In the United States, gas furnace efficiency standards haven’t increased in nearly 30 years, despite multiple efforts to do so. Gas furnaces are currently required to have an annual fuel utilization efficiency (AFUE) level of 78 percent. AFUE measures units of heat output per 100 units of input, or put more simply, the amount of fuel that gets converted into heat for your home. The 78 percent AFUE level is the same level that was instituted on gas furnaces with the passage of National Appliance Conservation Act of 1987, which set national HVAC system efficiency standards.
In both 2007 and 2009, the U.S. Department of Energy proposed increasing the minimum AFUE level on gas furnaces. In 2007, the proposed increase was to a level of 80 percent, but that proposal was dropped in favor of levels that varie
d based on climate. The new proposal set a level of 90 percent for colder-climate states and 80 percent for warmer states.
That proposal also faced roadblocks, most notably in the fact that upgrading to a 90 percent AFUE furnace would require residents to switch from a non-condensing furnace to a condensing furnace. Condensing furnaces reuse some of the heat that would normally be pushed out of the home through vents. Switching from non-condensing to condensing usually requires modifications to venting and air intake. The proposed standards are currently in legal limbo, and probably will be delayed indefinitely as a result. So the old AFUE 78 percent minimum standard remains in effect for the whole country.
You can ensure high efficiency yourself by going with Energy Star-certified furnace systems. According to a recent survey, 35 percent of the furnaces sold in 2012 were Energy Star approved, which as of recently implemented changes, means they have at least a 90 percent AFUE in Southern states and 95 percent in Northern states, such as Minnesota.
At Marsh Heating & Air Conditioning, we’ve been keeping Minnesota homes warm since 1974. Contact us today to learn how you can make your HVAC system more efficient, or what choices you have with regard to efficiency when you want to upgrade your home’s furnace.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about efficiency standards and other HVAC topics, download our free Home Comfort Resource guide.
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