AFUE Ratings Guide

If you’re considering an upgrade to your furnace, one of the first steps is to settle on an efficiency rating. That first choice will have an effect on 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 measure of 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 a furnace’s heat output to the fuel it utilizes in the process. This calculation takes into account the energy lost through exhaust gases, radiation and other variables that reduce efficiency. The result is displayed as a percentage, representing the amount of fuel converted into heat.

Figuring out a furnace or boiler’s AFUE rating involves conducting a conventional test cycle to measure the heat output and fuel consumption. This test cycle is intended to simulate normal heating conditions throughout the year, including both hot and cold periods. The heating system then functions at full capacity for an extensive period to define 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 few decades in an effort to improve energy efficiency and reduce emissions that harm the ozone/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 mandated furnaces to be rated 90 AFUE or higher. Better AFUE ratings cut down energy consumption, lowers power bills and curbs the environmental consequence of heating your home.

Why Do Gas Furnaces Jump from 80 to 90 AFUE?

When searching for new furnaces, you may notice many models around 80 and 90 AFUE, with little in between. This is mainly because the technology necessary to exceed 80 AFUE forces a significant jump in performance.

The 80 AFUE threshold has been the minimum expectation for gas furnaces in the USA 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 incorporate 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 grab heat from the fuel source more effectively, boosting efficiency from 80 to 90 AFUE or higher. Today’s best furnaces cap out at around 98.5 AFUE.

How Do AFUE Ratings Impact Furnace Prices?

The price of a furnace with a higher AFUE rating is normally higher than that of a lower AFUE-rated furnace. After all, more sophisticated technologies come at a higher price. The exact cost difference is based on the furnace make, size and efficiency rating.

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

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

While a higher AFUE rating results in more effective home heating and lower energy bills, this doesn’t necessarily mean everyone should choose a 95 AFUE furnace. Here are the factors to take into account when reviewing costs and efficiency ratings:

• Seasonal weather conditions: The colder the climate, the longer your high-efficiency furnace operates, 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 maintain a comfortable indoor temperature.
• How long will you live there?: If you picture living in your home for quite a while, choosing a high-efficiency furnace could be a wise investment given that it will pay for itself over the coming years in energy savings. But, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace probably does not make sense.
• The cost of fuel: The impact of an efficient furnace is more evident when energy costs are 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 best furnace system for your needs and budget, select Service Experts Heating & Air Conditioning. We can help you sort out the up-front costs and long-term benefits of different AFUE ratings to inform 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.