The Days of Non-Condensing Gas Furnaces are Limited

Gita Subramony for Zondits, March 19, 2015

The DOE has proposed new rules regarding gas furnaces and minimum efficiencies. The new rules will raise the minimum efficiency for gas furnaces to 92 AFUE. The previous standard, which went into effect in 1992, required only 78 AFUE.

After facing challenges from the natural gas industry, the DOE has now proposed the first update to this standard since the early 1990s. The US Energy Information Agency performed an analysis of commercially available gas furnaces and concluded that the new standards (if put into effect as they currently are) will likely eliminate non-condensing gas furnaces from the market since their efficiency levels will not meet the requirements. Although condensing gas furnaces are more efficient, installing them might present additional switching costs for the residential sector.


Proposed efficiency standard may eliminate noncondensing gas furnaces

EIA, February 17, 2015

Following a court challenge that caused a previous proposal to be sent back for further analysis, the U.S. Department of Energy (DOE) has issued a new proposed rulemaking to increase the minimum efficiency standards for gas furnaces, which are mostly fueled by natural gas but also include propane furnaces. Gas furnaces are one of the largest energy consumers in the residential sector, accounting for about one-fifth of the energy delivered to homes and apartments in the United States. The proposed standard would increase the minimum efficiency standard for these furnaces for the first time since 1992.

gas furnace

As discussed in a previous Today in Energy article, gas furnaces were one of the first products covered by federal appliance standards. The first standard, enacted by Congress in 1987 and made effective starting in 1992, established the minimum efficiency level of furnaces at 78 annual fuel utilization efficiency (AFUE), meaning 78 units of heat output for every 100 units of energy input.

Several earlier proposals to increase the minimum efficiency of furnaces met with opposition—first, for not being stringent enough, and later, for being too stringent. The most recent of these previous proposals would have established a regional standard of 90 AFUE in colder climates and 80 AFUE in warmer climates. Similar regional standards for other equipment such as heat pumps and air conditioners recently took effect, but the furnace rule was challenged by natural gas utilities. In April 2014, the U.S. Court of Appeals voided the standard and insisted that DOE reevaluate the rule.

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