Purchasing Energy-Efficient Industrial Luminaires (High/Low Bay)

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Fluorescent luminaires have advantages over metal halide: longer life, higher lumen maintenance, shorter warm-up and restrike times, wider dimming range, better usage with occupancy sensors, better color rendering indices, and better color consistency.

Federal Energy Management Program (FEMP) provides acquisition guidance for industrial luminaires (high/low bay), a product category covered by FEMP efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law.

FEMP’s acquisition guidance and efficiency requirements apply to interior luminaires defined by NEMA LE-61 as either high bay linear, linear industrial (referred to as "low bay linear" in this product overview), high bay non-linear, or low bay non-linear. Recessed, surface mounted, and strip light fluorescent luminaires, suspended fluorescent luminaires, and exterior lighting are each covered by separate FEMP product overviews and efficiency requirements. Commercial downlight luminaires, residential luminaires, and some other commercial luminaire products are covered by ENERGY STAR specifications.

Industrial luminaires are used to light large, open interior spaces with high ceilings. In the Federal sector, these spaces include warehouses, commissaries, maintenance facilities, gymnasiums, and aircraft hangars. Depending on the mounting height of the luminaires used in these spaces, they are considered either high bay or low bay. The efficiency requirements in Table 1 apply to linear fluorescent and non-linear metal halide industrial luminaires.

This acquisition guidance was updated in July 2017.

Find Product Efficiency Requirements

Federal purchases must meet or exceed the minimum efficiency requirements in Table 1. These requirements are given in luminaire efficacy rating (LER), which is measured in lumens per watt (lm/W). A higher number indicates a more efficient product (i.e., more light output per unit of power input).

Table 1. Efficiency Requirements for Industrial Luminaires (High/Low Bay)
High Bay2, Linear, Fluorescent
Distribution Patterna Luminaire Size LER (lm/W)
T8 T5HO
Direct 1 foot x 4 foot ≥ 92 ≥ 78
2 foot x 4 foot   ≥ 81
Semi-Direct 2 foot x 4 foot   ≥ 70
Low Bay3, Linear, Fluorescent
Direct and Semi-Direct 1 foot x 4 foot ≥ 86  
2 foot x 4 foot ≥ 85  
1 foot x 8 foot ≥ 88  
High Bay, Non-Linear, Metal Halide
Distribution Pattern Input Watts (W) LER (lm/W)
Closed Open
Direct <150 ≥ 51 ≥54
150 - 399 ≥ 57 ≥ 67
400 - 999 65 ≥ 72
≥ 1000 ≥ 80 ≥ 81
Semi-Direct <150 ≥ 65 ≥ 68
150 - 399 ≥ 63 ≥ 80
400 - 999 ≥ 74 ≥ 81
≥ 1000 NA ≥ 94
Low Bay, Non-Linear, Metal Halide
Direct and Semi-Direct <150 ≥ 58 ≥ 60
150 - 399 ≥ 71 ≥ 67
400 - 999 ≥ 75 ≥ 74
≥ 1000 NA ≥ 81
a Suspended luminaires are designated into categories that differ by the percentage of light emitted in a direction above the horizontal plane of the luminaire. The categories used in this efficiency requirement include direct (0%-10% upward component) and semi-direct (10%-40% upward component).

Product performance for luminaires using fluorescent lamps must be determined in accordance with NEMA Standard LE 54, while those using high-intensity discharge lamps must be determined in accordance with NEMA LE 5B5.

Make a Cost-Effective Purchase by Buying a FEMP-Designated Product

FEMP calculated that the two different technologies for high and low bay industrial luminaire models below save money if priced no more than $108 above the less efficient model. The best available model saves up to $712. Federal purchasers can assume products that meet FEMP-designated efficiency requirements are life cycle cost-effective.

High Bay Direct 2 Foot by 4 Foot T5ho Fluorescent Luminaires

A high bay direct 2 foot by 4 foot T5HO fluorescent luminaire is cost-effective at the required efficiency level if priced no more than $13 above a less efficient model. Table 2 compares three types of product purchases and calculates the lifetime cost savings of purchasing efficient models.

Table 2. Lifetime Savings for Efficient High Bay Direct 2-Foot X 4 Foot T5HO Fluorescent Luminaires
Performance Best Available Required Model Less Efficient
LER (Lm/W) 92 81 73
Annual Energy Use (kWh) 783 889 986
Annual Energy Cost $70 $80 $89
Lifetime Energy Cost $870 $989 $1,097
Lifetime Cost Savings (per lamp) $227 $108 ======

 

View the Performance and Model Assumptions for Table 2

Performance Column

Input Power: Based on the wattage used by the luminaire with an output of 20,000 lumens.

