AFUE Ratings Guide

If you’re thinking about upgrading your furnace, an early choice in the process is to decide on an efficiency rating. That rating selection will influence your up-front costs and what you pay for home heating in the future. 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 converts 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 fuel it consumes in the process. This calculation accounts for the energy lost through exhaust gases, radiation and other variables that reduce efficiency. The result is expressed as a percentage, representing the share of fuel converted into heat.

Calculating a heating system’s AFUE rating involves conducting a conventional test cycle to measure the heat output and fuel consumption. This test cycle is intended to simulate ordinary heating conditions in the course of the year, including both on and off periods. The heating system then functions at peak 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 last few decades in an attempt to encourage 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 called for furnaces to be rated 90 AFUE or higher. Better AFUE ratings cut down energy consumption, lowers energy 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 find many models around 80 and 90 AFUE, with little in between. This is because the technology required to exceed 80 AFUE triggers a substantial jump 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 transform 80% of the fuel they consume into heat, with the remaining 20% sacrificed to the atmosphere through the flue.

Gas furnaces must use more innovative technology to achieve higher AFUE ratings, such as two-stage or modulating gas valves, variable-speed blowers and secondary heat exchangers. These technologies help the furnace pull heat from the fuel source more effectively, boosting efficiency from 80 to 90 AFUE or higher. Today’s most popular furnaces cap out at approximately 98.5 AFUE.

How Do AFUE Ratings Affect Furnace Costs?

The 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 at a higher price. The exact cost difference depends on the furnace manufacturer, size and efficiency rating.

When thinking about the up-front cost of a more efficient furnace, don’t forget the ongoing energy savings that awaits you. The ability to save money on energy bills for the next decade or longer will permit you to recoup the extra up-front investment.

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

Though a higher AFUE rating translates into more efficient home heating and lower energy bills, this doesn’t necessarily mean everyone should buy a 95 AFUE furnace. Below are a few factors to consider when contrasting costs and efficiency ratings:

• Climate: The colder the temperatures, the longer your high-efficiency furnace runs, and the faster you will realize an overall savings from your investment. Because of this, higher AFUE ratings are most appropriate in cold climates that take more heating than cooling to keep a pleasant indoor temperature.
• When do you plan to move?: If you imagine living in your home for quite a while, choosing a high-efficiency furnace may be a good investment since it will pay for itself over the next few years in energy savings. On the other hand, if relocating is in your plans within the next couple of years, the extra cost of a higher AFUE-rated furnace would not be recommended.
• Energy prices: The affect of an efficient furnace is more noticeable when energy costs are higher. You’ll see the savings in your bottom line once your furnace converts a higher percentage of fuel into usable heat for your home.

Consider a New Furnace Today

If you’re looking for the best heating system for your needs and budget, select 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 know you’ll love working with Service Experts so much so that we offer a 100% satisfaction guarantee! To find out more or to schedule a no-cost furnace installation estimate, please call a Service Experts office near you.