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 as time goes on. Use this guide to learn more about AFUE ratings and how they affect you.
What Is an AFUE Rating?
AFUE stands 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 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 a furnace's heat output to the amount of fuel it utilizes in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other elements that decrease efficiency. The result is shown as a percentage, representing the share of fuel converted into heat.
Figuring out a heating system's AFUE rating entails conducting a conventional 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 on and off periods. The heating system is then run at full capacity for a prolonged period to define its peak performance.
What Is the Minimum AFUE Rating in 2023?
The U.S. Department of Energy (DOE) has slowly increased HVAC efficiency ratings over the last few decades in an effort to encourage 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 better. Better AFUE ratings reduce energy consumption, lowers utility bills and decreases the environmental impact of heating your home.
Why Do Gas Furnaces Jump from 80 to 90 AFUE?
When researching for new furnaces, you may notice many models around 80 and 90 AFUE, with little in between. This is because the technology required to exceed 80 AFUE causes a considerable jump 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 convert 80% of the fuel they consume into heat, with the remaining 20% forfeited to the atmosphere through the flue.
Gas furnaces must use more advanced technology to secure 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 source more effectively, raising 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 Prices?
The total price of a furnace with a higher AFUE rating is typically more than that of a lower AFUE-rated furnace. Basically, more advanced technologies come with a higher price tag. The exact cost difference is determined by the furnace manufacturer, size and efficiency rating.
When considering the initial cost of a more efficient furnace, keep in mind the long-term energy savings that awaits you. The real chance to save money on utility bills for the next ten years or longer will definitely allow you to recoup the additional up-front investment.
Should You Buy a Furnace with the Highest AFUE Rating Possible?
Though a higher AFUE rating leads to more effective home heating and lower energy bills, we are not saying all homeowners should purchase a 95 AFUE furnace. Here are the factors to think about when evaluating costs and efficiency ratings:
- Seasonal weather conditions: The colder the weather, the longer your high-efficiency furnace runs, and the sooner it will provide a return on investment. Therefore, higher AFUE ratings are most suitable in cold climates that demand more heating than cooling to sustain a pleasant indoor temperature.
- How long will you live there?: If you envision living in your home for some time, choosing a high-efficiency furnace may be a smart investment given that it will pay for itself over the next few years in energy savings. But, if you're going to move within the next few years, the extra cost of a higher AFUE-rated furnace would not be recommended.
- The cost of fuel: The impact of an efficient furnace is more evident when energy costs are 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
For help determining the ideal furnace system for your needs and budget, choose Service Experts. We can help you weigh 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 Service Experts Guarantee! For more information or to schedule a complimentary furnace installation estimate, please contact a Service Experts office near you.