Annual Energy Use: Assumes 3600 operating hours per year.

Annual Energy Cost: Calculated based on an assumed electricity price of $0.09/kWh, which is the average electricity price at federal facilities. (Source: Federal Government Energy/Water Use and Emissions in 2015 in Comprehensive Annual Energy Data and Sustainability Performance.)

Lifetime Energy Cost: Calculated as the sum of the discounted value of the annual energy cost and assumed product life of 15 years. Future electricity price trends and a 3% discount rate are based on federal guidelines (NISTIR 85-3273-31) and are from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, Energy Price Indices and Discount Factors for Life Cycle Cost Analysis. 2016

Lifetime Cost Savings: The difference between the lifetime energy cost of the less efficient model and the lifetime energy cost of the required model or best available model shown in kWh.

Best Available Model Column

Calculated based on the February 2017 update to DOE’s Compliance Certification Database. More efficient models may be introduced to the market after FEMP's acquisition guidance is posted. Due to differences in lumen output, the best available model should only be used in areas where a reduction in lumen output is acceptable.

Required Model Column

Calculated based on FEMP designated efficiency requirements. Federal agencies must purchase products that meet or exceed FEMP designated efficiency requirements.

Less Efficient Model Column

Calculated based on the minimum Federal standard for this product type.

Low Bay 150 To 399 Watt Enclosed Metal Halide Luminaire

A low bay 150 to 399 watt enclosed metal halide luminaire is cost-effective at the required efficiency level if priced no more than $246 above a less efficient model. The best available model saves even more money—$712 over 15 years. Table 3 compares three types of product purchases and calculates the lifetime cost savings of purchasing efficient models.

Table 3. Lifetime Savings for Efficient Low Bay 150 to 399 Watt Enclosed Metal Halide Lamp
Performance Best Available Required Model Less Efficient
LER (Lm/W) 98 71 62
Annual Energy Use 1,102 1,521 1742
Annual Energy Cost $99 $137 $157
Lifetime Energy Cost $1,226 $1,692 $1937
Lifetime Cost Savings (per lamp) $712 $246 ======

 

View the Performance and Model Assumptions for Table 3

Performance Column

Input Power: Based on the wattage used by the luminaire with an output of 30,000 lumens.

Annual Energy Use: Assumes 3600 operating hours per year.

Annual Energy Cost: Calculated based on an assumed electricity price of $0.09/kWh, which is the average electricity price at federal facilities. (Source: Federal Government Energy/Water Use and Emissions in 2015 in Comprehensive Annual Energy Data and Sustainability Performance.)

Lifetime Energy Cost: Calculated as the sum of the discounted value of the annual energy cost and assumed product life of 15 years. Future electricity price trends and a 3% discount rate are based on federal guidelines (NISTIR 85-3273-31) and are from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, Energy Price Indices and Discount Factors for Life Cycle Cost Analysis. 2016

Lifetime Cost Savings: The difference between the lifetime energy cost of the less efficient model and the lifetime energy cost of the required model or best available model (shown in kWh).

Best Available Model Column

Calculated based on the February 2017 update to DOE's Compliance Certification Database. More efficient models may be introduced to the market after FEMP's acquisition guidance is posted.

Required Model Column

Calculated based on FEMP-designated efficiency requirements. Federal agencies must purchase products that meet or exceed FEMP-designated efficiency requirements.

Less Efficient Model Column

Calculated based on the minimum Federal standard for this product type.

Determine When FEMP-Designated Products are Cost-Effective

An efficient product is cost-effective when the lifetime energy savings (from avoided energy costs over the life of the product, discounted to present value) exceed the additional up-front cost (if any) compared to a less efficient option. FEMP considers up-front costs and lifetime energy savings when setting required efficiency levels. Federal purchasers can assume FEMP-designated products are life cycle cost-effective. In high-use applications or when energy rates are above the federal average, purchasers may save more if they specify products that exceed federal efficiency requirements (e.g., the best available model).

Claim an Exception to Federal Purchasing Requirements

Products meeting FEMP-designated efficiency requirements may not be life cycle cost-effective in certain low-use applications or in locations with very low rates for electricity or natural gas. However, for most applications, purchasers will find that energy-efficient products have the lowest life cycle cost.

Operating conditions vary from facility to facility. To help determine cost effectiveness for operating hours different from the example, multiply savings by this ratio:

(Your Annual Hours of Use) ÷ (3,600 Annual Hours of Use)

Agencies may claim an exception to federal purchasing requirements through a written finding that no FEMP-designated product is available to meet functional requirements or that no such product is life cycle cost-effective for the specific application. Get additional information about federal product purchasing requirements.

