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Understanding AFUE When “Furnace-Shopping”

When shopping for a furnace, one of the most important factors to consider is energy efficiency. The more energy-efficient your furnace is, the less money it will cost you to use it. That means you can keep warm and cozy all winter while keeping your heating costs nice and low.

But how do you know how energy-efficient a furnace is supposed to be? One way to tell is the AFUE. Have no idea what AFUE is? No worries: by the time you’re done reading this in the next few minutes, you’ll be an expert.

What Is AFUE, and What Does AFUE Stand For?

AFUE stands for Annual Fuel Utilization Efficiency. That’s an industry term for how well a furnace turns fuel (like gas) into heat you can use. A furnace’s AFUE is a percentage, like 80% or 90%.

Unfortunately, no furnace that uses natural gas, propane, or oil can turn 100% of that fuel into heat for your home. The furnace will use or waste some of that fuel during the heating process. The more of that fuel that can be turned into usable heat, the higher and better the furnace’s AFUE is.

For Example:

Suppose you’re thinking about buying a gas furnace with an AFUE that’s 80%. Let’s break down what that AFUE means.

The furnace uses natural gas to heat your home. As it’s burning the gas, it’s converting 80% of that gas into heat that it will use to warm your home. The other 20% of the gas it’s burning is not being used to warm your home.

So What Is a Good AFUE?

The Department of Energy (DOE) sets a minimum standard for AFUE that periodically changes. As of December 2021, the federal minimum is still 78%, so you can’t get a system installed in your home with an AFUE lower than that. However, there are preexisting systems still out there with an AFUE lower than 78%.

Here is how the DOE defines low-efficiency, mid-range-efficiency, and high-efficiency furnaces based on AFUE:

  • Low Efficiency (typically found in really old systems): 56% to 70% AFUE
  • Mid-Range Efficiency: 80% to 83% AFUE
  • High Efficiency (mots energy savings): 90% to 98.5% AFUE

If you want a furnace that will offer the most in terms of energy savings, you’ll want to consider an option with an AFUE that’s 90% or above. However, if you currently own an ancient furnace, you’ll notice substantial savings just by upgrading to a modern system, even if it doesn’t have the coveted Energy Star label.

Keeping AFUE In Mind When Furnace Shopping

There are going to be a lot of factors to consider when installing a furnace. The final choice regarding who will install the system is just as important as the equipment you pick. That being said, AFUE is a key factor you should keep in mind if energy savings are important to you. That percentage will help you differentiate between furnaces and understand which ones are more energy-efficient than their counterparts.

Furnace Replacement in Arlington, TX

At Tom's Mechanical, Inc., we know that a new furnace is a major investment, and we want to help you find the ideal choice for your home and your budget. Contact us today to schedule a quote with our reliable HVAC experts: (972) 388-3669.