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 have an effect on your up-front costs and what you pay for home heating in the future. 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 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 determined by calculating the ratio of the heat coming from your furnace to the amount of gas or diesel it consumes in the process. This calculation factors in the energy lost through exhaust gases, radiation and other elements that diminish efficiency. The result is shown as a percentage, representing the amount of fuel converted into heat. 

Determining a furnace or boiler’s AFUE rating includes conducting a conventional test cycle to measure the heat output and fuel consumption. This test cycle is structured to simulate normal heating conditions in the course of the year, including both on and off periods. The heating system then functions 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 slowly increased HVAC efficiency ratings over the last several decades with hopes to promote energy efficiency and reduce greenhouse gas emissions. 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 called for furnaces to be rated 90 AFUE or higher. 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 searching for new furnaces, you may notice many models around 80 and 90 AFUE, but not much in between. This is mainly because the technology necessary to exceed 80 AFUE creates a substantial rise in performance. 

The 80 AFUE threshold has been the minimum expectation 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 incorporate more advanced technology to secure higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and supplementary heat exchangers. These technologies help the furnace extract heat from the fuel source more effectively, improving efficiency from 80 to 90 AFUE or higher. Today’s best furnaces cap out at around 98.5 AFUE. 

How Do AFUE Ratings Influence Furnace Costs? 

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

When considering the up-front cost of a more efficient furnace, remember the future energy savings that awaits you. The real chance to save money on utility bills for the next decade or longer helps you to recoup the extra up-front investment. 

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

Though a higher AFUE rating results in better home heating and lower energy bills, we are not saying everyone should buy a 95 AFUE furnace. Here are the factors to consider when contrasting costs and efficiency ratings:  

• Climate: The colder the temperatures, the more your high-efficiency furnace operates, and the faster you will realize an overall savings from your investment. Because of this, higher AFUE ratings are most suitable in cold climates that need more heating than cooling to sustain a comfy indoor temperature. 

• How long you’ll live in this home: If you envision living in your home for many years, buying a high-efficiency furnace might be a good investment given that it will pay for itself over time in energy savings. But, if you’re going to move within the next few years, the extra cost of a higher AFUE-rated furnace probably does not make sense. 

• Fuel costs: The impact of an efficient furnace is more pronounced if your energy costs are high. You’ll see the savings in your bottom line when your furnace converts a higher percentage of fuel into usable heat for your home. 

Consider a New Furnace Today 

If you’re looking for the ideal furnace system for your needs and budget, rely on 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! To find out more or to schedule a free furnace installation estimate, please contact a Service Experts office near you

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