Furnaces are the most common type of heating equipment in the United States. Furnaces burn natural gas, propane, or oil for heat and distribute the heat through a duct system. There are two main types of residential furnaces: weatherized (for outdoor installation, such as on rooftops) and non-weatherized. Non-weatherized furnaces are far more common and come in two forms: condensing and non-condensing. Furnaces with 90% or greater AFUE (annual fuel utilization efficiency) are known as "condensing" products because they condense water out of flue gases to recoup heat to warm the home that would otherwise be vented up the chimney.


The prior national standard for residential oil and gas furnaces was 78% AFUE. DOE raised the standard in 2007 to 80% AFUE, effective 2015. However, virtually all furnaces on the market have an AFUE of 80% or better, which prompted states and environmental and consumer groups to sue DOE over its 2007 decision. In April 2009, DOE accepted a “voluntary remand” in that litigation. In October 2009, manufacturers and efficiency advocates negotiated an agreement that, for the first time, included different standard levels in three climate regions: the North, South, and Southwest. DOE issued a direct final rule (DFR) in June 2011 reflecting the standard levels in the consensus agreement. The DFR became effective on October 25, 2011 establishing new standards: In the North, most furnaces will be required to have an AFUE of 90%.The 80% AFUE standard for the South and Southwest will remain unchanged at 80%. Oil furnaces will be required to have an AFUE of 83% in all three regions. The amended standards will become effective in May 2013 for non-weatherized furnaces and in January 2015 for weatherized furnaces. DOE estimates that the standards will save about 3.3 quads (quadrillion Btu) of energy over 30 years and yield a net present value of about $14 billion at a 3 percent discount rate.

Update: On January 14th, the U.S. Department of Energy (DOE) proposed to settle a lawsuit brought by the American Public Gas Association (APGA) that seeks to roll back gas furnace efficiency standards. As a result, the new standards, completed in 2011 and slated to take effect in May 2013, would be eliminated in favor of yet another round of DOE hearings and studies. Even if DOE completes a new rulemaking in two years, it's unlikely to take effect before 2020.


Space heating is the largest energy end-use in the U.S. residential sector, accounting for about 40% of total residential energy consumption. About 40% of U.S. households use natural gas furnaces (the most common equipment and fuel used for space heating), while a little more than 14% use electric furnaces and about 3% use oil furnaces. Non-weatherized, condensing furnaces are typically the most efficient (90% and above) as waste heat is not entirely dissipated outside (as with a weatherized furnace) and more heat is recovered from the combustion process from the latent heat created from the condensing of water vapor. No gas furnaces exist with AFUE ratings between 83–89% because problems arising from condensation occur within this range.



Fact Sheets



ASAP Press Releases



Federal Date State
Potential Effective Date of Updated Standard 2022
Updated DOE Standard Due 2017
2nd Federal Standard Effective ** 2015
3rd Federal Standard Effective 2013
3rd Federal Standard Adopted (DOE) 2011
2008 NH Standard Adopted
2007 MD Standard Adopted
2nd Federal Standard Adopted (DOE) 2007
2006 VT Standard Adopted
2005 MA Standard Adopted
2005 RI Standard Adopted
1st Federal Standard Effective 1992
1st Federal Standard Adopted (Congress) 1987
NAECA Initial Federal Legislation Enacted 1987

** Obsolete effective date. The effective date of the subsequent standard takes precedence.

States not showing an effective date have an ongoing rulemaking process to determine standards.

Timeline reflects state standards from 2001 to present; federal standards from inception to present.

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