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.


Congress established standards for residential boilers as part of the Energy Independence and Security Act (EISA) of 2007, and they took effect in 2012. The standards for each type of boiler include a requirement for annual fuel utilization efficiency (AFUE) and/or design requirements. AFUE refers to the portion of energy in the fuel that is converted to useful heat. The initial standards for residential hot water boilers required a minimum efficiency of 82% for gas-fired equipment and 84% for oil-fired equipment.

In 2016, DOE finalized new standards for residential boilers that raised the minimum efficiency levels to 84% and 86% for gas-fired and oil-fired hot water boilers, respectively. The new standards took effect in 2021.


About nine million US homes are heated with boilers, 60% of which are in the Northeast. The efficiency of residential boilers can be improved by increasing the size of the heat exchanger. However, significantly greater savings can be achieved using condensing technology. Condensing boilers extract additional heat by condensing the water vapor in the flue gases, resulting in efficiency levels of 90% or higher.

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.