Commercial Warm Air Furnaces

The Product:

Commercial warm air furnaces are defined as units with capacities of at least 225,000 Btu/hr (British Thermal Units per Hour). They are designed to supply heated air through a duct system. In practice, commercial furnaces are gas or propane heating sections of packaged roof-top units (RTUs) used for small- to mid-sized commercial buildings. RTUs are essentially air conditioners that may also contain a heating section.

The Standard:

Congress established the first national standards for commercial warm air furnaces as part of the Energy Policy Act of 1992. The standards took effect in 1994 and specify minimum thermal efficiency levels of 80% for gas-fired equipment and 81% for oil-fired equipment.

In April 2015, DOE formed a working group to negotiate new energy conservation standards for commercial warm air furnaces. The working group recommendations, which raise the efficiency levels to 81% and 82% for gas-fired and oil-fired equipment, respectively, were ultimately adopted by DOE in a December 2015 direct final rule. The new standards will take effect on January 1, 2023.

Key Facts:

Much greater energy savings from commercial warm air furnaces are possible using condensing technology. Condensing furnaces extract additional heat by condensing the water vapor in the flue gases and reach efficiency levels of 90% or higher. 

Savings through what year?: 2053
Energy saved (quads): 0.23
CO2 savings (million metric tons): 12
Net present value savings ($billion) 3% discount rate: $1.0
Net present value savings ($billion) 7% discount rate: $0.3


Federal Date States
Potential Effective Date of Updated Standard 2029
Updated DOE Standard Due 2024
3rd Federal Standard Effective 2023
Potential Effective Date of Updated Standard 2019
3rd Federal Standard Adopted (DOE) 2016
Updated DOE Standard Due 2016
2nd Federal Standard Effective 2003
2nd Federal Standard Adopted (DOE) 2001
1st Federal Standard Effective 1994
EPACT Initial Federal Legislation Enacted 1992
1st Federal Standard Adopted (Congress) 1992

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