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. That rating selection will impact your up-front costs and what you pay for home heating as time goes on. 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 an industry-standard measurement for how efficiently a furnace or boiler changes 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 determined by calculating the ratio of the output of heat from the furnace or boiler to the amount of fuel it requires in the process. This calculation takes into account the energy lost through exhaust gases, radiation and other variables that reduce efficiency. The result is displayed as a percentage, representing the share of fuel converted into heat. 

Figuring out a heating system’s AFUE rating entails conducting a conventional test cycle to measure the heat output and fuel consumption. This test cycle is designed to simulate typical heating conditions throughout the year, including both in-season and out-of-season periods. The heating system operates at maximum capacity for a prolonged 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 last few decades with hopes to encourage energy efficiency and reduce carbon monoxide from the 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 mandated furnaces to be rated 90 AFUE or better. Better AFUE ratings cut down energy consumption, lowers energy bills and curbs 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, and not a whole lot else to consider. This is as a result of the technology needed to exceed 80 AFUE forces a considerable jump in performance. 

The 80 AFUE threshold has been the minimum expectation for gas furnaces in the USA since the 1990s. At this level, furnaces convert 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 attain higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and alternate heat exchangers. These features 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 around 98.5 AFUE. 

How Do AFUE Ratings Impact Furnace Prices? 

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

When considering the initial cost of a more efficient furnace, don’t forget the ongoing energy savings that awaits you. The potential to save money on fuel bills for the next ten years or longer helps you to recoup the higher up-front investment. 

Does It Make Sense to Buy a Furnace with the Highest AFUE Rating Possible? 

While a higher AFUE rating leads to better home heating and more affordable energy bills, we are not recommending that every homeowner should pick a 95 AFUE furnace. Here are the factors to consider when comparing costs and efficiency ratings:  

  • Local weather: The colder the climate, the more your high-efficiency furnace runs, and the faster you will realize an overall savings from your investment. For that reason, higher AFUE ratings are most suitable in cold climates that demand more heating than cooling to sustain a comfortable indoor temperature. 
  • How long will you live there?: If you imagine living in your home for a long time, buying a high-efficiency furnace might be a good investment because 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 probably does not make sense. 
  • Energy prices: The benefit of an efficient furnace is more pronounced when the price of fuel is higher. You’ll experience noticeable savings once your furnace converts a higher percentage of fuel into usable heat for your home. 

Get a New Furnace Today 

For help determining the perfect furnace system for your needs and budget, select Service Experts Heating, Air Conditioning & Plumbing. We can help you weigh the up-front costs and long-term benefits of different AFUE ratings to guide your decision. We are so certain that you’ll love working with Service Experts that we offer a 100% satisfaction guarantee! To find out more or to schedule a no-cost furnace installation estimate, please contact a Service Experts office near you

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