm doing essentially the same thing in two different directions. Well, you need to decide on the plumbing. This has more feet of pipe in it than the single-zone system does. You've also created two potential problem directions. Multiple zones can be beneficial, and multiple zones can hurt you if you don't plan the paths right. The most extreme example of multiple-zone plumbing systems would be a home run manifold system. There's one trunk that's relatively short, and there are twigs going off to each fixture that are relatively long. Each one is its own zone. Because by definition in that methodology, there are no branches off of those twigs. That makes sense. You have branches and then twigs coming off of them. But the way that plumbing system is designed, manufacturers hope you to install, is to have one central core manifold and then relatively long twigs to each fixture. Each twig represents its own zone. And very difficult to retrofit to later.

Next slide:
Here's another case. Put the water heater in the center and you create a four-zone plumbing system. Well, notice that my feet of pipe have gone up, not down, by putting the water heater in the center. The key to centralizing water heaters is to centralize them relative to the fixtures, too. You've got to reduce the length to the furthest points, as well. Then it might make some sense to think about home run manifold system. But in all cases I think we can find better ways of doing this. Here's another one. We've got multi-zone systems. This is a two-zone system. Well, sort of. It's actually a four-zone system where you share a pathway. You're sharing a pipe. But that's a zone, that's a zone, that's a zone, and that's a zone. Here's another two-zone system. Water heater on one side, another water heater on the other side, and I've got each one as a zone. Well, I've got -- I've seen builders do this. They put water heaters on one end of the house, the other end of the house. And that makes a lot of sense. But we still have to think about the volume in the piping from the water heater to each of the fixtures in that zone. And then this is another case where you're putting in multiple water heaters near each of the zones. Four-zone system with four water heaters. But notice how I've cut the feet of pipe out by dramatically closing the gap between the water heater and the fixtures. That's the key point here. You've got to figure out the volume. And I'm going to guess that the builders on the call are going to say, I can't afford four water heaters. I can barely -- I barely want to spend my money on one of them. Oh, and the consumer's going to say, why do I want four water heaters to maintain, or die, or need fixing? It's hard to see this solution in single-family residential, although we'll see people who want to do it, and I think we should encourage those who are interested in doing so to do a good job with it.

Next slide:
Here's the vertical case. That's a three-zone plumbing system. And again, ooh, this is the water heater in the attic case. Anybody on the call from places like Houston, would like to do this in Houston. It's the water heaters up in the attic. And then you've got to bring them back down again. And the best case of coming down is two times the height. And the worst case is to get back down to the third -- back of the first floor, and it's around three times the height of floor to ceiling. So that adds 30 feet in vertical, plus whatever horizontal distances you have to the furthest fixtures. Alright.

Next slide:
On to performance metrics. I'm going to suggest to you that the first metric is, that it has to be greater than or equal to 110 Fahreinheit at the tap and people will consider it hot enough to shower in. You can probably get away with 100 to 105, but 110 means you've got a little bit more ability to mix down, so we're going to use 110 as our target point for discussion today. Not a 10-degree rise above ambient. 110. That's what people want. That's what they expect. That's what we're looking for. Now, the volume until hot, the goal that I have is always to waste no more than one cup after you turn on the tap. I'll settle for two or three cups, maybe four cups just because of some practicalities in the construction. But my goal is always to aim for a cup and settle for a bit less. And then the time to tap, I want to make sure it's consistent and small. Less than a second is possible but it looks to me like it's very energy-expensive, and we're not going to assume we're in it for that yet. Less than five seconds is very buildable. I've asked lots of people this question, and everyone would love to have hot water show up everywhere any time they need it within five seconds. And according to ASPE, it is acceptable to provide hot water in less than 10 seconds.

