If you’re facing high energy bills in your Calgary-area home this winter, you’ve probably spent some time thinking about buying a high-efficiency furnace. However, you might be confused by all the new terminology and technology available in high-efficiency HVAC systems. Understanding how a high-efficiency furnace works can help you determine what features you need.
To qualify as a high-efficiency furnace, a heating system must have an AFUE (annual fuel utilization efficiency) of 90 or higher. That means that 10 percent or less of the fuel used to power the furnace is lost as exhaust gases. One type of high-efficiency furnace, called a condensing furnace, achieves this high AFUE by using a second heat exchanger.
A traditional furnace has one heat exchanger which pulls some heat from exhaust gases. However, a fair amount of heat is lost as the hot exhaust gases escape up the chimney. Even more heat is wasted when a traditional furnace uses air that you have paid to heat in order to create the combustion process.
In a high-efficiency system, a second heat exchanger uses a series of small tubes to process the exhaust gases, pulling even more heat from them than the first exchanger. The exhaust gases are converted to carbon dioxide and water. Put together, these two substances form carbonic acid. This slightly corrosive substance can eat through the furnace if not properly drained off using a PVC condensate drain pipe.
High-efficiency furnaces also tend to use sealed combustion where air is pulled from the outdoors to create combustion rather than using heated indoor air. In addition, they tend to have dual stage gas valves and blowers that can go full-blast when the furnace first comes on and the drop to a lower, more efficient speed when they’re just maintaining the home’s temperature.
So little heat is left to vent out once the second heat exchanger does its work.
For more information about buying a high-efficiency furnace or any other HVAC matters, contact Arpi’s Industries Ltd.We’ve proudly served Calgary, Alberta and the surrounding area for more than 49 years.
Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems). For more information about high-efficiency furnaces and other HVAC topics, download our free Home Comfort Resource guide.
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