AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, an early choice in the process is to decide on an efficiency rating. That rating selection will influence 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 stands for Annual Fuel Utilization Efficiency. It is an industry-standard measurement for how efficiently a furnace or boiler switches 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 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 expressed as a percentage, representing the share of fuel converted into heat. 

Figuring out a heating system’s AFUE rating includes conducting a standard test cycle to measure the heat output and fuel consumption. This test cycle is designed to simulate ordinary heating conditions throughout the year, including both on and off periods. The heating system operates at maximum capacity for an extensive period to establish its peak performance. 

What Is the Minimum AFUE Rating in 2023? 

The U.S. Department of Energy (DOE) has gradually increased HVAC efficiency ratings over the last few 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 required furnaces to be rated 90 AFUE or greater. Better AFUE ratings reduce energy consumption, lowers energy 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 find many models around 80 and 90 AFUE, but not much in between. This is because the technology necessary to exceed 80 AFUE forces a significant rise in performance. 

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

Gas furnaces must integrate more innovative technology to attain higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and supplementary heat exchangers. These techniques help the furnace extract heat from the fuel supply more effectively, improving efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at approximately 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. Not surprisingly, more sophisticated technologies come at a higher price. The exact cost difference depends on the furnace brand, size and efficiency rating. 

When evaluating the up-front cost of a more efficient furnace, keep in mind the ongoing energy savings that awaits you. The real chance to save money on energy bills for the next ten years or longer helps you to recoup the extra up-front investment. 

Should You Buy a Furnace with the Highest AFUE Rating Possible? 

While a higher AFUE rating leads to more efficient home heating and more affordable energy bills, this doesn’t necessarily mean every homeowner should pick a 95 AFUE furnace. Below are a few factors to consider when reviewing costs and efficiency ratings:  

• Climate: The colder the climate, the more frequently your high-efficiency furnace runs, and thus, provides an earlier ROI. For that reason, higher AFUE ratings are most suitable in cold climates that require more heating than cooling to sustain a comfortable indoor temperature. 

• When do you plan to move?: If you imagine living in your home for some time, purchasing a high-efficiency furnace may be a wise investment because it will pay for itself over the next few years in energy savings. However, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace would not be recommended. 

• Fuel costs: The impact of an efficient furnace is more evident when the price of fuel is higher. You’ll see the savings in your bottom line once your furnace converts a higher percentage of fuel into usable heat for your home. 

Consider a New Furnace Today 

When trying to find the perfect heating system for your needs and budget, turn to Service Experts Heating, Air Conditioning & Plumbing. We can help you sort out the initial costs and long-term benefits of different AFUE ratings to guide your decision. We’re so confident you’ll be satisfied with our services that we offer a 100% satisfaction guarantee! To learn more or to schedule a no-cost furnace installation estimate, please get in touch with a Service Experts office near you

Savings For You

See All Offers Here >
parts and labor icon

$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!
maintenance icon

$50 OFF HVAC Tune-up Special

There’s no reason to skip your seasonal maintenance that saves energy and helps ensure your air conditioner and heater will work reliably all season long.

  • Regularly $129, now only $79
  • Save up to 30% on energy bills
  • Written Expert Service Guarantee

© 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.