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The Federal Energy Management Program (FEMP) provides acquisition guidance for residential gas boilers, a product category covered by ENERGY STAR 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 for residential boilers and the associated ENERGY STAR efficiency requirements apply to natural gas boilers with an input rating of less than 300,000 Btu/h. Commercial boilers (i.e., those with an input rating of 300,000 Btu/h or greater) are excluded.

This acquisition guidance was updated in December 2018.

Find Product Efficiency Requirements

The U.S. Environmental Protection Agency (EPA) provides residential gas boiler efficiency levels and product specification information on its ENERGY STAR website. Manufacturers meeting these requirements are allowed to display the ENERGY STAR label on complying models. Federal buyers can use ENERGY STAR's list of certified residential gas boilers to identify or verify complying models.

Make a Cost-Effective Purchase: Save $1,389 or More by Buying ENERGY STAR

FEMP has calculated that the required ENERGY STAR-qualified residential gas boiler saves money if priced no more than $1,389 (in 2017 dollars) above the less efficient model. The best available model saves up to $2,265. Table 1 compares three types of product purchases and calculates the lifetime cost savings of purchasing efficient models for households with typical heating loads. Federal purchasers can assume products that meet ENERGY STAR efficiency requirements are life cycle cost-effective.

Table 1. Lifetime Cost Savings for Efficient Residential Gas Boiler Models
PerformanceBest AvailableENERGY STARLess Efficient
AFUE0.970.900.82
Annual Energy Use809 therm871 therm969 therm
Annual Energy Cost$570$614$683
Lifetime Energy Cost$11,465$12,342$13,730
Lifetime Cost Savings$2,265$1,389======
View the Performance and Model Assumptions for Table 1

Performance Column

Annual Fuel Utilization Efficiency (AFUE): A metric used to compare the energy conversion efficiency of residential boilers.

Annual Energy Use: Based on the test method referenced in 10 CFR 430, Subpart B, Appendix N and is presented in therms.

Annual Energy Cost: Calculated based on an assumed natural gas price of $0.74/therm, which is the average price at federal facilities.

Lifetime Energy Cost: Future natural gas price trends and a 3% discount rate are from the Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2018: Annual Supplement to NIST Handbook 135 and NBS Special Publication 709 (NISTIR 85-3273-33).

Lifetime Cost Savings: The difference between the lifetime energy cost of the less efficient model and the lifetime energy cost of the ENERGY STAR model or best available model.

Best Available Model Column

Based on the December 2018 ENERGY STAR-Qualified Products List; values shown are rounded to the nearest dollar. More efficient models may be introduced to the market after FEMP's acquisition guidance is posted.

ENERGY STAR Model Column

Based on December 2018 ENERGY STAR efficiency levels; values shown are rounded to the nearest dollar. Federal agencies must purchase products that meet or exceed ENERGY STAR efficiency levels.

Less Efficient Model Column

Based on products that meet the minimum federal energy efficiency standards.

Energy savings vary depending on individual household usage.

Determine When ENERGY STAR 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. ENERGY STAR considers up-front costs and lifetime energy savings when setting required efficiency levels. Federal purchasers can assume ENERGY STAR-qualified products and products that meet FEMP-designated efficiency requirements 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 ENERGY STAR or 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.

Agencies may claim an exception to federal purchasing requirements through a written finding that no FEMP-designated or ENERGY STAR-qualified product is available to meet functional requirements, or that no such product is life cycle cost-effective for the specific application. Learn more 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 (O&M) 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 requirements into technical specifications, the evaluation criteria of solicitations, and the evaluations of solicitation responses.

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 DOD EMALL. Products sold through DLA are codified with a 13-digit National Stock Number (NSN) 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 and ENERGY STAR.

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 numbers.

Residential Gas Boiler Schedules and Product Codes

GSA offers residential gas boilers through Schedule 51 V, Category 639 001 and Schedule 56, Category 563 27.

The DLA ENAC for residential boilers is "LN."

The UNSPSC for residential gas boilers is 40102004 and 40102005.

Buyer Tips: Make Informed Product Purchases

A boiler's efficiency is measured by annual fuel utilization efficiency (AFUE). The Federal Trade Commission requires new boilers to display their AFUE so consumers can compare heating efficiencies of various models. AFUE is a measure of how efficient the appliance is in converting the energy in its fuel to heat over the course of a typical year. Specifically, AFUE is the ratio of annual heat output of the boiler compared to the total annual fossil fuel energy consumed by a boiler. An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere. AFUE doesn't include the heat losses of the piping, which can be substantial.

An all-electric boiler has no flue loss through a chimney. The AFUE rating for an all-electric boiler is between 95% and 100%. The lower values are for units installed outdoors because they have greater jacket heat loss. However, despite their high efficiency, the higher cost of electricity in most parts of the country makes all-electric boilers an uneconomic choice. If you are interested in electric heating, consider installing a heat pump system.

Read about the standards for residential boilers.

You can identify and compare a system's efficiency by not only its AFUE but also by its equipment features.

Old, low-efficiency heating systems:

  • Natural draft that creates a flow of combustion gases
  • Continuous pilot light
  • Heavy heat exchanger
  • 56% to 70% AFUE.

Mid-efficiency heating systems:

  • Exhaust fan controls the flow of combustion air and combustion gases more precisely
  • Electronic ignition (no pilot light)
  • Compact size and lighter weight to reduce cycling losses
  • Small-diameter flue pipe
  • 80% to 86% AFUE.

High-efficiency heating systems:

  • Condensing flue gases in a heat exchanger for extra efficiency
  • Sealed combustion
  • 90% to 98.5% AFUE

Many states and electric utilities offer rebates or other incentives for the purchase of ENERGY STAR-qualified products. Use the ENERGY STAR Rebate Finder to see if your local utility offers these incentives. FEMP’s Energy Incentive Program helps federal agencies take advantage of these incentives by providing information about the funding-program opportunities available in each state.

User Tips: Use Products More Efficiently

Before buying a new boiler or modifying your existing unit, first make every effort to improve the energy efficiency of your home, then have a heating contractor size your boiler. Energy-efficiency improvements will save money on a new boiler because you can purchase a smaller unit. A properly sized boiler will operate most efficiently, and you'll want to choose a dependable unit and compare the warranties of each boiler you’re considering.

When shopping for high-efficiency boilers, look for the ENERGY STAR label. If you live in a cold climate, it usually makes sense to invest in the highest-efficiency system. In milder climates with lower annual heating costs, the extra investment required to go from 82% to 90% to 98% efficiency may be hard to justify.

Specify a sealed combustion boiler, which will bring outside air directly into the burner and exhaust flue gases (combustion products) directly to the outside, without the need for a draft hood or damper. Boilers that are not sealed-combustion units draw heated air into the unit for combustion and then send that air up the chimney, wasting the energy that was used to heat the air. Sealed-combustion units avoid that problem and also pose no risk of introducing dangerous combustion gases into your house. In boilers that are not sealed-combustion units, back-drafting of combustion gases can be a problem.

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