AFUE Ratings Guide

If you’re thinking about upgrading your furnace, an important first step is to decide on an efficiency rating. This 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 stands for Annual Fuel Utilization Efficiency. It is a measure of how efficiently a furnace or boiler changes fuel into heat for your home within 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 a furnace’s heat output to the amount of gas or diesel it consumes in the process. This calculation takes into account 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.

Calculating a furnace or boiler’s AFUE rating includes conducting a common test cycle to measure the heat output and fuel consumption. This test cycle is intended to simulate typical heating conditions in the course of the year, including both in-season and out-of-season periods. The heating system then functions at full 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 several decades in an effort to promote energy efficiency and reduce carbon monoxide from the 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 cut down 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 browsing around 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 considerable rise in performance.

The 80 AFUE threshold has been the minimum requirement 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% forfeited 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 techniques help the furnace grab heat from the fuel supply more effectively, increasing efficiency from 80 to 90 AFUE or higher. Today’s best furnaces cap out at approximately 98.5 AFUE.

How Do AFUE Ratings Influence Furnace Prices?

The total price of a furnace with a higher AFUE rating is typically more than that of a lower AFUE-rated furnace. In the end, more sophisticated technologies come at a higher price. The exact cost difference is determined by the furnace make, 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 ability to save money on energy bills for the next ten years or longer will definitely allow 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 results in more effective home heating and lower energy bills, this doesn’t necessarily mean every homeowner should purchase a 95 AFUE furnace. Here are the factors to think about when evaluating costs and efficiency ratings:

• Climate: The colder the weather, the longer your high-efficiency furnace operates, and the sooner it will provide a return on investment. Because of this, higher AFUE ratings are most suitable in cold climates that demand more heating than cooling to keep a comfortable indoor temperature.
• How long will you live there?: If you imagine living in your home for a long time, purchasing a high-efficiency furnace may be a wise investment since it will pay for itself over the coming years in energy savings. But, if you plan to move in the near future, the extra cost of a higher AFUE-rated furnace would not be recommended.
• Fuel costs: The benefit of an efficient furnace is more noticeable if your energy costs are high. You’ll experience noticeable savings when your furnace converts a higher percentage of fuel into usable heat for your home.

Get a New Furnace Today

If you’re looking for the best furnace system for your needs and budget, rely on Service Experts Heating & Air Conditioning. We can help you sort out the up-front 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 find out more or to schedule a no-cost furnace installation estimate, please contact a Service Experts office near you.