Incorporate Federal Acquisition Regulation Language in Contracts

These mandatory requirements apply to all forms of procurement, including construction guide and project specifications; renovation, repair, energy service, and operation and maintenance contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Federal Acquisition Regulation (FAR) Part 23.206 requires agencies to insert the clause at FAR section 52.223-15 into contracts and solicitations that deliver, acquire, furnish, or specify energy-consuming products for use in federal government facilities. To comply with FAR requirements, FEMP recommends that agencies incorporate efficiency and energy performance requirements into both the technical specification and evaluation sections of solicitations.

Find Federal Supply Sources

The federal supply sources for energy-efficient products are the General Services Administration (GSA) and the Defense Logistics Agency (DLA). GSA sells products through its Multiple Awards Schedules program and online shopping network, GSA Advantage!. DLA offers products through the Defense Supply Center Philadelphia and online through FedMall (formerly DOD EMALL). Products sold through DLA are codified with 13-digit National Stock Numbers and, in some cases, a two-letter Environmental Attribute Code (ENAC). The ENAC identifies items that have positive environmental characteristics and meet standards set by an approved third party, such as FEMP.

The United Nations Standard Products and Services Code (UNSPSC) is a worldwide classification system for e‑commerce. It contains more than 50,000 commodities, including many used in the federal sector, each with a unique eight-digit, four-level identification code. Manufacturers and vendors are beginning to adopt the UNSPSC classification convention, and electronic procurement systems are beginning to include UNSPSC tracking in their software packages. UNSPSCs can help the federal acquisition community identify product categories covered by sustainable acquisition requirements, track purchases of products within those categories, and report on progress toward meeting sustainable acquisition goals. FEMP has developed a table of ENERGY STAR and FEMP-designated covered product categories and related UNSPSC codes.

Industrial Luminaire (High/Low Bay) Schedules and Product Codes

GSA offers fluorescent lamps through Schedule 56 (Buildings and Building Materials/Industrial Services and Supplies).

DLA offers industrial luminaire (high/low bay) models with the ENAC "HJ" at the end of the NSN.

The UNSPSC for high intensity discharge fixtures is 39111524 and for fluorescent high bay fixtures is 39111532.

Buyer Tips: Make Informed Product Purchases

Designing an Industrial Luminaire Installation: Special Considerations

Once the designer determines whether an application requires high bay or low bay luminaires, the next decision is whether to use a linear or a non-linear luminaire. The light source types for the luminaires covered by this product overview are fluorescent for linear luminaires and non-linear metal halide for non-linear luminaires.

Luminaires using fluorescent lamps and ballasts have the following advantages in comparison with those using metal halide: longer life, higher lumen maintenance, shorter warm-up and restrike times, more controllable in terms of wider dimming range and usage with occupancy sensors, better color rendering index, and better color consistency (less color shift over time). As a linear source, they also tend to have less glare than a metal halide luminaire using a point source, although T5HO luminaires may cause glare at lower mounting heights.

Luminaires using T5HO lamps can provide quality light output and higher fixture efficiency in high bay applications than luminaires using T8 lamps. A T5HO system is not as efficacious as a T8 system but produces more light output from the same number of lamps. Also, T5HO lamp operation is optimized at a higher ambient temperature than T8 lamps. This may be a factor in some locations. With more light produced from a smaller diameter lamp, T5HO lamps are much brighter than T8 lamps. This may produce glare in low bay applications, where luminaires using T8 lamps may be more appropriate. However, depending on the application, either lamp type may be used.

Metal halide systems may be the preferred option when it is desirable to have a point source rather than a linear light source. One main advantage of metal halide luminaires is lower maintenance costs, since these systems usually use one lamp in contrast to fluorescent luminaires using several lamps to provide sufficient light output. Other advantages include better operation in spaces with wide temperature range or low ambient temperature, availability of more closed luminaires for hazardous or corrosive environments, and availability of higher-wattage luminaires available for very high mounting heights.

When specifying metal halide luminaires, buyers are advised to select those using pulse start lamps and ballasts. (Note: The Energy Independence and Security Act of 2007, which took effect in 2009, requires that metal halide fixtures designed to be operated with metal halide lamps from 150 watts to 500 watts must contain ballasts that meet efficiency requirements that depend on ballast type (pulse start, magnetic probe start or non-pulse start electronic). Since most probe start ballasts do not comply with their higher efficiency requirements, this legislation is essentially driving the market toward pulse start metal halide luminaires.)

