AFUE Ratings Guide

If you’re thinking about upgrading your furnace, an early choice in the process is to determine an efficiency rating. That first choice will influence 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 is an acronym for Annual Fuel Utilization Efficiency. It is a standard for measuring how efficiently a furnace or boiler switches fuel into heat for your home within 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 determined by calculating the ratio of the heat coming from your furnace to the amount of gas or diesel it utilizes in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other factors that diminish 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 involves conducting a standard test cycle to quantify the heat output and fuel consumption. This test cycle is intended to simulate typical heating conditions over the year, including both in-season and out-of-season periods. The heating system operates at peak capacity for a prolonged period to establish 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 several decades in order to increase energy efficiency and reduce greenhouse gas emissions. 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 lessen energy consumption, lowers utility bills and decreases 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, and not a whole lot else to consider. This is as a result of the technology necessary to exceed 80 AFUE creates a substantial jump 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% lost to the atmosphere through the flue. 

Gas furnaces must integrate more innovative technology to achieve higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and secondary heat exchangers. These technologies help the furnace extract heat from the fuel source more effectively, boosting efficiency from 80 to 90 AFUE or higher. Today’s best furnaces cap out at approximately 98.5 AFUE. 

How Do AFUE Ratings Affect Furnace Prices? 

The cost of a furnace with a higher AFUE rating is typically more than that of a lower AFUE-rated furnace. After all, more advanced technologies come at a cost. The exact cost difference will depend on the furnace manufacturer, size and efficiency rating. 

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

Is It Smart to Buy a Furnace with the Highest AFUE Rating Possible? 

Although a higher AFUE rating translates into more effective home heating and reduced energy bills, this doesn’t necessarily mean all homeowners should choose a 95 AFUE furnace. Listed below are some factors to take into account when evaluating costs and efficiency ratings:  

• Seasonal weather conditions: The colder the temperatures, the more your high-efficiency furnace operates, and thus, provides an earlier ROI. Because of this, higher AFUE ratings are most appropriate in cold climates that demand more heating than cooling to maintain a comfortable indoor temperature. 

• When do you plan to move?: If you picture living in your home for some time, purchasing a high-efficiency furnace may be a good investment because it will pay for itself over the coming years in energy savings. However, if relocating is in your plans within the next couple of years, the extra cost of a higher AFUE-rated furnace would not be recommended. 

• Energy prices: The benefit of an efficient furnace is more pronounced when the price of fuel is higher. You’ll realize the savings each month once your furnace converts a higher percentage of fuel into usable heat for your home. 

Install a New Furnace Today 

When trying to find the ideal furnace system for your needs and budget, choose Service Experts Heating, Air Conditioning & Plumbing. We can help you sort out the up-front costs and long-term benefits of different AFUE ratings to steer your decision. We know you’ll love working with Service Experts so much so that we offer a 100% satisfaction guarantee! To find out 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 >
Service Experts Advantage Program logo

Make No Payments for 30 Days!

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