What Are Sealed Combustion Appliances?

It may come as no surprise that appliances relying on combustion, such as your furnace or hot water heater, can pose some safety risks. Sealed combustion appliances reduce the risk by changing the source of the air supply. As a result, appliances with sealed combustion are safer, but also more efficient.

What is Atmospheric Combustion?

In order to understand what sealed combustion appliances do, you need to know how appliances without sealed combustion function normally. Many older furnaces rely on what is called “atmospheric combustion.” With atmospheric combustion, the air is drawn into the furnace from inside the home, often from the basement. That air is then expelled out of a flue or chimney with fuel exhaust. This process is less efficient because the air in the home, which has already been heated, is then pulled back into the furnace and sent outside with the flue gases. In essence, the process heats some air to be sent outside, instead of using cold air to burn the fuel.

How is Sealed Combustion Different?

Sealed combustion appliances are both safer and more efficient in energy consumption and fuel usage. In fact, if you purchase a furnace with an Annual Fuel Utilization Efficiency (AFUE) of 90 or higher, it will be a sealed combustion furnace. With sealed combustion, the furnace has supply pipes as well as a return pipe, both of which connect to the outdoor air. As such, the air supplied to the furnace is outdoor air, and the flue gases are exhausted back outside. This increases the furnace efficiency, because it is not heating air only to send it outside. Sealed combustion furnaces are also safer, because there is less risk of sending air with combustion gases throughout the home due to backdraft.

Which Appliances Can Be Sealed Combustion?

Although you may think mostly about your furnace during the winter, there are other appliances that also can use a sealed combustion arrangement. For example, high efficiency boilers are sealed combustion appliances. Your hot water heater probably uses the same fuel source as your furnace, and has just as much need for air supply and combustion exhaust. With a sealed combustion furnace and hot water heater, you may dramatically improve your overall heating efficiency and decrease your home’s risk of fire or explosion.

There are many reasons you might consider purchasing an appliance with sealed combustion, such as a furnace or hot water heater. Sealed combustion means that the air supply and return are tightly contained, and not reliant upon the air inside the home to convert fuel into heat. The end result is that sealed combustion appliances offer greater fuel efficiency, and a lower likelihood of spontaneous combustion or the ill effects of poisonous gases spreading through the home. For more information about sealed combustion appliances for your home, contact the Sacramento HVAC experts at Ace Plumbing.