In the late 2000s, the U.S. Department of Energy and a consortium of energy experts and HVAC representatives began work on increasing the HVAC furnace efficiency standards across the country, with higher minimum standards set for Northern states, including Oregon. Home heating in these states accounts for a large percentage of national natural gas and propane consumption.
The recommendations they made required the minimum AFUE (annual fuel utilization efficiency) of furnaces and boilers to increase from 78 to 90 percent, which would make a big difference in fuel consumption. A furnace with a 78 percent AFUE wastes 22 percent of the fuel it uses, while one that has an AFUE of 90 percent wastes just 10 percent. Over time, this hike in minimum AFUE would lower fuel consumption in the Northern states measurably.
However, problems arose when some HVAC industry interests became alarmed about the cost of retrofitting existing homes with furnaces with a 90 percent AFUE or higher system. Almost all of these systems are condensing furnaces that have a different footprint than standard furnaces. A condensing furnace requires two direct vents to the outdoors. One draws in fresh air for combustion, and the second vent exhausts the combustion gases, like a flue or chimney. They often vent out the side of the house rather than the roof.
These furnaces reach such high efficiency because they use the heat from the water vapor that burning gas creates; they do this by using a second heat exchanger over which the water vapor passes. As the exchanger collects the heat, the condensation drains into the plumbing supply, and the remaining waste gases go out the exhaust vent.
Some homeowners may have difficulty installing such a system without encountering great expense. While the increased HVAC furnace efficiency standards would be good for the environment, it puts a substantial financial burden on homeowners whose homes aren’t amenable to such systems. As a consequence, a lawsuit was filed and has been moving through the federal court system.
Although it’s unknown when the HVAC furnace efficiency standards will be implemented, there’s no doubt that these furnaces save energy. For more information, contact Roth Heating & Cooling. We’ve provided top-notch HVAC services for homeowners in the Portland area since 1976.