Condensing furnaces use special technologies to achieve extremely high levels of efficiency, measured by a metric known as “AFUE.” AFUE stands for “annual fuel utilization efficiency,” and it expresses how much of a given furnace’s energy input is converted into heat output. Most condensing furnaces have AFUE ratings of 90 percent or better, with the best-performing products converting as much as 98 percent of energy input into heat output.
Both conventional furnaces and their condensing counterparts use gas burners, which are powered by electrically controlled ignition components. However, condensing furnaces make great improvements in the process by which they extract heat from the energy input once combustion has been initiated. In conventional models, combustion takes place fairly quickly, which forces excess gases out of the system at a relatively rapid pace. Condensing furnaces, by contrast, slow down the combustion process. This allows them to extract greater amounts of thermal energy from the same amount of fuel input. They achieve this superior efficiency through the use of two heat exchangers: a primary heat exchanger, and a secondary exchanger.
The main heat exchanger in a condensing furnace runs the same way as the exchanger in a conventional furnace: it draws heat from the fuel input and circulates it through the system. However, the secondary heat exchanger continues to draw heat from the byproducts left behind by the initial heat exchange. In a conventional system, these byproducts are simply forced out of the system instead of being used for their heating potential.
As a homeowner, you should be aware that while condensing furnaces lead to improved energy efficiency, they also tend to require more careful upkeep and have additional components which must be properly cared for. One key example is the condensate drain line, which discharges the carbonic acid created by the operation of the secondary exchanger. This drain line must be carefully installed and connected to ensure proper operation.
To learn more about the benefits of high-efficiency furnaces, or to obtain a price quote, please contact us at Around the Clock Heating & Air Conditioning. We proudly serve homeowners throughout Los Angeles.
Our goal is to help educate our customers in Los Angeles, North Hollywood and surrounding areas 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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