AFUE Ratings Guide

If you’re considering an upgrade to your furnace, an important first step is to determine an efficiency rating. That first choice will have an effect on your up-front costs and what you pay for home heating down the road. 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 standard for measuring 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 determined by calculating the ratio of the heat coming from your furnace to the amount of fuel it requires in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other factors that decrease efficiency. The result is expressed as a percentage, representing the amount of fuel converted into heat. 

Figuring out a furnace’s AFUE rating entails conducting a conventional test cycle to assess the heat output and fuel consumption. This test cycle is designed to simulate normal heating conditions in the course of the year, including both hot and cold periods. The heating system operates at maximum capacity for an extensive period to establish 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 past few decades with hopes to increase energy efficiency and reduce emissions that harm the ozone/atmosphere. In 2023, the minimum rating for new gas furnaces changed 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 power bills and curbs the environmental impact of heating your home. 

Why Do Gas Furnaces Jump from 80 to 90 AFUE? 

When browsing around for new furnaces, you may discover many models around 80 and 90 AFUE, but not much in between. This is as a result of the technology required to exceed 80 AFUE causes a considerable rise in performance. 

The 80 AFUE threshold has been the minimum expectation for gas furnaces in the U.S. 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 use more sophisticated technology to secure higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These technologies help the furnace pull heat from the fuel source more effectively, increasing efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at around 98.5 AFUE. 

How Do AFUE Ratings Impact Furnace Prices? 

The total price of a furnace with a higher AFUE rating is usually higher than that of a lower AFUE-rated furnace. Basically, more innovative technologies come with a higher price tag. The exact cost difference is based on the furnace make, size and efficiency rating. 

When considering the purchase price of a more efficient furnace, remember the ongoing energy savings that awaits you. The potential to save money on fuel bills for the next 10 years or longer will permit you to recoup the additional up-front investment. 

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

Although a higher AFUE rating results in more effective home heating and lower energy bills, this doesn’t necessarily mean everyone should choose a 95 AFUE furnace. Here are the factors to think about when contrasting costs and efficiency ratings:  

• Local weather: The colder the weather, 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 beneficial in cold climates that need more heating than cooling to maintain a comfy indoor temperature. 

• When do you plan to move?: If you picture living in your home for a long time, purchasing a high-efficiency furnace may be a smart investment given that it will pay for itself over the next few years in energy savings. On the other hand, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace may not be worth it. 

• Fuel costs: The benefit of an efficient furnace is more evident 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 

For help determining the ideal furnace system for your needs and budget, rely on Service Experts Heating, Air Conditioning & Plumbing. We can help you weigh 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! For more information or to schedule a free furnace installation estimate, please call a Service Experts office near you

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