Residential boilers heat water and provide either hot water or steam to heat a home. Heat is generally distributed from the hot water or steam to the home using radiators.


The current standards for residential boilers took effect in 2021 and require gas-fired and oil-fired hot water boilers to meet minimum efficiency levels of 84% and 86%, respectively

In 2023, DOE proposed amended standards for gas-fired and oil-fired hot water boilers of 95% and 88%, respectively. If finalized, the proposed standards would effectively require all new gas-fired hot water boilers to use condensing technology. Condensing boilers extract additional heat by condensing the water vapor in the flue gases, resulting in efficiency levels of 90% or higher. 

*Annual fuel utilization efficiency (AFUE) is the energy efficiency metric for boilers and refers to the portion of energy in the fuel that is converted to useful heat. 


As of 2020, a little over nine million US homes were heated with boilers, around 65% of which are in the Northeast. Air-to-water and water-to-water heat pumps are efficient electric alternatives for hydronic heating. Air-to-water and water-to-water electric heat pumps meet the definitional criteria to be classified as consumer boilers and are commercially available in the US.; however, at this time, there are no federal efficiency standards for these products due to the absence of a federal test procedure. 

Savings through what year?: 2050
Energy saved (quads): 0.16
CO2 savings (million metric tons): 9.3
Net present value savings ($billion) 3% discount rate: $1.2
Net present value savings ($billion) 7% discount rate: $0.35


Federal Date States
Potential Effective Date of Updated Standard 2029
Updated DOE Standard Due 2024
Potential Effective Date of Updated Standard 2021
3rd Federal Standard Effective 2021
Updated DOE Standard Due 2016
Test Procedure - Last Revised - Standby/Off Mode 2016
3rd Federal Standard Adopted (DOE) 2016
2nd Federal Standard Effective 2012
Test Procedure - Last Revised - Standby/Off Mode 2010
2nd Federal Standard Adopted (Congress) 2007
2006 VT Standard Adopted
2005 MA Standard Adopted
2005 RI Standard Adopted
Test Procedure - Last Revised - Active Mode 1997
1st Federal Standard Effective 1992
1st Federal Standard Adopted (Congress) 1987
NAECA Initial Federal Legislation Enacted 1987

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.