What is an Annual Fuel Utilization Efficiency (AFUE) Rating?

by | Sep 14, 2023 | HVAC, Heating

When it comes to providing heat in your residence, the AFUE rating of your furnace plays an essential role. AFUE ratings measure the efficiency of a heating system. Higher ratings mean you use less energy and save more money. In the following article, we will discuss what an AFUE rating means and how it can save you money on your utilities. 

What is an AFUE rating? 

One of the most efficient ways to heat your home is to have a reliable and efficient furnace. The efficiency of a furnace is determined by its AFUE rating, which is a standard rating. 

So let’s jump right in and see what an official rating AFUE stands for. AFUE means fuel utilization efficiency. The rating is a measure of a furnace’s efficiency. It’s measured in percentage points, up to 100 percent. The rating shows the percentage of heat that is being used by the furnace compared to how much is being produced. 

So if we take the Trane XC95m as an example, we would see it has an AFUE rating of up to 97 percent. This is good. It means overall, 97 percent of the fuel it burns goes toward heating your home. As a result, only 3 percent will be wasted as part of the heating process.  

AFUE ratings were created by the American Society of Heating, Refrigerating, and Air Conditioning Engineers; it is a standardized rating now for all heating systems. That means an AFUE rating is mandatory by the U.S. Department of Energy. Every new furnace has to have one. 

Why Is an AFUE Rating Important?

The significance of a high AFUE rating cannot be understated. Higher ratings signify superior energy efficiency, resulting in reduced fuel waste and lower heating costs. Additionally, HVAC manufacturers and utility companies value these ratings; they often offer incentives like tax credits and rebates for efficient equipment. Even the government is offering incentives to go with more energy-efficient systems. Ask our home heating experts for details! 

What’s a Good AFUE Rating?

Next, we will discuss what a good AFUE rating is. The minimum standard AFUE for new furnaces is about 78% efficiency. That’s the low end. Most new furnaces usually have an AFUE rating between 80 and 85 percent. A high-efficiency unit has a rating between 90 and 98.5%. In any case, it’s important we mention that a good AFUE rating isn’t the only factor for determining the right furnace for your home. 

Several other factors should be taken into consideration. In addition to the AFUE rating of your furnace, you should consider the size of your home, the climate, the humidity, and the current heating and air conditioning system that’s installed in your home. 

How to Determine the AFUE Rating of Your Current System

The simplest way to determine your heating system’s AFUE rating would be to go to your furnace and look at the BTU input matched by the BTU output. This helps you determine what actual percentage your furnace is producing and how much heat it is using. 

What are the next steps? 

Last but not least, we can discuss what you can do next. Once you know what an AFUE rating is, we are always more than happy to discuss the complete list of comfort and efficiency ratings for each furnace we offer! As your local home comfort expert, we at Five Star Home Services are always here to help!  


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