Next slide:
Here's the Builders Challenge, Challenge Home, temperature, 10- degree rise, by 0.6 gallons. For example, 70 degrees rises to 80 degrees Fahreinheit. That's not hot enough to shower in, but if the hot water is coming soon, probably. You get evidence of it, in that if things are moving along properly, you'll have evidence of it in that first 10-degree rise. And if you feel that rise happening, you know it's going to come reasonably soon thereafter. The question then is, how much longer is it going to take for the 110 to actually arrive? And then the volume until hot comparison, what we're saying is, 0.5 gallons in the pipe, 0.6 gallons until 10-degree rise, and the question is, how much more volume will come through until you get the hot water? OK. It's going to be at least a gallon before it gets there. And then finally, the time to tap. The Challenge Home method, using EPA WaterSense procedure, allows you to put in trunks and branches with effectively random times to tap and random volumes to tap depending on where you are on the path to the furthest fixture. There is an exception. If you have 0.5 gallons, the same length, the same volume coming from a twig, from a circulation loop or a heat trace trunk line, you will get time to tap being much more consistent. But then the question is, how long is that? And so you end up being, to meet the EPA WaterSense, if you want a maximum of 10 degrees Farenheit 'til rise, you get about 18 seconds for that to happen. You'll have two gallons a minute. At one gallon a minute, it will be 36 seconds and the other one -- half a gallon a minute, it will be over a minute. So my question to everyone on the phone is, is this acceptable? Yea, it meets the Challenge Home spec. I got it. I understand that. But my question is, I want to turn it around: Is that what you want to sell your clients? Is that what you want to be acceptable in the home? And I'm going to suggest that people want hot water to show up much more quickly, and I mean 110, in much more quickly than 18 seconds. They'd be excited if it happened everywhere. And the key is that flow rates are not going to be two gallons a minute; unless you do things to ensure it, they're going to be closer to one gallon a minute. They're not going to be happy at 36 seconds. So we're selling a better-than-average product, and I think we have to push pretty hard on better-than-average hot water distribution. Now, to be fair, the Challenge Home spec, based on EPA WaterSense, is way better than waiting two to three minutes to get hot water at the extremes of the house. It cuts out the big extremes. But I'm not sure it's a target I want to aim for, for typical performance in an above-and-beyond home.

Next slide:
I brought this back from the last presentation. How long should we wait? According to ASPE, everything should be in the green. So at two gallons a minute, two and a half gallons a minute, green would be, oh, much less than a half gallon. Right? We have to be in on the order of a quart, which is half the Challenge Home spec. So I think we should be designing systems assuming we're having at one gallon a minute, the flow rates because that's the trend that people are aiming, heading toward, and in fact based on the data we shared last time, typical hot water use happens at about a gallon a minute. So we ought to be designing our systems assuming a gallon a minute at the plumbing, and if we have it higher than that, well, performance will be better and no one will complain. So that's how I work my logic when I do design.

Next slide:
And from the last presentation, again, just to remind people, there's more waste than the volume that is in the pipe until the hot water gets there. And you really do have to measure for that. So it works out.

Next slide:
Now, let's use this and see what we're going to do and show the problem slightly differently. At two gallons a minute, half a gallon in the pipe would be 15 seconds. But it takes longer than that for the hot water to actually clear. So it's going to be more like 18 to 20 seconds, maybe 25 seconds, until it completely clears out. And then at one and a half gallons per minute, it's still longer at two -- one gallon a minute, it's still longer. And for those of you that want to put in 0.5 GPM aerators in bathrooms, people are going to wait a long time if you've got a half a gallon to clear in the pipe. OK? Remember these numbers. Follow the numbers.

