Now that winter’s behind us in the Twin Cities area, it might not be a bad time to consider your furnace’s performance over the recent winter. You’ll have more time to mull over whether an upgrade makes sense from the standpoint of efficiency and performance. If you come to the conclusion that it does, consider a new high-efficiency condensing furnace. Given the length and severity of Minnesota winters, condensing furnaces deserve serious attention because they offer some of the highest energy efficiency available. These furnaces are similar to other kinds of forced-air heating systems, but they differ in their ability to extract nearly all the potential heat from the fuel.
The AFUE (annual fuel utilization efficiency) of a condensing furnace will run 90 percent or more, which means that at least 90 percent of the fuel it uses goes toward heating. The current minimum AFUE stands at 80, and a furnace with this rating wa
stes 20 percent of the fuel it uses. The main difference between a conventional furnace and a condensing system lies in the capture of the combustion gases and the heat that’s extracted from them.
Condensing furnaces have two heat exchangers. While the first one works like a normal furnace, the second one pulls the heat out of the gases that flow over it. When gas burns, it creates a lot of water vapor that carries substantial heat. As the heat leaves the vapor, it changes to a liquid, hence the use of the word “condensing” in the furnace name. The water vapor drains into a PVC pipe and then into your home’s drainage system.
Other differences exist in the engineering of these systems. Instead of using the ambient air in your home to burn the gas in the burner, this type of system pulls air into the sealed combustion chamber from the outdoors. It uses an air intake pipe that runs horizontally to the furnace. The flue also runs horizontally and the gases leaving it are much cooler than those leaving a conventional gas furnace.
The intake and exhaust vents have to be placed above the typical snow line for proper venting. Besides routine air filter changes and professional maintenance, homeowners need to make sure that the area around the vents is free from obstructions, including snow. These systems may also include upgraded components that increase their performance and lower heating bills.
If you would like to learn more about condensing furnaces, please contact us at Marsh Heating & Air Conditioning. We’ve provided reliable HVAC services in the Twin Cities area since 1974.
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 condensing furnaces and other HVAC topics, download our free Home Comfort Resource guide.
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