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 first choice will impact your up-front costs and what you pay for home heating in the future. 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 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 determined by calculating the ratio of a furnace’s heat output to the fuel it utilizes in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other factors that decrease efficiency. The result is expressed as a percentage, representing the amount of fuel converted into heat. 

Figuring out a heating system’s AFUE rating involves conducting a common test cycle to assess the heat output and fuel consumption. This test cycle is intended to simulate normal heating conditions in the course of the year, including both hot and cold periods. The heating system then functions at maximum 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 slowly increased HVAC efficiency ratings over the last few decades with hopes to increase energy efficiency and reduce carbon monoxide from the 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 called for furnaces to be rated 90 AFUE or greater. Better AFUE ratings cut down energy consumption, lowers energy bills and curbs the environmental consequence of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When shopping 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 necessary to exceed 80 AFUE creates a considerable jump in performance. 

The 80 AFUE threshold has been the minimum expectation for gas furnaces in the United States 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 incorporate more sophisticated technology to secure higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and supplementary heat exchangers. These features help the furnace grab heat from the fuel source more effectively, raising efficiency from 80 to 90 AFUE or higher. Today’s top-rated furnaces cap out at around 98.5 AFUE. 

How Do AFUE Ratings Affect Furnace Prices? 

The total price of a furnace with a higher AFUE rating is usually more than that of a lower AFUE-rated furnace. Basically, more innovative technologies come with a higher price tag. The exact cost difference depends on the furnace manufacturer, size and efficiency rating. 

When evaluating the up-front cost of a more efficient furnace, remember the future energy savings that awaits you. The real chance to save money on fuel bills for the next ten years or longer will allow you to recoup the extra up-front investment. 

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

While a higher AFUE rating translates into better home heating and more affordable energy bills, we are not saying everyone should choose a 95 AFUE furnace. Here are the factors to think about when reviewing costs and efficiency ratings:  

  • Seasonal weather conditions: The colder the climate, the more your high-efficiency furnace runs, and thus, provides an earlier ROI. Therefore, higher AFUE ratings are most suitable in cold climates that require more heating than cooling to maintain a comfortable indoor temperature. 
  • When do you plan to move?: If you envision living in your home for some time, choosing a high-efficiency furnace could be a wise investment since it will pay for itself over time in energy savings. On the other hand, 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. 
  • Fuel costs: The affect of an efficient furnace is more noticeable 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 best furnace system for your needs and budget, turn to 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 steer 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 complimentary furnace installation estimate, please get in touch with a Service Experts office near you

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