Next slide:
Alright. Here's another example of something that might be of interest to some of you. If you're in southern California, we can arrange to have a training session at this facility. This is at SoCalGas' facility at the Energy Resource Center at Downey. They've created a hot water demonstration lab. And on this wall, back here, are three different storage water heaters. There's a boiler over in the corner. Outside -- this is southern California, after all -- there are three tankless water heaters. And further out, there's a storage tank for a very large solar thermal system that was put in some years ago. You can see these two carts. They're on wheels. They are somewhat portable. There's a typical sink and a typical shower. And over here is a prerinse spray valve for commercial kitchens, and a dishwasher that we would see typically in a home. And this allows us to connect the water heaters to the uses and measure things as it's moving through the path. And that's one of the exciting things about this training center. We're actually able to demonstrate performance of these sorts of things and answer questions about performance technically in real time. Someday we ought to do a webinar where we're broadcasting what's happening in this room through the hour. It's pretty fun. We can do a lot of good stuff.

Next slide:
So we've created an experiment, an experimental rig, if you will, that's replicatable. We've created a flushing and priming station that allows us to have hot water enter when we want it to. Cold water can be used to flush out the pipe when we need to. And this is the drain that allows us to set up the experiment so that our hot water gets to this point every time for every experiment, and we're starting with everyone at the same place to make it fair. Then when we open up the experiment, we go through a plumb meter, a pressure gauge, and a temperature sensor. We've connected a length of pipe that we're testing that currently is lying on the floor in the classroom.

Next slide:
It runs around and it comes back over here, and it's the temperature's measured, the pressure's measured, and then the water goes out and into the sink over here, which is our flow rate control. OK?

Next slide:
Here's an example of an experiment we ran, and we were able to watch in real time, record the data, and then plot it. And so what we have is the green and blue line are the same here. We started the experiment, the temperature is being measured at 0.1. It goes up through, it climbs very quickly at 0.1 but it's very close to where the source of hot water is. This is a very classic curve. And it settles out asopotically at about 130, which was the temperature the water was set at. Somewhere about 58 seconds or so into this event, the water temperature started to rise. OK? Here we go, it started to rise. And it took us 90 seconds roughly until we had 110 Fahrenheit. Well, how much water was in the pipe? There was 75 feet of uninsulated three-quarter-inch pex. Remember, 75 feet is the volume in the pipe, roughly speaking, from the water heater to the furthest fixture in a 1,200-square- foot home. Again, not a big house. And you would be able to predict that it would take about 90 seconds to clear out that one and a half gallons, roughly, and that's what it's going to take until it rises in temperature to get to this point. OK? Is that acceptable? Well, it doesn't meet the Challenge Home spec at all. So we were there having a discussion about what ought to happen for the next round of Title 24 building standards in California, the energy piece in particular. And one of the folks in the room representing a bunch of the builders suggested that perhaps we ought to think about well, delivering hot water within 15 seconds. Because they felt that it would be possible for a builder to sell the value of that. I could tell my customers that you guarantee hot water delivery within 15 seconds everywhere in the home, any time you turn on a tap, that'd be pretty good. And it is buildable.

Next slide:
So we set up an experiment to do that. It took us about a half an hour or so to get ready and do the experiment. And this is 10 feet of uninsulated half-inch pex. Again, very typical of what would be used. And we were able to get the hot water to -- again, same experiment, climb to this point. Hot water got to the temperature sensors in 12 seconds. The fixtures were a few feet away. We hit our 15-second goal or pretty darn close to it with this method. Not bad. It is buildable. OK?

