AFUE Ratings Guide

If you’re thinking about upgrading your furnace, an early choice in the process is to decide on an efficiency rating. This will impact your up-front costs and what you pay for home heating in the coming years. 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 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 estimated by calculating the ratio of the heat coming from your furnace to the amount of fuel it consumes in the process. This calculation factors in the energy lost through exhaust gases, radiation and other variables that diminish efficiency. The result is displayed as a percentage, representing the amount of fuel converted into heat. 

Determining a furnace’s AFUE rating involves conducting a standard test cycle to quantify the heat output and fuel consumption. This test cycle is designed to simulate typical heating conditions over the year, including both on and off periods. The heating system then functions at peak 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 slowly increased HVAC efficiency ratings over the last several decades in order to encourage energy efficiency and reduce emissions that harm the ozone/atmosphere. 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 required furnaces to be rated 90 AFUE or better. Better AFUE ratings lessen energy consumption, lowers power bills and reduces the environmental impact 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 due to the technology needed to exceed 80 AFUE triggers a considerable rise in performance. 

The 80 AFUE threshold has been the minimum requirement 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 incorporate more innovative technology to attain higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and secondary heat exchangers. These solutions help the furnace pull heat from the fuel source more effectively, raising efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at about 98.5 AFUE. 

How Do AFUE Ratings Affect Furnace Prices? 

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

When considering the purchase price of a more efficient furnace, keep in mind the long-term energy savings that awaits you. The real chance to save money on utility bills for the next decade or longer will permit you to recoup the higher up-front investment. 

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

While a higher AFUE rating results in better home heating and more affordable energy bills, this doesn’t necessarily mean all homeowners should pick a 95 AFUE furnace. Below are a few factors to consider when reviewing costs and efficiency ratings:  

• Seasonal weather conditions: The colder the climate, the more frequently your high-efficiency furnace operates, and thus, provides an earlier ROI. For that reason, higher AFUE ratings are most beneficial in cold climates that require more heating than cooling to keep a comfy indoor temperature. 

• When do you plan to move?: If you envision living in your home for some time, buying a high-efficiency furnace may be a good investment since it will pay for itself over the next few years in energy savings. However, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace would not be recommended. 

• Energy prices: The impact of an efficient furnace is more noticeable if your energy costs are high. You’ll realize the savings each month when your furnace converts a higher percentage of fuel into usable heat for your home. 

Get a New Furnace Today 

When trying to find the perfect furnace 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’re so confident you’ll be satisfied with our services that we offer a 100% satisfaction guarantee! To find out more or to schedule a no-cost furnace installation estimate, please get in touch with a Service Experts office near you

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