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Sealed Combustion vs. Atmospheric Combustion in Gas Furnaces

The technology of heating and cooling is never static. New developments are constantly finding better and less expensive ways to provide comfort for homes and commercial buildings. For example, even though gas furnaces have been around for decades, they remain a competitive type of heating system because new advances in design have made them safer and more energy efficient.

We’ll look at one advance in gas furnace manufacture, the sealed combustion chamber, that has created improvements in almost all areas: comfort, efficient, safety.

The Sealed Combustion Furnace

The combustion chamber is the part of the furnace where natural gas is burnt to create the heat that enters into the heat exchanger. For combustion to occur, the furnace needs to draw in air to mingle with the gas from the burners. Where the furnace draws this air is the difference between standard atmospheric combustion and sealed combustion.

An atmospheric combustion chamber, found on most older furnaces, is open to the rest of the house. The chamber draws air into it through a grill on the furnace, removing it from the atmosphere inside the house. After combustion, the exhaust vapors are sent out a flue. But a sealed combustion chamber is closed off from the house, and draws its air from outside the house through a plastic pipe.

Why does this make a difference in performance, comfort, and safety?

  • Performance: A sealed combustion chamber doesn’t lose any heat to the outside of the furnace, making it more energy efficient.
  • Comfort: When a furnace draws air from inside house, the air must be replaced. And where does this new air come from? The outside of the house. This leads to an influx of cool air, which not only alters the temperature but also makes the air drier. (This is the reason that furnaces are often said to “dry out the air” in a building.) A sealed combustion chamber doesn’t create this vacuum.
  • Safety: A sealed combustion chamber reduces the chance of toxic combustion byproducts, such as carbon monoxide, entering the home.

If you are looking for new furnace installation or replacement in Winnetka, IL, call on the Malek Heating & Cooling—your Chicagoland experts since 1998!

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