Next slide:
How are we going to do that in our homes? Mostly, you're going to ask me or people like me to figure out how to do the floor plan -- the layout of the plumbing to match the floor plan that you're working with. You can spend a lot of time and effort getting the floor plans that you think customers want and will buy and have good flow, walking around the building, they're good from that point of view. We don't want to change any of that. So we now have to figure out a plumbing system that is going to make it work for you. In most cases in order to meet the DOE Challenge Home spec, and to provide hot water in short order to consumers so they're happy, you're going to end up putting in a recirculation system. There are six ways to operate the controls of -- or no controls on a loop, and there are basically only six. We've never found seven. There's some variations and some nifty things that are coming along now. But basically the categories are these. Thermosiphon as a gravity loop. No pump 24/7. In order to work, it loses heat. As it loses heat, the cold water settles, the warm water rises, the water moves around the loop relatively slowly. But there's temperature drop, and it's the temperature drop times the flow rate that the water heater ultimately sees and has to reheat. Then you can have a continuously pumped system, 24/7. Move the water around. It's controlled. Yes, it's a pump. But you're in control of it. So now you have the 24/7 looping losses plus the pump energy loss. Well, I don't like that. I'll put a timer on it. Well, which hours of the day are you going to do? How are you going to match it to people's schedules? People's schedules change. Lots of things are difficult to do with timers. And you can have temperature control; here I mean an aquastat, where a bandwidth temperature sensor tells the pump to turn on and off based on the temperature drop over that bandwidth. When it reaches a low, the pump turns off, or when it reaches a high, it turns off. You could have time and temperature control, where you're using both timers and aquastats in combination to limit the hours and then the aquastat will tell the pump to turn on and off within those hours of operation. And then finally, there's demand control. Coming up in 2015 for both residential and commercial energy codes for the ICC, demand control in some fashion will be required. The looser level of demand controls will be -- end up operating on the order of three to four hours a day, maybe as little as two. The best of the demand control systems will operate well under an hour a day. So given the same plumbing layouts, where you put the recirc loop, and keeping the branches to their twigs to the fixtures the same in each case, all of the systems will waste the same amount of water at the beginning of a hot water event. Right? You're designing a loop to be wherever you choose to put it. You're just changing the control strategy of the pump if you have one. And the difference in these systems is the energy it takes to keep the trunk line primed with hot water. So this is an energy program. We want to keep the energy consequences of the loop as small as possible.

Next slide:
So what are the operating costs of loops? You've got pumps. You've got heat loss in the loop. You've got maintenance. And it turns out that 90 percent of the cost is heat loss in the loop, 10 percent from the pump operation. And you could measure the lengths of the pipe and the insulation and the environmental conditions and calculate the loss, or you could measure the flow rate and the difference in temperature between the water heater leaving and returning.

Next slide:
So here's the calculation method. I'm going to zip right through it. You can read all about it later. Here's a chart that looks at how to calculate it for different temperature drops and different flow rates. And you can see if you've got a five-degree drop, it's going to end up costing you about 292 therms a year, which by the way is, for those -- gas water heating -- is at least double the typical, average household's hot water use. OK? That's probably not what people wanted. And if you have a bigger system, right, where you have a five-gallon-per-minute pump, and a 20- degree delta T, you could be 5,000 or so therms a year. Same calculations here for electric.

Next slide:
When do you not want to operate a circ pump? Well, let's see. When you don't need water. Well, when you're not there or when you're sleeping or doing something else. If you remember, people use hot water less than an hour a day on average in homes in the United States. It's concentrated. It's lumped together in patterns of use that change daily and weekly. When you're using hot water, you don't need the circ loop running because in fact the hot water's coming through the pipe all by itself. The only time you want to operate a pump is just before you need hot water. Use demand control circulation. That's the one that gets you the best control of when the pumps need to run, and it gives you the greatest ability to adjust to the schedules as they change daily. This is a summary table showing various choices of using natural gas or electricity for the water heating. It's got some examples of what we're controlling. The number of feet, we've got some basic assumptions that we've built into the model. Very simple spreadsheet-based model. 24/7 down to two hours a day for the standard recirc loop. Demand control priming is on the order of 25, sorry, 15 minutes a day. It is significantly less hours of operation and therefore much less heat is moving through the water heater to make that priming possible. It's the most efficient strategy we have seen so far. As I mentioned earlier, there are manufacturers coming out with variations on demand control strategies that use what they call smart controls to sort of watch your behavior patterns and predict when to prime the pumps. They will be better than most any of the other control strategies that are typically available for circulation. But in order to get close to the energy requirements of demand, they're going to have to push the numbers down way, way less than two hours a day. And I haven't seen evidence of that yet in the tests I've seen. But I'm hopeful. We'll see what happens.

