The ABCs of Heating - Sealed Combustion Appliances

Appliances in the home that use natural gas for fuel, such as your furnace, water heater or clothes dryer, rely on combustion to generate heat. Traditionally, these appliances have utilized atmospheric combustion from air drawn inside the home, usually from the basement. The combustion exhaust gases are then expelled out of a flue or chimney. With sealed combustion appliances the supply and return air flow is tightly contained, so it does not have to rely on the air inside the home to convert fuel into heat.

The Advantages of Sealed Combustion

The main advantage of sealed combustion is efficiency. To achieve an Annual Fuel Utilization Efficiency (AFUE) of 90 or higher, furnaces use sealed combustion. With sealed combustion, the furnace connects to the outdoor air through a supply and a return pipe. Because the air supplied to the furnace is outdoor air, and the flue gases are exhausted back outside furnace efficiency is increased because it is not heating air only to send it outside. Another advantage of sealed combustion is safety. Without an exposed flame, there is no risk of flammable materials near the appliance catching fire. Burning natural gas can also generate dangerous carbon monoxide (CO) gas, which is more likely to enter the home through backdraft without a sealed combustion chamber. Have questions about sealed combustion? Give ABC Plumbing, Sewer, Heating, Cooling and Electric a call, we're here to help.