Same-Day Free In-Home Estimate & Systems as Low as $60/month! Read More

Skip navigation

Douglas Cooling & Heating Blog

AFUE Ratings & Furnace Installation: What to Know


If it’s time for a new furnace, you might be trying to figure out a lot of information at once. Should you get the same kind of furnace you had before? Are there better options available now? Might it be worth converting from gas to electric, or vice versa? Getting the answers to as many of your questions as possible will help you to make a choice you’ll be happy with in the long term.

We’d like to help you to gather the information you need. Some of the most important things to understand are AFUE (Annual Fuel Utilization Efficiency) ratings, and what to expect from furnace installation. Here are the facts. 


Annual Fuel Utilization Efficiency, or AFUE, is a measurement of how a furnace consumes energy. It is expressed as a percentage. So if you look at a furnace, and it is labeled as having an AFUE of 85%, what does that mean? This indicates how much of the energy used by the furnace is actually converted into heat. An AFUE of 85% means that 15% of the energy used is lost rather than becoming heat for your home.

Gas Furnace Efficiency

For your safety, a gas furnace must vent exhaust outside the home so you aren’t exposed to carbon monoxide. In most cases, this means the exhaust is released while it’s still pretty hot. This is how energy is lost rather than being entirely used to heat your home. But condensing gas furnaces allow the exhaust to cool before releasing it, so their AFUE can be as high as 98.5%.

Electric Furnace Efficiency

With no need to vent exhaust, an electric furnace’s efficiency is 100%. All the energy it consumes is converted directly into heat you can use. This means you won’t be wasting any energy with an electric furnace, but it doesn’t necessarily mean it’s cheaper to run. Natural gas is usually less costly than electricity.

Furnace Installation

Most furnace installations can be completed in a single day, sometimes in as little as four hours, but often taking six or more. The thing that can cause a furnace installation to take extra time is when modifications to your home are necessary. For example, if you’re connecting a gas furnace when you’ve only had electric before, or if damaged ductwork requires repairs, these things will require additional steps.

You can make your furnace installation go more smoothly by preparing your home a little bit before your appointment. First, make sure the path is clear—from the driveway, through the house—for the old furnace to be removed and the new one put in place. Second, clear space around the furnace for a spacious work area. Finally, shut your pets in another part of the house so they won’t get in the way.

If you have other questions about furnace options or furnace installation in Jefferson County, AL, we’d be delighted to help you get the answers you need.

“Your experience is what matters most!” Contact Douglas Cooling & Heating today for help with all your heating needs.

Comments are closed.