AFUE Ratings Guide

If you’re considering an upgrade to your furnace, an important first step is to settle on an efficiency rating. This will impact your up-front costs and what you pay for home heating down the road. With this handy guide, you’ll understand more about AFUE ratings and how they affect you. 

What Is an AFUE Rating? 

AFUE is an acronym for Annual Fuel Utilization Efficiency. It is a standard for measuring how efficiently a furnace or boiler changes fuel into heat for your home over the course of a year. The higher the AFUE rating (on a scale of 0% to 100%), the more efficient the system is at converting fuel into usable heat. 

How Is AFUE Measured? 

AFUE ratings are estimated by calculating the ratio of the heat coming from your furnace to the amount of fuel it utilizes in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other variables that decrease efficiency. The result is displayed as a percentage, representing the amount of fuel converted into heat. 

Figuring out a heating system’s AFUE rating includes conducting a common test cycle to measure the heat output and fuel consumption. This test cycle is intended to simulate ordinary heating conditions in the course of the year, including both hot and cold periods. The heating system is then run at full capacity for an extensive period to determine its peak performance. 

What Is the Minimum AFUE Rating in 2023? 

The U.S. Department of Energy (DOE) has steadily increased HVAC efficiency ratings over the last few decades with hopes to increase energy efficiency and reduce emissions that harm the ozone/atmosphere. In 2023, the minimum rating for new gas furnaces was set to 81 AFUE. From 2015 to 2022, the South and Southwest regions had a minimum rating of 80 AFUE, and the North mandated furnaces to be rated 90 AFUE or higher. Better AFUE ratings lessen energy consumption, lowers utility bills and curbs the environmental impact of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When shopping for new furnaces, you may find many models around 80 and 90 AFUE, with little in between. This is because the technology needed to exceed 80 AFUE causes a substantial jump in performance. 

The 80 AFUE threshold has been the minimum criteria for gas furnaces in the U.S. since the 1990s. At this level, furnaces transform 80% of the fuel they consume into heat, with the remaining 20% forfeited to the atmosphere through the flue. 

Gas furnaces must incorporate more advanced technology to achieve higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These solutions help the furnace grab heat from the fuel source more effectively, increasing efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at approximately 98.5 AFUE. 

How Do AFUE Ratings Influence Furnace Costs? 

The total price of a furnace with a higher AFUE rating is usually higher than that of a lower AFUE-rated furnace. After all, more sophisticated technologies come at a higher price. The exact cost difference depends on the furnace make, size and efficiency rating. 

When evaluating the purchase price of a more efficient furnace, don’t forget the ongoing energy savings that awaits you. The real chance to save money on utility bills for the next ten years or longer will allow you to recoup the higher up-front investment. 

Does It Make Sense to Buy a Furnace with the Highest AFUE Rating Possible? 

While a higher AFUE rating results in more effective home heating and more affordable energy bills, we are not recommending that everyone should purchase a 95 AFUE furnace. Listed below are some factors to take into account when reviewing costs and efficiency ratings:  

• Climate: The colder the weather, the more frequently your high-efficiency furnace runs, and thus, provides an earlier ROI. Because of this, higher AFUE ratings are most appropriate in cold climates that take more heating than cooling to sustain a pleasant indoor temperature. 

• How long will you live there?: If you picture living in your home for some time, choosing a high-efficiency furnace may be a good investment given that it will pay for itself over time in energy savings. But, if you’re going to move within the next few years, the extra cost of a higher AFUE-rated furnace may not be worth it. 

• The cost of fuel: The benefit of an efficient furnace is more pronounced when the price of fuel is higher. You’ll see the savings in your bottom line as your furnace converts a higher percentage of fuel into usable heat for your home. 

Get a New Furnace Today 

For help determining the best furnace system for your needs and budget, rely on Service Experts Heating, Air Conditioning & Plumbing. We can help you figure out the initial costs and long-term benefits of different AFUE ratings to guide your decision. We are so certain that you’ll love working with Service Experts that we offer a 100% satisfaction guarantee! To find out more or to schedule a no-cost furnace installation estimate, please contact a Service Experts office near you

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