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What’s a “Sealed Combustion” Furnace?

natural-gas-burnerFall is the time for you to arrange to have your home’s furnace inspected and tuned-up. But it’s also the time to consider whether you need to have a new furnace put in before the cold weather arrives. Our service technicians can help you make the choice when they come to your home for regular heating system maintenance.

If you do decide on new furnace installation in Fresno, CA, we recommend considering a sealed combustion furnace. This furnace type is an important development in heating technology that has allowed newer heating systems to score higher efficiency ratings than before. And high efficiency isn’t the only benefit.

The Sealed Combustion Basics

When we say a furnace is “sealed combustion,” it means it draws on air from outside the house to use for burning fuel (i.e. combusting fuel). The jets of the burners in a gas furnace must have air to mix with the gas, and in the standard “atmospheric furnace,” this air comes from within the house. The combustion chamber in the furnace is exposed to the space around it so the furnace can draw air directly inside.

A sealed combustion furnace, however, isn’t open to the house. It’s closed-off and draws air through a plastic PVC pipe that connects it to the outside. A second pipe attached to the combustion chamber sends out the exhaust. The combustion process is entirely isolated from the air in a house.

Why This Is Beneficial

You might already be picking up on some of the reasons a combustion gas furnace is advantageous. It sounds much safer to have the combustion process in the furnace sealed off from the house—and this is exactly right. Improved safety is an important benefit of sealed combustion. There is a lower likelihood of hazardous combustion byproducts getting into your house. Atmospheric furnaces aren’t inherently dangerous (provided they’re properly cared for), but a sealed combustion furnace adds an extra layer of safety.

Sealed combustion also makes a furnace more energy efficient. As we already mentioned, this is one of its biggest benefits. The combustion chamber loses less heat to the outside, making the furnace cost less to run. The highest efficiency furnaces today combine sealed combustion with a second condensing heat exchanger.

Finally, going with sealed combustion heating helps to solve a problem homes often encounter with gas furnaces: drier conditions. Furnaces don’t “dry out the air” in a home, as you may have heard. What actually happens is an atmospheric combustion chamber draws air from inside the house as it runs, causing an air deficit. Air from the outside—which is usually drier in the winter—then rushes in to replace it. Sealed combustion furnaces don’t remove air from indoors, and this can be a big help in keeping humidity balanced in winter.

Although any high efficiency furnace will cost more to install than a mid-efficiency unit, the payback with energy savings often makes it worthwhile. You can trust our professionals to help you balance out the factors in making a choice for a new furnace installation so you’ll end up with the best possible new heating system.

At Purl’s Sheet Metal & Air Conditioning, “Quality Is the Cornerstone of Our Success” Since 1952! Give us a call about heating system installation today.

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