Next slide:
One other item I want to cover today is drain water heat recovery. Basically it's a method of capturing waste heat that's leaving the building, running down the drain, and I would like to capture some of that heat and reuse it before I let it leave the building. This is very clever. It's buildable. You need height to do it. So those slab-on-grade houses, one-story, this is not going to be particularly useful for most of us. People who have vertical height and master bathrooms upstairs, there's room to work with. These are a very, very good idea to capture waste heat.

Next slide:
Basically, you connect the cold water line toward the bottom, on the way to -- either to the water heater or to the shower. You take out the pipe at the top. You send it to the water heater or to the shower or both. And you end up preheating the water while you're taking a shower. Hot water is running down the drain, say 100ish, 95-100ish-degree water's running down the drain. Cold water's coming in, and you're preheating the cold water while you do that.

Next slide:
There are two methods of using -- doing water heat recoveries. One is called balance flow, where you're preheating the cold water that enters both the water heater and the shower that's being used. And unequal flow preheats the cold water entering either the shower or the water heater. So in California, where we have slab-on-grade construction and the water heater's in the garage, and the master's at some other distant point in the house, it probably makes sense to use an unequal flow path. Potential savings are pretty good, 40 to 80 percent of the temperature drop for a given event. Balance flow saves more than unequal flow does, but hey, it's better than letting the water -- the heat -- leave the house. And you need to pay attention to everything in how it works as a system, how does it impact temperature drop, all sorts of stuff needs to be paid attention to.

Next slide:
Now, as a reminder, because we're going to wrap up pretty soon, if you've got questions for today you'd like me to answer today, I need you to send them in soon, so we have time.

Next slide:
In the meantime, incorporating high-performance hot water systems into our buildings.

Next slide:
Based on the last couple of seminars and your own experience, what best practices can you come up with? What do you think should become code? Which codes? What do you think should be included in programs like HERS and ENERGY STAR or LEED or Challenge Home, whatever it is? Each of the practices -- you know, where do you want to go with this? So over the last several years, I've been working on this nationally, as many of you know. And we've come up with a list of best practices.

Next slide:
The first best practice: Understand the hot water use patterns for each occupancy you're dealing with. We covered those patterns last time, for residential use. On average we need to assume that hot water use is essentially a random event with enormously large variations in volume and in daily volume of hot water need, hot water use, and it's within each household. Also need to assume that the flow rates are going to be on the order of two and a half gallons per minute or less 95 percent of the time. Peaking flows are very, very rare. So, we should be using that to adapt what we do for houses. The other thing that I think we have to pay a lot of attention to is that if we design the hot water system for two somewhat active seniors, and the house is next purchased by a family of five, with you know, growing teens and all that stuff, and lots of activity and sports, on three days a week, whatever it is, we're not changing the water heater and we're not changing the plumbing. It needs to work well for each future occupant of the home. That's been one of the toughest design pieces we've worked on over the last year, is it needs to perform well under a huge variety of use conditions. We need to understand the services that hot water -- of hot water desired by the occupants. All occupants have said to me they want it to be instantaneous and continuous. They expect it to be safe and reliable. We need to provide these services in the most water- and energy-efficient way. And from the point of view of new construction, none of this can cost much if anything. We've got to figure out how to do it within our typical budgets of construction. And I'd say that's really true -- exceedingly true -- for houses that are in the U.S. median home and smaller categories. By the way, instantaneousness is more important that continuousness. You've documented that today. Mostly we don't run out of hot water very often if ever. So we need to focus on getting hot water delivered efficiently.

