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 influence your up-front costs and what you pay for home heating as time goes on. With this handy guide, you’ll understand more 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 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 measured by calculating the ratio of the heat coming from your furnace to the amount of fuel it consumes 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 proportion of fuel converted into heat.

Figuring out a furnace’s AFUE rating involves conducting a standard test cycle to quantify the heat output and fuel consumption. This test cycle is structured to simulate normal heating conditions throughout the year, including both in-season and out-of-season periods. The heating system is then run at maximum capacity for an extended period to determine 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 with hopes to increase energy efficiency and reduce emissions that harm the ozone/atmosphere. In 2023, the minimum rating for new gas furnaces changed 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 better. Better AFUE ratings lessen energy consumption, lowers power bills and reduces the environmental impact 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 because the technology required to exceed 80 AFUE forces a considerable leap 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 integrate more innovative technology to attain higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These technologies help the furnace pull heat from the fuel supply more effectively, boosting efficiency from 80 to 90 AFUE or higher. Today’s top-rated furnaces cap out at around 98.5 AFUE.

How Do AFUE Ratings Influence Furnace Prices?

The total price of a furnace with a higher AFUE rating is usually more than that of a lower AFUE-rated furnace. In the end, more sophisticated technologies come at a higher price. The exact cost difference will depend on the furnace manufacturer, size and efficiency rating.

When thinking about the purchase price of a more efficient furnace, remember the future energy savings that awaits you. The potential to save money on energy bills for the next 10 years or longer helps you to recoup the additional up-front investment.

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

Though a higher AFUE rating leads to more effective home heating and more affordable energy bills, we are not saying all homeowners should buy a 95 AFUE furnace. Listed below are some factors to take into account when reviewing costs and efficiency ratings:

  • Local weather: The colder the weather, the more frequently your high-efficiency furnace operates, and thus, provides an earlier ROI. Because of this, higher AFUE ratings are most appropriate in cold climates that require more heating than cooling to sustain a comfy indoor temperature.
  • How long you’ll live in this home: If you imagine living in your home for quite a while, purchasing a high-efficiency furnace may be a wise investment given that it will pay for itself over time in energy savings. But, if relocating is in your plans within the next couple of years, the extra cost of a higher AFUE-rated furnace probably does not make sense.
  • Fuel costs: The benefit of an efficient furnace is more evident if your energy costs are high. You’ll experience noticeable savings when your furnace converts a higher percentage of fuel into usable heat for your home.

Install a New Furnace Today

If you’re looking for the perfect furnace system for your needs and budget, select Service Experts Heating, Air Conditioning & Plumbing. We can help you weigh the up-front costs and long-term benefits of different AFUE ratings to steer your decision. We’re so confident you’ll be satisfied with our services that we offer a 100% satisfaction guarantee! To find out more or to schedule a complimentary furnace installation estimate, please contact a Service Experts office near you.