AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, an important first step is to determine an efficiency rating. This 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 stands 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 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 output of heat from the furnace or boiler to the amount of gas or diesel it utilizes in the process. This calculation takes into account the energy lost through exhaust gases, radiation and other elements that reduce efficiency. The result is stated as a percentage, representing the amount of fuel converted into heat. 

Figuring out a furnace or boiler’s AFUE rating entails conducting a common test cycle to assess the heat output and fuel consumption. This test cycle is designed to simulate typical heating conditions throughout the year, including both hot and cold periods. The heating system is then run at maximum capacity for an extended 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 encourage energy efficiency and reduce greenhouse gas emissions. 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 called for furnaces to be rated 90 AFUE or better. Better AFUE ratings cut down energy consumption, lowers energy 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 notice many models around 80 and 90 AFUE, with little in between. This is as a result of the technology necessary to exceed 80 AFUE triggers a substantial leap in performance. 

The 80 AFUE threshold has been the minimum expectation for gas furnaces in the USA since the 1990s. At this level, furnaces turn 80% of the fuel they consume into heat, with the remaining 20% lost to the atmosphere through the flue. 

Gas furnaces must incorporate 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, increasing 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 Prices? 

The total price of a furnace with a higher AFUE rating is typically more than that of a lower AFUE-rated furnace. In the end, more advanced technologies come with a higher price tag. The exact cost difference is determined by the furnace brand, size and efficiency rating. 

When thinking about the purchase price of a more efficient furnace, keep in mind the long-term energy savings that awaits you. The ability to save money on energy bills for the next 10 years or longer will allow you to recoup the additional up-front investment. 

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

Though a higher AFUE rating leads to more effective home heating and lower energy bills, we are not recommending that all homeowners should choose a 95 AFUE furnace. Here are the factors to consider when contrasting costs and efficiency ratings:  

• Seasonal weather conditions: The colder the weather, the more frequently your high-efficiency furnace operates, and the faster you will realize an overall savings from your investment. Therefore, higher AFUE ratings are most beneficial in cold climates that demand more heating than cooling to keep a comfortable indoor temperature. 

• How long you’ll live in this home: If you envision living in your home for a long time, buying a high-efficiency furnace could be a smart investment since 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 would not be recommended. 

• Fuel costs: The impact of an efficient furnace is more pronounced when energy costs are higher. You’ll realize the savings each month 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 heating system for your needs and budget, select Service Experts Heating, Air Conditioning & Plumbing. We can help you sort out the up-front costs and long-term benefits of different AFUE ratings to guide your decision. We are so certain that you’ll love working with Service Experts that we offer a 100% satisfaction guarantee! To learn more or to schedule a no-cost furnace installation estimate, please contact a Service Experts office near you

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