Next slide:
But continuing the best practices. Locate the sources of hot water close to the uses. Keep the volume from the sources to the uses small. The fact that you put the water heater next to the use doesn't mean you used the right diameter pipe. We need to use the right diameter pipes. Particularly since typical flow rates are lower than they used to be. One of the things for the support folks on the call to help get information on for the builders, what are the flow rates that are typical today for washing machines and dishwashers that meet the ENERGY STAR protocols. It will be very interesting numbers to get. Minimize the pressure drop and optimize the velocity of the piping. Hard elbows -- hard, 90-degree elbows -- are bad. Putting three or four or five of them in a row within a few feet of each other, or sometimes a few inches of each other, really bad. When you can bend the pipe, do it. Make a wide radius sweep. It's better. Really, really important. We're going to demonstrate that at that lab in SoCal. We're going to make up an experiment to show this.

Next slide:
Insulate the hot water piping. There are no codes in the United States that I'm aware of that require that you insulate all hot water piping for residential applications And I just don't get it. We insulate all of the walls in the building that are exposed to -- that are a part of the thermal envelope. Hot water temperatures are always different than house temperatures by a minimum of 30 to 40 degrees. I just don't understand why we don't insulate them all. Oh, it's too expensive. It doesn't pay out. Uh-huh. I've had that debate. Remember the use patterns. Ninety percent of all hot water use happens within an hour. Pipe insulation pays out for all of those uses where hot water -- the patterns are within an hour. It pays out two ways. It gets the hot water there quicker. A little bit, not much. Depending on the environment, it could be a big number, like under slab. Or if through a crawl space. And it also keeps the water in the pipe hotter longer so that more events feel like hot-start events rather than cold-start events. And that effect starts to be noticeable in the 20 minutes between -- in the 10 to 15 minute and beyond timeframe between uses. And there are 30 percent of all hot water uses that are like that. So provide a method to prime trunk lines with hot water shortly before the use. You want to be in control of when that happens so that it can adjust to your schedules. Utilize hot water-efficient fixture fittings and appliances. Plumbing fixtures and appliances are not the first things to do; they're in the middle to the end of this list of best practices, because if you don't get the plumbing right, people will be upset that it takes longer to get hot water than it used to. You'll have more temperature drop over a length. It will be less efficient than people predict. Yup, you'll use less water, but you won't have happy customers.

Next slide:
Alright. More. Capture waste heat from water running down the drain and use it to preheat the incoming cold water. Combine the energy requirements for water heating and space heating into one thermal engine. We have not talked much at all in this session, in the last two sessions, about the water heater choices, but efficient water heaters -- 90-plus water heaters -- cost a bit more than standard efficient water heaters do. For electric, we're talking about, you know, heat pump water heaters versus standard electric storage or tankless. Each have COPs of 1, and the heat pumps have COPs of 2 or more, typically. Great. They cost more. It's a problem. But what if you could use the water heater to be the thermal engine for the house? So instead of having a furnace and a water heater or a furnace and an air conditioner and a water heater, we were doing something like -- or a boiler and an extra water heater, all of those things where we have two things to do stuff with -- maybe we should think about combining them into one thermal engine. Well, much of the stuff that's out there today is fairly expensive. There aren't a lot of options. And it's harder to get installers to know exactly what to do because the equipment is typically not packaged. We're working to change some of those things. Anybody'd like to talk with us about what can be done today, we'd be happy to have that conversation. And then you need to select water heaters or boilers matched to the uses and patterns of the hot water use. You've got to pick stuff that's going to work over the wide range that we've talked about. And if you're going to go to the trouble to buy one of these fancy water heaters, you better think about how to maintain it for a long time, because it was expensive to begin with. All of that's part of the package.

Next slide:
One last piece here before closing up and taking your questions. Most of us are pretty good at what we do technically. But we often run into frustrations in our work that have nothing to do with our technical knowledge. There's a list of books here that I have found extremely beneficial in my life. I want to pass them on to you. The first bunch of books, from "How to Win Friends and Influence People" down to "The Go-Getter" by Peter Kyne, are all about better communications and focusing on how to be all better as a, better as a human being, both at work and in other things. "The Richest Man in Babylon" is about money and how to live within your means. It was written in 1926, so if you think there's investment advice that was useful, it's not about that.

