AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, an early choice in the process is to determine an efficiency rating. This will impact your up-front costs and what you pay for home heating as time goes on. 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 changes 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 a furnace’s heat output to the amount of gas or diesel it requires in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other variables that reduce efficiency. The result is displayed as a percentage, representing the share of fuel converted into heat. 

Figuring out a furnace’s AFUE rating entails conducting a common test cycle to measure the heat output and fuel consumption. This test cycle is designed to simulate ordinary heating conditions throughout the year, including both in-season and out-of-season periods. The heating system operates at peak capacity for an extensive period to determine 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 attempt 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 required furnaces to be rated 90 AFUE or higher. Better AFUE ratings lessen energy consumption, lowers power bills and curbs the environmental impact of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When browsing around for new furnaces, you may find many models around 80 and 90 AFUE, but not much in between. This is mainly because the technology needed to exceed 80 AFUE triggers a considerable rise in performance. 

The 80 AFUE threshold has been the minimum requirement 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 secure higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These solutions help the furnace pull heat from the fuel supply more effectively, improving efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at approximately 98.5 AFUE. 

How Do AFUE Ratings Impact Furnace Costs? 

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

When considering the up-front cost of a more efficient furnace, remember the future energy savings that awaits you. The ability to save money on energy bills for the next decade 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? 

Although a higher AFUE rating results in better home heating and reduced energy bills, we are not saying all homeowners should pick a 95 AFUE furnace. Here are the factors to consider when evaluating costs and efficiency ratings:  

• Local weather: The colder the climate, the more your high-efficiency furnace operates, and thus, provides an earlier ROI. For that reason, higher AFUE ratings are most beneficial in cold climates that demand more heating than cooling to sustain a comfortable indoor temperature. 

• How long will you live there?: If you picture living in your home for a long time, choosing a high-efficiency furnace may be a wise investment because it will pay for itself over the coming 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. 

• Energy prices: The benefit of an efficient furnace is more pronounced when energy costs are 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 

For help determining the ideal furnace system for your needs and budget, choose Service Experts Heating, Air Conditioning & Plumbing. We can help you weigh the initial costs and long-term benefits of different AFUE ratings to guide your decision. We know you’ll love working with Service Experts so much so that we offer a 100% satisfaction guarantee! For more information or to schedule a free furnace installation estimate, please contact a Service Experts office near you

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