Up to $3,000 in Savings Available! Read More

Skip navigation

Start Your Career Today! Learn How


Kilowatt Heating, Air Conditioning and Electrical Blog

The Condensing Furnace: What You Need to Know


There is never a wrong time during the year to consider doing upgrades or heating repair in Studio City, CA or elsewhere in So Cal. Heaters do less work in our climate, and there are long stretches around the year where you can plan to make a major replacement without much worry about losing out on comfort because of lower temperatures.

With that in mind, we’d like to talk about one of the best choices available to you for an upgrade from your current, older furnace: the ­condensing furnace.

How a Condensing Furnace Works

Since you associate the word ­condensing with the air conditioner or with water, it sounds a bit strange when used for a furnace, which doesn’t use water at all. What condensing refers to in this case is condensing the vapor from the combustion gas after it has already gone through the standard process of heating the air. This pulls out more heat energy than a standard furnace.

It works like this: The gas jets of the furnace create the hot combustion gas that enters the heat exchanger of the furnace—the same as other gas furnaces. The combustion gas heats the exchanger, then air from the blower fan moves past it to warm up. At this point in a standard furnace, the leftover vapor in the exchanger would exit out a flue and move safely outdoors. In a condensing furnace, it instead moves to a second heat exchanger. Here, the vapor is condensed and turned into a liquid. Condensing releases heat, so the second heat exchanger can add more heat from the same energy source. The liquid then exits the second heat exchanger via a PVC pipe.

Why This Is Beneficial

The advantage of a condensing furnace is an increase in energy efficiency, or how well the furnace converts its fuel source (natural gas) into heating. The combustion process always creates some waste, such as the exhaust vapors the furnace sends out the flue. The condensing furnace boosts efficiency because it draws further heat energy from the natural gas in the second heat exchanger, leading to less waste.

What’s the efficiency difference? Not all models are the same, but all condensing furnace will score at least 90% AFUE, which means 90% of the fuel becomes heat energy. Many will score in the high 90s. Mid-efficiency furnaces are down in the 80s, and your old furnace may even have an AFUE in the 70s. Upgrading an old furnace with a condensing furnace can mean a more than 20% increase in efficiency, which you’ll see reflected in lower gas bills.  

Condensing furnaces cost more to install than single-heat exchanger furnaces, but they can often pay back their installation cost over a few years because of energy savings. However, you must have a professional assist you with installing any furnace, and that includes helping with selecting the model. A condensing furnace may not be ideal for your house or situation. You can trust that our technicians will be honest and helpful when it comes to furnace selection.

Kilowatt Heating, Air Conditioning and Electrical has served Los Angeles, Van Nuys and the San Fernando Valley since 1990. Schedule heating service with us today—or any day!

Comments are closed.