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. This 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 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 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 elements that reduce efficiency. The result is stated as a percentage, representing the share of fuel converted into heat.

Determining a heating system’s AFUE rating entails conducting a standard test cycle to measure the heat output and fuel consumption. This test cycle is structured to simulate normal heating conditions in the course of the year, including both on and off periods. The heating system then functions 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 slowly increased HVAC efficiency ratings over the last several decades in an attempt to promote energy efficiency and reduce emissions that harm the ozone/atmosphere. 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 mandated furnaces to be rated 90 AFUE or higher. Better AFUE ratings cut down energy consumption, lowers utility bills and reduces 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, with little in between. This is because the technology required to exceed 80 AFUE causes a significant 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% sacrificed to the atmosphere through the flue.

Gas furnaces must integrate more advanced technology to achieve higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and supplementary heat exchangers. These features 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 Impact Furnace Costs?

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 at a higher price. The exact cost difference is based on the furnace make, size and efficiency rating.

When considering the up-front cost of a more efficient furnace, keep in mind the ongoing energy savings that awaits you. The ability to save money on energy 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 more efficient home heating and more affordable energy bills, this doesn’t necessarily mean everyone should buy a 95 AFUE furnace. Below are a few factors to consider when evaluating costs and efficiency ratings:

• Local weather: The colder the climate, the longer your high-efficiency furnace runs, and the faster you will realize an overall savings from your investment. Because of this, higher AFUE ratings are most appropriate in cold climates that need more heating than cooling to maintain a pleasant indoor temperature.
• When do you plan to move?: If you picture living in your home for some time, buying a high-efficiency furnace might be a smart investment since it will pay for itself over time in energy savings. However, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace would not be recommended.
• Energy prices: The affect of an efficient furnace is more evident when the price of fuel is higher. You’ll experience noticeable savings as 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 ideal furnace system for your needs and budget, select Service Experts Heating & Air Conditioning. We can help you weigh 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 call a Service Experts office near you.