AFUE Ratings Guide

If you’re thinking about upgrading your furnace, one of the first steps is to decide on an efficiency rating. This will have an effect on your up-front costs and what you pay for home heating in the future. Use this guide to learn more 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 converts 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 the heat coming from your furnace to the amount of gas or diesel 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 shown as a percentage, representing the proportion of fuel converted into heat.

Determining a furnace’s AFUE rating involves conducting a standard test cycle to assess the heat output and fuel consumption. This test cycle is designed to simulate ordinary heating conditions over the year, including both on and off periods. The heating system operates at full capacity for an extensive period to determine its peak performance.

What Is the Minimum AFUE Rating in 2023?

The U.S. Department of Energy (DOE) has steadily 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 was set 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 higher. Better AFUE ratings lessen energy consumption, lowers energy bills and curbs the environmental consequence of heating your home.

Why Do Gas Furnaces Jump from 80 to 90 AFUE?

When shopping for new furnaces, you may discover many models around 80 and 90 AFUE, but not much in between. This is due to the technology necessary to exceed 80 AFUE triggers a substantial 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 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 advanced 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 supply more effectively, increasing efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at about 98.5 AFUE.

How Do AFUE Ratings Impact Furnace Prices?

The cost of a furnace with a higher AFUE rating is usually more than that of a lower AFUE-rated furnace. In the end, more innovative technologies come at a higher price. The exact cost difference will depend on the furnace manufacturer, size and efficiency rating.

When thinking about the purchase price of a more efficient furnace, remember the future energy savings that awaits you. The real chance to save money on fuel bills for the next 10 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?

Though a higher AFUE rating leads to more efficient home heating and more affordable energy bills, we are not recommending that all homeowners should pick a 95 AFUE furnace. Below are a few factors to take into account when contrasting costs and efficiency ratings:

• Climate: The colder the temperatures, 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 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 quite a while, choosing a high-efficiency furnace could be a smart investment since it will pay for itself over the coming years in energy savings. But, 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.
• The cost of fuel: The impact of an efficient furnace is more pronounced when energy costs are higher. You’ll see the savings in your bottom line as your furnace converts a higher percentage of fuel into usable heat for your home.

Install a New Furnace Today

When trying to find the best heating system for your needs and budget, turn to Service Experts Heating, Air Conditioning & Plumbing. We can help you weigh the initial costs and long-term benefits of different AFUE ratings to guide your decision. We know you’ll love working with Service Experts so much so that we offer a 100% satisfaction guarantee! To learn more or to schedule a free furnace installation estimate, please call a Service Experts office near you.