The advantages of pulse start over probe start operation include longer lamp life, higher efficacy, increased lumen maintenance, better color rendition, better starting at low temperatures, faster starting and warm-up times, shorter re-strike times, and better color shift control. In addition, buyers are advised to consider electronic metal halide ballasts, which provide higher efficacy, better lumen maintenance, and better control of color shift over the lamp life than do magnetic ballasts. For applications where high color rendition is desired, luminaires using ceramic metal halide lamps provide superior color rendering indices, as well as high lumen maintenance, especially when used with an electronic ballast.

Metal halide systems using pulse start electronic ballasts may have higher efficacy in terms of initial lumens than fluorescent systems. However, comparison of luminaires using these two different light sources should consider efficacy in terms of maintained or mean lumens. For new designs or substantial lighting renovations, by using higher-efficiency luminaires that provide sufficient lumen maintenance over the lifetime of the installation, designers may be able to use fewer luminaires per unit area, lower lamp wattage, or fewer lamps per luminaire to provide the desired light output. See the discussion in the third cost-effectiveness example above for more details.

High-pressure sodium (HPS) systems have been widely used in industrial and outdoor applications, but they do not meet the visual performance requirements of most interior high bay and low bay applications. The availability of pulse-start metal halide and high-efficiency fluorescent systems has substantially diminished the traditional advantages of long life and high efficacy that HPS systems have compared to standard metal halide or fluorescent systems. In circumstances where it is still desirable to use high-pressure sodium systems, they are required to meet the corresponding metal halide system requirements shown in Table 1.

Other high-intensity discharge lamp types such as mercury-vapor and low-pressure sodium have very poor color rendition. Mercury-vapor luminaires are much less efficient than those using metal halide or HPS light sources. (Note: The Energy Policy Act of 2005 eliminated the sale of mercury vapor ballasts as of January 2008. Mercury vapor lamps can be sold for use in existing luminaires, but no new luminaires using mercury vapor lamps can be sold because ballasts are not available for them.)

Once the major decisions on luminaire type, lamp type and ballast type have been made, the specifier should determine the light distribution needs of the application and make selections of light distribution, beam distribution and enclosure as appropriate. The choice of an open, closed, or lensed luminaire depends on the degree of protection required for the lamps, as well as glare control considerations.

Comparing Efficacy

Buyers are advised to compare LERs only within each luminaire category and subcategory, rather than choosing a luminaire for its LER value alone. Luminaire type, light source type, light distribution, enclosure type, luminaire size, lamp wattage, number of lamps, and ballast type may be selected for a variety of reasons based on the application—including color temperature, color rendition, light output, rated lifetime and cost.

LERs should be readily available in manufacturers' literature. If not, ask your supplier for LER values. If LER is not available, buyers may calculate LER using this formula:

LER = (Luminaire Efficiency x Total Rated Lamp Lumens x Ballast Factor) ÷ (Luminaire Watts Input)

LE, total rated lamp lumens, ballast factor, and luminaire watts input (input watts) may typically be found in manufacturers' product specification sheets and photometric reports.

Target efficacy rating (TER) is another informative metric for comparing luminaire effectiveness in delivering light to the application target. While LER uses luminaire efficiency (LE, the percentage of total lamp lumens that leaves the luminaire), TER uses energy effectiveness factor (EEF, the percentage of total lamp lumens that reaches the specified target area typical of the luminaire) in its calculation of luminaire efficacy. Since TER is available in some but not all manufacturer literature, this guidance relies on LER as its efficiency metric.

User Tips: Use Products More Efficiently

In addition to selecting the optimal luminaire for the application, building operators should endeavor to operate lighting only when needed. The use of lighting controls such as occupancy sensors, task tuning, and dimming when daylight is present (where applicable) should be considered to facilitate further energy savings. Controls are available for fluorescent systems and, to a more limited extent, for metal halide systems (due to their longer warm-up and restrike times). Industrial luminaires should be cleaned periodically to maintain their rated light output.

Lawrence Berkeley National Laboratory provided supporting analysis for this acquisition guidance.

 

Footnotes:

1 National Electrical Manufacturers Association Standard Publication LE 6-2009: Procedure for Determining Target Efficiency Ratings for Commercial, Industrial and Residential Luminaires.

2 "High Bay" refers to a luminaire used at a mounting height greater than 25 feet.

3 Suspended luminaires are designated into categories that differ by the percentage of light emitted in a direction above the horizontal plane of the luminaire. The categories used in this efficiency requirement include direct (0 – 10% upward component) and semi-direct (10 – 40% upward component).

4 National Electrical Manufacturers Association Standard Publication LE 5-2001: Procedure for Determining Luminaire Efficiency Ratings for Fluorescent Luminaires

5 National Electrical Manufacturers Association Standard Publication LE 5B-1998: Procedure for Determining Luminaire Efficiency Ratings for High-Intensity Discharge Industrial Luminaires