AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, an important first step is to settle on an efficiency rating. That rating selection will impact your up-front costs and what you pay for home heating down the road. This guide is intended to inform you about AFUE ratings and how they affect you. 

What Is an AFUE Rating? 

AFUE stands for Annual Fuel Utilization Efficiency. It is an industry-standard measurement for how efficiently a furnace or boiler converts fuel into heat for your home within a 12-month period. 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 measured by calculating the ratio of the output of heat from the furnace or boiler to the amount of gas or diesel it utilizes in the process. This calculation factors in the energy lost through exhaust gases, radiation and other elements that reduce efficiency. The result is shown as a percentage, representing the amount of fuel converted into heat. 

Figuring out a furnace or boiler’s AFUE rating entails conducting a standard test cycle to quantify the heat output and fuel consumption. This test cycle is structured to simulate ordinary heating conditions throughout the year, including both hot and cold periods. The heating system operates at maximum capacity for an extended 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 past several decades in order to improve energy efficiency and reduce emissions that harm the ozone/atmosphere. In 2023, the minimum rating for new gas furnaces was recalculated to be 81 AFUE. From 2015 to 2022, the South and Southwest regions had a minimum rating of 80 AFUE, and the North called for furnaces to be rated 90 AFUE or greater. Better AFUE ratings cut down energy consumption, lowers power bills and reduces the environmental consequence of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When researching for new furnaces, you may discover many models around 80 and 90 AFUE, and not a whole lot else to consider. This is because the technology required to exceed 80 AFUE forces a significant leap in performance. 

The 80 AFUE threshold has been the minimum expectation 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% sacrificed to the atmosphere through the flue. 

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

How Do AFUE Ratings Determine Furnace Costs? 

The 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 cost. The exact cost difference is determined by the furnace make, size and efficiency rating. 

When considering the purchase price of a more efficient furnace, keep in mind the long-term energy savings that awaits you. The ability to save money on fuel bills for the next decade or longer will allow you to recoup the additional up-front investment. 

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

Though a higher AFUE rating leads to more efficient home heating and reduced energy bills, we are not recommending that every homeowner should pick a 95 AFUE furnace. Here are the factors to consider when comparing costs and efficiency ratings:  

• Climate: The colder the temperatures, the more frequently your high-efficiency furnace runs, and the sooner it will provide a return on investment. For that reason, higher AFUE ratings are most suitable in cold climates that require more heating than cooling to maintain a pleasant indoor temperature. 

• How long will you live there?: If you envision living in your home for quite a while, buying a high-efficiency furnace might be a smart investment because it will pay for itself over time in energy savings. However, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace may not be worth it. 

• Fuel costs: The benefit of an efficient furnace is more pronounced if your energy costs are high. You’ll experience noticeable savings once your furnace converts a higher percentage of fuel into usable heat for your home. 

Install a New Furnace Today 

For help determining the ideal heating system for your needs and budget, select Service Experts Heating, Air Conditioning & Plumbing. We can help you figure out the up-front costs and long-term benefits of different AFUE ratings to inform your decision. We’re so confident you’ll be satisfied with our services that we offer a 100% satisfaction guarantee! To find out more or to schedule a no-cost furnace installation estimate, please call a Service Experts office near you

Savings For You

See All Offers Here >

$50 OFF Any Repair

  • Save $50 on a Paid Service
  • Written 100% Satisfaction Guarantee
  • Plus, ask how to save an additional 15% and waive your trip charge!

Make No Payments for 30 Days!

  • Upgrade to Worry-Free Comfort with the Advantage Program and make NO payments for 30 days!

© 2023 Service Experts, Service Experts Heating & Air Conditioning, and the Service Experts logo and design are registered trademarks of Service Experts LLC and used under license by SE Canada Inc. All Rights Reserved. *Not applicable to the Advantage Program. See your signed Advantage Program Agreement for full details and exclusions. 100% Satisfaction Guarantee is subject to certain restrictions and limitations as set forth in the applicable Terms and Conditions.