Next slide:
Alright. Any questions from the audience today that we need to cover?

Jamie Lyons:
Hey, Gary. Thanks. This is Jamie Lyons, again, everybody. Let's take a look at the questions here, Gary. And I'll queue a few up. There was one that I actually might just take, and I'll read it here. Is there software or a spreadsheet available to use when designing these systems? That's a great question. And DOE Challenge Home has been working with the EPA staff for WaterSense, Jonah Shine, specifically. And working on a basic spreadsheet-based design tool to help estimate stored volume and plumbing systems. So look for something on that to come out here pretty soon, in 2014. We certainly realize some basic design tools might help our partners.

Gary Klein:
So I would like to also take part of the answer to that. The -- we have MASCO to the EFL program helped develop a calculator that allows you to plot the plumbing as you walk it around the building. Vertical up, vertical down, north, south, east, west, from drawing point of view, allows you to track where you put the plumbing and do "what if" cases. That tool is available, as well. If you contact me, I'll get you in touch with how to use it. We've also ... you'll get comfortable with doing this, if you choose to go down the path of calculation. And what you'll end up finding is that the fundamental decisions -- mostly plumbing is three-quarter and half-inch piping, sometimes it's three-eighths and sometimes it's one-inch. That depends on your code jurisdiction. Depends on some of the fixture sizing you've got. But if you start getting comfortable with three-quarter-inch trunks and half-inch branches and twigs, you can start estimating this stuff pretty well. The logic stuff we described earlier is a very useful overall way to look at it.

Jamie Lyons:
Thanks, Gary. You mentioned different pipe sizes. There's a couple questions regarding pex. What's your recommendation for insulating pex? Many contractors are reluctant to insulate flex tubing despite the code. And then a related question is, somebody relayed that it can be difficult to find three-eighth-inch insulated pex.

Gary Klein:
Right. OK. So the question that's being asked is, plastic -- pex being one of the most commonly used, the other is CPVC -- is a better insulator than copper, right? Well, not exactly. Our research shows very clearly -- thousands of data points -- show very clearly that when you have a room temperature-based surrounding air system, which is the best case you'll have the piping in, we will end up with heat loss that's more with copper than if you have pex or CPVC. And I know that's counterintuitive, so let's walk through it. The first piece is that copper is more conductive, so any heat that gets from the inside of the wall of the pipe to the outside of the wall of the pipe happens quicker in copper than it does in pex. I agree. However, because of the nominal pipe size rules in the United States, the outside diameter of all of the different materials is essentially the same. And so what ends up happening is that the conductive losses are essentially the same for each of the pipe types. So once the heat gets from inside to outside, it's going to act very similarly due to convective losses. Well, the third term for heat loss is radiation. And it turns out that because copper is a conductor, it turns out it's also a pretty bad radiator. Plastics are lousy conductors and they tend to be good radiators. So the difference in the terms is happening in the radiation effect. As best we can tell from our research. And the heat loss rate of plastics is greater than that of copper for all diameters that we have tested up to one inch so far. I know that's counterintuitive. I get it. The reason we've written rules the way we have across the country is that you should insulate all piping that hot water flows in, regardless of the material, is because of this research. So, the question: Should you insulate pex? The answer is yes. Should you insulate CPVC? Yes. The 2015 building code for ICC residential will say all three-quarter-inch and larger diameter piping shall be insulated, plus any pipe that runs through that environment of whatever diameter. Simpler than the 2012 code, but it doesn't insulate all the hot water pipe. Quite frankly, if you're going to go to the trouble of insulating it, I recommend insulating all of it. I think we could have a code -- we could also allow you to use the building's insulation materials as pipe insulation, as long as you're surrounding the pipe, I think it's fine. So. There we go on insulation. Next question.

Jamie Lyons:
OK, thanks, Gary. We have a number here, so we'll try to get to a few more. Here's one regarding drain water heat recovery. Is there a difference between drain pipe type, cast iron versus PVC?

