Electric vs. Gas: What Furnace Is More Efficient?

Monday, February 15th, 2021

natural-gas-furnaceIf you’re looking for a new heater installation this time of the year, chances are that you’re in a bit of a rush. We really want to encourage you to slow down and take some time with this decision. Rushing into a furnace purchase can leave you with a system that’s not properly matched for your specific home and needs, and therefore doesn’t work as efficiently as you need it to.

About efficiency—efficiency is the rating of the heating output of your furnace compared to the amount of energy that it consumes. However, this doesn’t necessarily mean that a furnace with a higher efficiency rating will, by default, cost less to run. A good example of this is when you’re looking at the AFUE ratings of electric furnaces versus that of gas furnaces.

Annual Fuel Utilization Efficiency

Here’s a look at how exactly furnaces are rated for efficiency—when you look at a furnace’s statistics, first you’ll see an AFUE rating—annual fuel utilization efficiency. It is the measurement of energy efficiency in a gas-powered heating system and is listed as a percentage. This percentage reflects the amount of the energy source that the furnace converts directly into the heat energy it sends into the home. The remaining energy goes to waste as exhaust.

For instance, a mid-range gas furnace with an AFUE rating of 80% converts 80% of its natural gas into heat and loses 20% as an exhaust that exits via a flue.

Standard Efficiency Ratings Explained

The efficiency ratings for natural gas furnaces have increased over the years. For a long time, the typical high-efficiency furnace had an AFUE of about 70%. If your furnace is about a decade old or more, then it likely has an AFUE rating a bit higher than that—about 80-85%. Modern high-efficiency gas furnaces, though, usually score in the 90s, and there are even condensing furnaces with AFUE ratings of 98%.

With an electric furnace, the efficiency range is much simpler. No energy is wasted whatsoever because there is no natural gas to burn, so all-electric furnaces have an AFUE of 100%.

“Oh! So I Should Get an Electric Furnace!”

Here’s the thing—when it comes to furnaces, higher efficiency doesn’t necessarily mean lower costs. Overall as a fuel, natural gas is lower cost than electricity. Therefore you could select a gas furnace with a 90-98% AFUE rating and it could cost you less to run than the 100% AFUE rating electric furnace.

So what’s best for your home? Well, it depends. If you’ve always had a gas furnace, and its AFUE rating is on the lower side, then upgrading to a modern gas furnace is going to benefit you no matter what, when it comes to monthly costs. If you’ve always been using an electric furnace though, and have access to a city gas line, you may want to look into a modern gas furnace!

Our professionals can help you make an educated decision, and we look forward to helping.

For quality Joliet, IL HVAC installation and more, contact Comfort First Heating and Cooling, Inc.—where we put your comfort first!

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