Have you heard of sealed combustion furnaces? They’ve become a popular alternative to atmospheric furnaces. Both types of furnaces have a combustion chamber and heat exchanger. Only sealed combustion furnaces, however, pull in air from the outside. Atmospheric furnaces use the indoor air to absorb heat from the heat exchanger and, thus, warm the home. Below are five common myths about sealed combustion furnaces.
#1) Available in Electric Models
You won’t find sealed combustion furnaces available in electric models. Most of them use an electronic ignition to start up, but they all run on natural gas. They are known as “sealed combustion furnaces” because they use a sealed combustion process. They burn natural gas in a combustion chamber, and they pass hot combustion gases through a heat exchanger. The heat exchanger is sealed and not exposed to the surrounding indoor air.
#2) Doesn’t Dehumidify
Some homeowners assume that sealed combustion furnaces aren’t able to dehumidify the indoor air. If your home suffers from high humidity during the winter, though, you may want to use a sealed combustion furnace. It will both warm and dehumidify your home. A sealed combustion furnace will draw dry air from the outside, which it will use to absorb heat from the heat exchanger.
#3) Same as Condensing Furnaces
Sealed combustion furnaces aren’t necessarily the same as condensing furnaces. Condensing furnaces are characterized by the use of two heat exchangers. They pass the combustion gases through a second heat exchanger to squeeze out the maximum amount of heat. Most condensing furnaces are classified as sealed combustion gases, meaning they have two heat exchangers, but some of them only have a single heat exchanger.
#4) Less Efficient Than Atmospheric Furnaces
Sealed combustion furnaces are actually more efficient than atmospheric furnaces. Atmospheric furnaces rely on indoor air to absorb heat from the heat exchanger. An atmospheric furnace may draw warm indoor air away from living spaces to the heat exchanger, thus wasting energy. Sealed combustion furnaces don’t use indoor air. Instead, they use fresh air from the outdoors, resulting in greater efficiency.
#5) Not Safe to Use
You can rest assured knowing that sealed combustion furnaces are very safe to use. They are typically safer than atmospheric furnaces because they eliminate the possibility of backdraft. Backdraft is a phenomenon in which combustion gases enter a home’s living spaces rather than being expelled to the outdoors. Sealed combustion furnaces use a sealed combustion process with outdoor air, so they are protected from backdraft.