AFUE Ratings Guide

If you’re realizing that it’s time to upgrade your furnace, one of the first steps 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 stands for Annual Fuel Utilization Efficiency. It is a measure of how efficiently a furnace or boiler switches 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 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 factors that reduce efficiency. The result is shown as a percentage, representing the share of fuel converted into heat. 

Calculating a heating system’s AFUE rating entails conducting a common 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 is then run 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 gradually increased HVAC efficiency ratings over the last few decades in an effort to promote 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 required furnaces to be rated 90 AFUE or higher. Better AFUE ratings reduce energy consumption, lowers energy bills and decreases the environmental impact of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When shopping for new furnaces, you may notice many models around 80 and 90 AFUE, and not a whole lot else to consider. This is due to the technology required to exceed 80 AFUE triggers a substantial leap in performance. 

The 80 AFUE threshold has been the minimum criteria 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% sacrificed to the atmosphere through the flue. 

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

How Do AFUE Ratings Influence Furnace Prices? 

The price of a furnace with a higher AFUE rating is normally higher than that of a lower AFUE-rated furnace. After all, more advanced technologies come at a higher price. The exact cost difference is determined by the furnace brand, size and efficiency rating. 

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

Is It Smart to 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 every homeowner should pick a 95 AFUE furnace. Listed below are some factors to take into account when evaluating costs and efficiency ratings:  

  • Local weather: The colder the climate, the longer your high-efficiency furnace operates, and the faster you will realize an overall savings from your investment. Therefore, higher AFUE ratings are most appropriate in cold climates that take more heating than cooling to keep a comfy indoor temperature. 
  • When do you plan to move?: If you imagine living in your home for some time, choosing a high-efficiency furnace may be a good investment because it will pay for itself over the coming 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 impact 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. 

Get a New Furnace Today 

When trying to find the best heating system for your needs and budget, rely on Service Experts Heating, Air Conditioning & Plumbing. We can help you sort out the initial costs and long-term benefits of different AFUE ratings to steer 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 complimentary furnace installation estimate, please contact a Service Experts office near you

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