AFUE Ratings Guide

If you’re considering an upgrade to your furnace, an important first step is to determine an efficiency rating. This will have an effect on your up-front costs and what you pay for home heating in the future. 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 a measure of how efficiently a furnace or boiler switches fuel into heat for your home within a 12-month period. 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 the heat coming from your furnace to the amount of gas or diesel it requires in the process. This calculation takes into account the energy lost through exhaust gases, radiation and other factors that decrease efficiency. The result is stated as a percentage, representing the share of fuel converted into heat. 

Figuring out a furnace or boiler’s AFUE rating includes conducting a standard test cycle to quantify the heat output and fuel consumption. This test cycle is designed to simulate ordinary heating conditions over the year, including both on and off periods. The heating system is then run 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 gradually increased HVAC efficiency ratings over the past few decades in an effort to promote energy efficiency and reduce greenhouse gas emissions. 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 called for furnaces to be rated 90 AFUE or better. 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 discover many models around 80 and 90 AFUE, and not a whole lot else to consider. This is due to the technology required to exceed 80 AFUE forces a substantial rise in performance. 

The 80 AFUE threshold has been the minimum requirement 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% sacrificed to the atmosphere through the flue. 

Gas furnaces must integrate more innovative technology to secure higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and supplementary heat exchangers. These solutions help the furnace pull heat from the fuel supply more effectively, increasing efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at about 98.5 AFUE. 

How Do AFUE Ratings Determine Furnace Costs? 

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

When considering the initial cost of a more efficient furnace, don’t forget the future energy savings that awaits you. The real chance to save money on energy bills for the next decade or longer helps you to recoup the extra up-front investment. 

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

Though a higher AFUE rating translates into more efficient home heating and lower energy bills, this doesn’t necessarily mean every homeowner should purchase a 95 AFUE furnace. Listed below are some factors to consider when contrasting costs and efficiency ratings:  

• Climate: The colder the temperatures, the more frequently your high-efficiency furnace runs, and thus, provides an earlier ROI. Because of this, higher AFUE ratings are most appropriate in cold climates that take more heating than cooling to maintain a comfy indoor temperature. 

• How long you’ll live in this home: If you envision living in your home for quite a while, choosing a high-efficiency furnace might be a smart investment since it will pay for itself over time in energy savings. However, 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 impact of an efficient furnace is more pronounced if your energy costs are high. You’ll realize the savings each month as your furnace converts a higher percentage of fuel into usable heat for your home. 

Get a New Furnace Today 

For help determining the best furnace system for your needs and budget, choose Service Experts Heating, Air Conditioning & Plumbing. We can help you figure out 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! For more information or to schedule a no-cost furnace installation estimate, please contact a Service Experts office near you

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