What Is An AFUE Rating? Why Is It Important?

January 20, 2020

If you have shopped for home comfort equipment lately, you have probably encountered a dizzying array of acronyms along the way – SEER, EER, and HSPF, to name a few. One of the most common and important of those acronyms is AFUE – an energy efficiency rating used for heating appliances such as furnaces and boilers.

AFUE, which stands for Annual Fuel Utilization Efficiency, tells you how much of the fuel your equipment consumes translates directly to heat in your living space (versus how much energy is wasted along the way). For example, in an 86 AFUE unit, 86 percent of the fuel consumed by the machine goes to heating your home – the remaining 14 percent is lost en route.

One way to think about AFUE is to consider it in terms of the dollars you spend on fuel: In an 84 AFUE furnace, 84 cents of every dollar goes toward heating your Massachusetts home.

Typical furnace AFUE ratings

So what’s a typical AFUE rating for a furnace, for example? That depends on how old the unit is: efficiency standards were considerably lower 20+ years ago than they are today, and any furnace will lose efficiency over time.

Here are some efficiency guidelines for typical furnaces according to the U.S. Department of Energy:

Low-efficiency (older systems): 56-70 percent AFUE
Mid-efficiency (older or newer systems): 80-85 percent AFUE
High-efficiency (mostly newer systems): 90-98.5 percent AFUE

As of 2015, the minimum standard AFUE for new furnaces is 80 percent.

If your furnace is old and not well maintained, your AFUE could drop into the 60s or even 50s –a big reason why the decision to upgrade your heating equipment often pays for itself pretty quickly.

Real-world efficiency is about more than AFUE

Of course, AFUE doesn’t tell the whole efficiency story – proper heating system installation and periodic professional heating system maintenance are also extremely important pieces of the equation, as are several other factors. But knowing the AFUE rating remains an important bit of information when it comes time to invest in new high efficiency heating equipment for your Suffolk, Norfolk and Plymouth County MA home.

Looking for an energy efficient heating system replacement? We can help! Contact Scott Williams today for a FREE, no obligation estimate on a heating solution that’s sized for your home, budget, and lifestyle.