AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, one of the first steps is to decide on an efficiency rating. That first choice 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 a measure of how efficiently a furnace or boiler changes 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 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 variables that reduce efficiency. The result is expressed as a percentage, representing the share of fuel converted into heat. 

Calculating a heating system’s AFUE rating includes conducting a common test cycle to quantify the heat output and fuel consumption. This test cycle is structured to simulate ordinary heating conditions over the year, including both on and off periods. The heating system operates at peak capacity for a prolonged 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 effort to encourage energy efficiency and reduce carbon monoxide from the 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 required furnaces to be rated 90 AFUE or higher. Better AFUE ratings cut down energy consumption, lowers energy 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 mainly because the technology necessary to exceed 80 AFUE creates a considerable jump 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% forfeited to the atmosphere through the flue. 

Gas furnaces must use more advanced technology to achieve higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These features help the furnace pull heat from the fuel supply more effectively, raising efficiency from 80 to 90 AFUE or higher. Today’s top-rated furnaces cap out at approximately 98.5 AFUE. 

How Do AFUE Ratings Affect Furnace Prices? 

The total price of a furnace with a higher AFUE rating is normally more than that of a lower AFUE-rated furnace. Basically, more advanced technologies come at a cost. The exact cost difference depends on the furnace brand, size and efficiency rating. 

When thinking about the purchase price of a more efficient furnace, keep in mind the future energy savings that awaits you. The real chance to save money on energy bills for the next 10 years or longer helps you to recoup the higher up-front investment. 

Should You Buy a Furnace with the Highest AFUE Rating Possible? 

Although a higher AFUE rating translates into more efficient home heating and lower energy bills, we are not saying all homeowners should pick a 95 AFUE furnace. Listed below are some factors to take into account when contrasting costs and efficiency ratings:  

• Local weather: The colder the temperatures, the more your high-efficiency furnace operates, and thus, provides an earlier ROI. For that reason, higher AFUE ratings are most suitable in cold climates that require 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 some time, purchasing a high-efficiency furnace may be a smart investment given that it will pay for itself over time 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. 

• The cost of fuel: The impact of an efficient furnace is more noticeable when energy costs are higher. You’ll realize the savings each month once 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, choose Service Experts Heating, Air Conditioning & Plumbing. We can help you figure out the initial 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! For more information or to schedule a complimentary furnace installation estimate, please contact a Service Experts office near you

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