AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, one of the first steps is to settle on an efficiency rating. That rating selection will have an effect on your up-front costs and what you pay for home heating in the future. Use this guide to learn more about AFUE ratings and how they affect you. 

What Is an AFUE Rating? 

AFUE is short for Annual Fuel Utilization Efficiency. It is a measure of 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 determined by calculating the ratio of the heat coming from your furnace to the amount of 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 displayed as a percentage, representing the amount of fuel converted into heat. 

Determining a heating system’s AFUE rating involves conducting a conventional 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 hot and cold periods. The heating system is then run at full 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 with hopes to promote energy efficiency and reduce carbon monoxide from the 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 called for furnaces to be rated 90 AFUE or better. Better AFUE ratings lessen energy consumption, lowers energy bills and decreases the environmental consequence of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When researching for new furnaces, you may discover many models around 80 and 90 AFUE, but not much in between. This is because the technology necessary to exceed 80 AFUE triggers a considerable jump 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% forfeited to the atmosphere through the flue. 

Gas furnaces must use more sophisticated technology to attain higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These solutions help the furnace extract heat from the fuel source 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 Prices? 

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

When thinking about the up-front cost of a more efficient furnace, don’t forget the long-term energy savings that awaits you. The ability to save money on utility bills for the next ten years or longer will definitely allow you to recoup the higher up-front investment. 

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

Though a higher AFUE rating leads to more efficient home heating and lower energy bills, we are not saying every homeowner should pick a 95 AFUE furnace. Here are the factors to think about when contrasting costs and efficiency ratings:  

• Climate: The colder the temperatures, the more your high-efficiency furnace runs, and the sooner it will provide a return on investment. For that reason, higher AFUE ratings are most suitable in cold climates that demand more heating than cooling to maintain a pleasant indoor temperature. 

• How long you’ll live in this home: If you imagine living in your home for some time, choosing 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. 

• Energy prices: The impact of an efficient furnace is more pronounced when the price of fuel is higher. You’ll see the savings in your bottom line as your furnace converts a higher percentage of fuel into usable heat for your home. 

Consider a New Furnace Today 

When trying to find the best 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 guide 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 free furnace installation estimate, please call a Service Experts office near you

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