Gary Klein:
They act differently as drains, but the drain water heat recovery devices I'm familiar with basically break into whatever plumbing you already have for your drain lines and insert a copper to copper heat exchanger.

Jamie Lyons:
The material's sort of taken out of the equation, then.

Gary Klein:
That's correct. We're not wrapping pipe around an existing drain line. We're creating a section that's premade, intended to work a certain way. And so far all of those exchanges are copper to copper, that I'm aware of. By the way, I showed you a vertical one. There is a four-foot-long horizontal for shallow sloped drain lines that's become available from another company in Canada.

Jamie Lyons:
Great. That remark actually addresses another one of the questions. I'm going to shift over here to temperature settings for the hot water system. Gary already spoke -- spoke to this on your performance metrics slide. But one of our attendees cites a recent article that advocates that only set the hot water temperature only to the temperature needed for a shower without any additional regard for Legionnaires.' This is a practice, in your opinion?

Gary Klein:
So, if you set a storage water heater at the set point you'd like, and you have long showers, half of the event probably won't be very warm. Because the way storage tanks work, it just won't happen that way. You have a tankless water heater where you have got continuous flow through, then you can set the temperature down to what you need, but you need to set it to whatever temperature you need plus whatever it takes to get -- overcome the losses in the plumbing between the water heater and the use. So if the piping is very long and not very insulated and very large in diameter, you need to set the temperature somewhat higher. The question has to do with Legionella; it turns out that the 105-, the 110-degree temperatures that we like to take showers at are pretty close to what I would call to high fever temperatures, and pretty much all pathogenic bacteria just love them. I say it's probably the most beneficial bacteria -- why? It's warm body temperatures. They're comfortable there. If the water's flowing through, less of an issue than if it's not. But most of the recommendations that I've heard recently related to Legionella is for flow through devices like tankless, where you're not storing any significant amount of water if any, 125 to 130 and mix it down where you need it. And for storage tanks, 140 is still a good recommendation, even though we haven't been doing that in a while.

Jamie Lyons:
Very good. OK. Gary, we're just about up at the end here. So I'm going to grab back control of the slides here just for a second so we can show our attendees a list of resources they might be interested in. So hopefully we can see my slide now on my screen. Yes? Good. OK.

Jamie Lyons:
So again, thanks, everybody, and especially to you, Gary. Thanks for taking us through all this guidance. I understand my screen's being cut off again, so let me try to back out of this. There's too major resources we just want to highlight here. One is the program website, buildings.energy.gov. /challenge. And that links you to a number of different resources. There's an events tab, so you'll be able to see the schedule for upcoming webinars. You'll see the schedule for the in-person training that I mentioned. It will also highlight upcoming conference presentations. For instance, DOE Challenge Home has a track at the upcoming RESNET conference in about a month. We'll have 10 different sessions covering topics like this. There's also our partner locator tool, to locate builders and raters that are partners with the program. You can see the program specs, and as I mentioned, all these recordings from these webinars will be posted there in a library. So that's a good resource to be aware of and bookmark. And secondly, we note the Building America Solution Center. There's a website there. In case you can't see it, it's basc -- as in Building America Solution Center -- .pnnl.gov. And what this resource has done is taken an enormous amount of building performance research, mostly from the Building America program, but from some other sources as well, and stockpiled it into different layers so it's very easily navigated. And you can navigate by building system, you can navigate by a checklist for the DOE Challenge Home program or for the ENERGY STAR program. And quickly find a topic of interest and then see language on that, the recommended details and CAD format in some cases, several other layers of information. So it's designed to be a very user-friendly resource for the industry to get all the results and technical findings from Building America.

Jamie Lyons:
So with that, we're just up against our 1:15 deadline to wrap up, so again, everybody, thank-you very much for joining us. Look for more announcements on upcoming webinars. And thank-you, Gary and Lindsay, and have a great afternoon, everybody. Bye-bye.