AFUE Ratings Guide

If you’re thinking about upgrading your furnace, an early choice in the process is to determine an efficiency rating. This will impact 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 measured by calculating the ratio of the heat coming from your furnace to the fuel it utilizes in the process. This calculation factors in the energy lost through exhaust gases, radiation and other elements that reduce efficiency. The result is expressed as a percentage, representing the amount of fuel converted into heat. 

Determining a furnace or boiler’s AFUE rating entails conducting a conventional test cycle to quantify the heat output and fuel consumption. This test cycle is intended to simulate ordinary heating conditions throughout 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 several decades in order to increase 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 greater. Better AFUE ratings lessen energy consumption, lowers energy bills and reduces the environmental impact of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When researching for new furnaces, you may find many models around 80 and 90 AFUE, with little in between. This is as a result of the technology needed to exceed 80 AFUE causes a significant leap in performance. 

The 80 AFUE threshold has been the minimum criteria for gas furnaces in the United States since the 1990s. At this level, furnaces transform 80% of the fuel they consume into heat, with the remaining 20% sacrificed to the atmosphere through the flue. 

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

How Do AFUE Ratings Impact Furnace Prices? 

The cost of a furnace with a higher AFUE rating is normally more than that of a lower AFUE-rated furnace. Not surprisingly, more innovative technologies come at a cost. The exact cost difference depends on the furnace make, size and efficiency rating. 

When evaluating the initial 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 10 years or longer will allow you to recoup the additional up-front investment. 

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

Although a higher AFUE rating leads to more effective home heating and more affordable energy bills, we are not saying everyone should buy a 95 AFUE furnace. Listed below are some factors to take into account when comparing costs and efficiency ratings:  

  • Local weather: The colder the weather, the more your high-efficiency furnace operates, and thus, provides an earlier ROI. Because of this, higher AFUE ratings are most suitable in cold climates that demand more heating than cooling to sustain a pleasant indoor temperature. 
  • When do you plan to move?: If you picture living in your home for quite a while, choosing a high-efficiency furnace could be a smart investment since it will pay for itself over the next few years in energy savings. On the other hand, if you’re going to move within the next few years, the extra cost of a higher AFUE-rated furnace may not be worth it. 
  • Fuel costs: The affect of an efficient furnace is more evident 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 

For help determining the perfect heating 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 inform 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 free furnace installation estimate, please contact a Service Experts office near you

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