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Atmospheric vs. Sealed Combustion Furnaces: What’s the Difference?

furnace-burners-burning-blueThe technology of heating and cooling a home is a field that’s always advancing. When it comes to furnaces, the new technology is designed to meet four goals:

  • Making the furnace safer
  • Increasing reliability and a reduction in repair issues
  • Better indoor comfort
  • Improving energy efficiency

Today we’re going to look at the sealed combustion furnace, which is an advance in furnace technology that hits all four of those goals. But first, we have to talk about atmospheric combustion furnaces, the older technology that sealed combustion furnaces aim to replace.

The Atmospheric Combustion Furnace

An atmospheric is the standard natural gas furnace of the past few decades. Essentially, if you can look inside your furnace and see the blue light of the flames on the burners when the system is running, you have an atmospheric combustion furnace. For combustion to take place, the burners must draw in air, and with this type of furnace the air simply enters the open combustion chamber directly. The furnace therefore is drawing on air from within the house to create combustion.

The Sealed Combustion Furnace

With the newer sealed combustion furnace, the combustion chamber is sealed off from the house. (You can’t look into the furnace and see the light of the burners.) Of course, the burners still need air, and the furnace draws this air through a PVC pipe that runs to the outside of the home. The furnace doesn’t draw on any air from inside the house to run.

So Why Is This Beneficial?

Let’s run down the four points above to see how sealed combustion improves a furnace all around:

  • Safety: Sealing off the burners from the house reduces the possibility of combustion danger outside of the furnace, and lowers the chance of the escape of natural gas into the home.
  • Reliability: A sealed combustion furnace is less likely to pull in debris that might cause the burners to become dirty and have trouble igniting.
  • Comfort: You may have heard that gas furnaces dry out the air in homes. What actually happens is that an atmospheric furnace draws away air from the inside of the home, creating a deficit of air indoors. Air from outside must rush in to make up the deficit—and this air is drier during the winter. It also increases the amount of drafts in a home. Sealed combustion takes away this problem because it draws air from outside.
  • Energy Efficiency: This is the big one, since sealed combustion furnaces have significantly helped improve efficiency ratings (AFUE) for gas furnaces. An atmospheric combustion chamber loses heat to the outside. A sealed combustion chamber, however, only draws in air through a small PVC pipe, meaning it loses almost no heat at all to the outside as it runs.

If you are interested in a new furnace installation in Haughton, LA or the surrounding areas, have a talk with one of our HVAC professionals. They’ll assist you with finding a furnace that meets your needs for comfort and your goals for saving energy. They’re also here to repair your current furnace if it has any problems during these last weeks of winter.

Call the Doctor of Home Comfort today: Hall’s Heating, Air Conditioning & Refrigeration.

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