Water Heaters


Residential water heaters are used to provide hot water for showering, dishwashing, clothes washing, and other household needs. Residential water heaters use diverse energy sources including electricity, natural gas, propane or fuel oil. There are two main types of residential water heater technology: storage and instantaneous water heaters.


DOE finalized the current standards for residential water heaters in April 2010, and they took effect in April 2015. The efficiency requirements vary depending on the type of water heater and the rated storage volume. For storage water heaters with a volume greater than 55 gallons, the standards require a heat pump efficiency level for electric products and condensing efficiency level for gas products. 

The residential water heater ENERGY STAR specification version 3.2 was released in 2017 and version 3.3 may be released in 2020. Version 3.3 includes "connectedness" criteria for qualified residential water heaters that will allow them to participate in utility demand response programs. In 2019, Washington adopted a design standard, requiring a communication port (CTA-2045 or equivalent) on electric storage water heaters. The port would enable utility programs to manage water heating loads. 


Residential water heating represents 18% percent of total annual household energy consumption in the U.S. About 48% of households have natural gas water heaters, while 45% have electric and slightly more than 6% burn propane or oil.

All storage water heaters waste energy keeping water hot even when no hot water is being used. Thicker tank insulation can decrease standby losses for all types of storage water heaters. Electric heat pump storage water heaters have demonstrated 50% savings in energy use compared to conventional electric storage water heaters and condensing gas water heaters can reduce energy consumption by about 25% compared to conventional gas storage units.


Savings through what year?: 2043
Energy saved (quads): 2.58
CO2 savings (million metric tons): 154
Net present value savings ($billion) 3% discount rate: 8.67
Net present value savings ($billion) 7% discount rate: 1.39

Fact Sheets


ASAP Press Releases



Federal Date States
Potential Effective Date of Updated Standard 2023
Updated DOE Standard Due 2018
3rd Federal Standard Effective 2015
Test Procedure - Last Revised - Standby/Off Mode 2012
Initial Federal Legislation Enacted 2012
3rd Federal Standard Adopted (DOE) 2010
2nd Federal Standard Effective 2004
2nd Federal Standard Adopted (DOE) 2001
Test Procedure - Last Revised - Active Mode 2001
1st Federal Standard Effective 1990
1st Federal Standard Adopted (Congress) 1987
NAECA Initial Federal Legislation Enacted 1987

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