What Does AFUE Mean?

Two technicians performing diagnostic tests on a customer’s home HVAC unit.

When browsing new HVAC equipment or searching for answers related to home heating and cooling, there are numerous acronyms you will encounter – with HVAC being the first! In our industry, we use acronyms to shorten many common terms, including types of equipment, important measures, and efficiency ratings.

Many homeowners have questions about what these letters stand for, and if you’re shopping for a new furnace, here’s one acronym question you may have asked – what does AFUE mean? Below, Energy Savers decodes this essential HVAC acronym and explains why it matters to your new heating system purchase.

What Does AFUE Mean?


AFUE is an acronym that stands for annual fuel utilization efficiency. This is the measure used to express the efficiency of combustion space heating equipment such as natural gas furnaces and boilers. AFUE shows the equipment’s efficiency when it comes to converting fuel to heat for your home, measured over a typical year’s time.

While it’s helpful to know what this abbreviation stands for, you may still wonder what AFUE means in layman’s terms? Simply put, AFUE represents the amount of heat a furnace or boiler produces in comparison to the total amount of energy the appliance consumes to do this job. Divide the furnace’s annual heat output by its annual fuel consumption and the quotient is the unit’s annual fuel utilization efficiency rating.

Now that we’ve discussed what an AFUE rating means, let’s explain this furnace efficiency rating in more detail. When a gas furnace runs, fuel is combusted to generate heating energy that is used to warm the home’s air. As no fuel-burning furnace is 100% efficient, some waste results from the process. The majority of the energy created through combustion is put to good use by the furnace, but a small portion of this energy is lost and exhausted through the flue or elsewhere. AFUE shows how much of the fuel used by the furnace ends up as heating energy used by the system to heat spaces and how much of that energy is lost during operation.

AFUE is always expressed as a percentage. The minimum AFUE rating for new gas furnaces installed in Georgia and Alabama homes is 80% and 83% for oil furnaces, according to federal appliance standards. However, models are available that offer AFUE ratings as high as 98.5% for high-efficiency furnaces which use gas and 95% for oil furnaces. 80% to 83% AFUE is considered standard or mid-efficiency, while ratings of 90% AFUE and up are considered high efficiency.

AFUE & Your New Furnace


AFUE ratings are important when shopping for a new furnace for your home. The AFUE of any furnace will play a role in the initial cost of the unit as well as the cost to operate it over the equipment’s service life. As you choose a furnace, it’s important to consider your budget for the initial purchase as well as your budget for heating costs.

In general, a lower AFUE furnace will cost less to purchase than high-efficiency heating equipment. Standard efficiency furnaces are typically basic systems that don’t offer the advanced technologies that make higher AFUE ratings possible. High-efficiency furnace models incorporate features that allow for more energy-efficient operation, which increases the cost of the system. These features include:

Variable speed operation, which allows adjustment in blower speed for precision control of airflow based on the heating needs of the home.
Modulating furnaces, which use a modulating gas valve and electronic controls to adjust gas supply and burner flames for better temperature regulation.
Secondary heat exchanger, which helps the furnace capture more heat energy from combustion and use it for warming the air (found in condensing furnace models).
While buying a high-efficiency furnace costs more upfront, this type of unit will cost less to operate than a standard efficiency model. This is because more of the fuel consumed is put to use heating your home and less fuel is wasted in the process. Homeowners can expect lower energy bills when using a high-efficiency furnace versus a standard efficiency model. Over the 15 to 20 years the furnace is in use, this savings can make up and often exceed the difference in initial purchase cost so that a high-efficiency furnace ultimately costs less over time.

Furnace Installation in Columbus, GA and Opelika, AL


Now that you understand what an AFUE rating means, you can see how this efficiency rating plays into purchase decisions when buying a new furnace. If you have more questions about AFUE rating or are ready to shop for your home’s new furnace, contact Energy Savers today!

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