cool jobs. hot future. apply today
we’re committed to keeping our customers & employees safe. learn more
talk to an expert today!

Subpage Sidebar

back to blog

Furnace Facts: Atmospheric vs. Sealed Furnaces


Because most homeowners don’t give much more thought to their heating system aside from “does this thing work when I need it to?” they often unaware of how the technology behind something like a standard natural gas furnace has advanced, and continues to advance. Of course, there’s no reason for homeowners to understand the cutting-edge technology of their heating systems, the same way that someone who works on a computer every day doesn’t need to understand the newest developments in microchips. But we’d like to share with you an important development in furnaces—the sealed furnace—and what makes it different from the more conventional atmospheric furnace. Knowing about this will help you understand how furnaces are becoming safer and more energy efficient.

What’s an “atmospheric” furnace?

We know, its sounds like something that supposed to be launched into the upper atmosphere. But an atmospheric furnace is simply a furnace that draws on air inside a home in order to mix with the natural gas from the burner and allow combustion to occur. A grill on the furnace pulls in this air for the combustion process. This, in turn, pulls air from the rest of the house. You could yank off the grill and see the flames of the burners working.

And what’s a “sealed” furnace?

It’s a furnace in which the combustion chamber is sealed off from the house interior. So where does it draw the air for combustion? Plastic tubes that run to the outside draw in fresh outdoor air for the process, usually next to the exhaust tube that releases the combustion fumes left over after the gas/air mixture is burned.

Why sealed is an improvement over atmospheric

Sealed furnaces are more energy-efficient in general because they lose less heat to the house as they work. By drawing air from the outside, they also aren’t removing already heated air from the house, and won’t create a vacuum indoors causing colder outside air to rush in. (This is the reason people often think of furnaces as drying out a house; they’re pulling in dry outdoor air). Finally, sealed furnaces are safer, reducing the danger of backdrafts and the escape of combustion vapors.

If you’re interested in a new furnace installation, or you need service for you current furnace, call on Raleigh Heating & Air, Inc. We service Clayton, NC.

Do NOT follow this link or you will be banned from the site!