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Does a Furnace Dry Out the Air in a House?

gas-jetsThe gas furnace is such a common type of home heating system that there are few objections to having one installed. Yes, people sometimes have concerns about using natural gas in a house, but if a furnace receives annual professional maintenance and proper care, it rarely poses any safety hazards.

But there is one negative often raised about the gas furnace, which is that it dries out the air in a house. Because dry air makes the inside of a house feel colder than it is and can also lead to health problems, this isn’t a situation anyone wants. But is there any truth to this?

The Effect of the Standard Furnace on Indoor Humidity

The answer is that running a gas furnace can lead to lower humidity inside a house. The furnace’s burners don’t dry out the air, however. What happens is a bit more complicated.

The standard older furnace is what’s known as an atmosphere furnace. This means the furnace’s combustion chamber is open to the air outside of the unit. If you can look into your furnace and see the light from the burners when they’re on, you have an atmosphere furnace.

This type of furnace draws air from the house into the combustion chamber. The jets must have air to be able to light and continue to burn, and it pulls this air directly into the chamber from outside the furnace. This causes an air deficit inside the house; the air outdoors comes inside to make up that deficit. Because the outside air in winter is usually drier than the inside air, this leads to a humidity drop.

The Sealed Combustion Furnace

The atmosphere furnace is being replaced with a newer furnace type, which uses sealed combustion. A sealed combustion furnace doesn’t expose the burners to the air around the furnace, but instead has a chamber that’s completely sealed against the rest of the house.

Where does the furnace draw the air it needs for combustion? It comes from the air outside the home: a PVC pipe leads from the combustion chamber to the outdoors. The furnace won’t create any air deficit leading to a rush of colder outside air into the house.

In addition to preventing drier conditions, the combustion furnace has several other benefits. It’s safer, since the combustion chamber isn’t exposed to the indoors. It’s also more energy efficient, as no heat is lost during the combustion process to the outside. If you are planning to a have a new gas furnace installed this fall or winter, we recommend looking into a high-efficiency unit with sealed combustion.

Furnace Installation Experts Are Ready to Help

If you are looking for a new furnace in Wayne, NJ, you can count on our HVAC professionals to select the best new unit to meet your needs. We are also experts in indoor air quality, so we’ll make sure you don’t end up with dried out air. If you still have trouble with low humidity after a new furnace is put in, ask us about a whole-house humidifier.

Need help with your home’s furnace? Advanced Mechanical Services offers heating assistance throughout the Tri-State Area.

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