AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, an early choice in the process is to determine an efficiency rating. That first choice will influence your up-front costs and what you pay for home heating as time goes on. With this handy guide, you’ll understand more about AFUE ratings and how they affect you. 

What Is an AFUE Rating? 

AFUE is short 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 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 a furnace’s heat output to the amount of fuel it requires in the process. This calculation factors in the energy lost through exhaust gases, radiation and other factors that diminish efficiency. The result is shown as a percentage, representing the amount of fuel converted into heat. 

Calculating a furnace or boiler’s AFUE rating includes conducting a standard test cycle to measure the heat output and fuel consumption. This test cycle is intended to simulate typical heating conditions over the year, including both in-season and out-of-season periods. The heating system operates at maximum capacity for an extended period to determine 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 last several decades in an effort to increase energy efficiency and reduce emissions that harm the ozone/atmosphere. 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 mandated furnaces to be rated 90 AFUE or greater. Better AFUE ratings reduce energy consumption, lowers energy 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, with little in between. This is as a result of the technology necessary to exceed 80 AFUE creates a substantial rise 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 turn 80% of the fuel they consume into heat, with the remaining 20% sacrificed to the atmosphere through the flue. 

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

How Do AFUE Ratings Impact Furnace Costs? 

The cost of a furnace with a higher AFUE rating is typically more than that of a lower AFUE-rated furnace. In the end, more advanced technologies come at a cost. The exact cost difference is based on the furnace make, size and efficiency rating. 

When thinking about the up-front cost of a more efficient furnace, keep in mind the long-term energy savings that awaits you. The potential to save money on utility bills for the next ten years or longer will permit you to recoup the extra up-front investment. 

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

While a higher AFUE rating results in more effective home heating and reduced energy bills, we are not recommending that everyone should pick a 95 AFUE furnace. Listed below are some factors to take into account when evaluating costs and efficiency ratings:  

  • Climate: The colder the temperatures, the more your high-efficiency furnace operates, and the sooner it will provide a return on investment. Therefore, higher AFUE ratings are most beneficial in cold climates that take more heating than cooling to sustain a comfy indoor temperature. 
  • When do you plan to move?: If you envision living in your home for many years, purchasing a high-efficiency furnace could be a good investment given that it will pay for itself over the next few years in energy savings. But, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace may not be worth it. 
  • The cost of fuel: The benefit of an efficient furnace is more noticeable when the price of fuel is higher. You’ll realize the savings each month once your furnace converts a higher percentage of fuel into usable heat for your home. 

Consider a New Furnace Today 

For help determining the perfect heating system for your needs and budget, select Service Experts Heating, Air Conditioning & Plumbing. We can help you sort out the up-front 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 learn more or to schedule a no-cost furnace installation estimate, please get in touch with a Service Experts office near you

  • How to Choose a Good HVAC System

    When it comes to keeping your home comfortable during every season, nothing is more critical than picking out the right heating, ventilation and air conditioning (HVAC) system. This choice influences your daily comfort, monthly utility bills and all-around home efficiency. But, with so many system... Continue reading

  • Year-End HVAC Maintenance List

    Once the air starts to get cold, you know it’s time to prepare your home for the cooler months ahead. Your heating system is critical to maintaining a cozy, warm environment. A well-maintained furnace delivers the comfort you crave while using a smaller amount of energy. Routine inspections also... Continue reading

  • 2024 Furnace and Air Conditioning Trends

    In the ever-evolving world of home HVAC, keeping up with the newest HVAC trends is imperative for homeowners looking to enhance their home’s comfort and efficiency. Going into 2024, the HVAC industry continues to innovate, bringing brand-new technologies and trends aimed at changing how... Continue reading