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Facts on Condensing Furnaces and How One Can Benefit You

piggy-bankIf you have a furnace in your house that’s more than 15 or even 20 years old, any replacement system will have a higher energy efficiency rating. This because standard for gas furnaces have changed dramatically over two decades, and even the new mid-efficiency models have a higher standard than the mid-efficiency models at the start of the 21st century.

If you upgrade to a new furnace at the end of this year’s heating season, you can expect energy-saving performance. And if you want a major efficiency upgrade, one of the best options is a condensing furnace. These furnaces score some of the highest AFUE ratings (efficiency ratings) of any heating system on the market, with as little waste as 2%.

How a Condensing Furnace Works

The name ­condensing furnace sounds a bit strange. What does “condensing” have to do with heating, and how does it help the furnace more efficiently use energy?

What “condensing” means is that the furnace runs its fuel through a process where it condenses the exhaust vapor from the first heating stage in order to draw more heat energy from it. In order to do this, the furnace needs to have a second heat exchanger.

The first heat exchanger is similar to the one in your current furnace: a metal chamber where hot combustion gas gathers and then raises the temperature of the metal exchanger walls so the air in the furnace will warm up. However, rather than allow the leftover combustion gas to escape out of a flue, the gas moves to the second heat exchanger. The vapor in the combustion can is condensed in the furnace to turn it back into a combination of water and carbon dioxide, a.k.a. carbonic acid. The process of condensing the gas causes the release of more heat to raise the temperature of the exchanger walls. The carbonic acid leaves the condenser through a PVC pipe and into a floor drain.

Essentially, a condensing furnace is “squeezing” the combustion gas for every drop of heat energy its got. That’s why these furnaces have such high energy efficiency.

How Efficient Are These Furnaces?

That’s the big question. A condensing furnace can have an AFUE rating as high as 98%. This means the furnace changes 98% of the natural gas it uses into heat energy, and only 2% goes to waste in the form of the carbonic acid sent down the drain. Compare this to a standard mid-efficiency furnace, which has an AFUE of around 85%. That’s a more than 10% efficiency increase—and that’s something you will notice on your heating bills over the winter.

We recommend all our customers who have natural gas furnaces look into the possibility of installing a condensing furnace. They cost more to install than mid-efficiency furnaces, but they can pay back their costs thanks to their energy-saving performance. However, they may not be right for your situation, so please call our experts for furnace service in Burlington, VT. We will ensure that you end up with the furnace that’s right for your house.

Red Rock Mechanical, LLC serves Northwest Vermont and Northeast New York. Request a free estimate for furnace installation or replacement.

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