What Are AFUE Ratings? Are They Important?

If you are like most people in Virginia, your home is either heated with a boiler or furnace. The difference between the two is that furnaces warm the air and then disperse that air though the house while boilers utilize water to provide steam for heating purposes or to provide hot water. The efficiency of furnaces and boilers is determined by the annual fuel utilization efficiency or AFUE.

What Is AFUE?

AFUE  is a measurement of the efficiency of the appliance when converting energy into fuel over the span of a normal year. The heating systems of yesteryear had incredibly low AFUE ratings; the range was between 56 and 70 percent. Today our units are much more efficient; some have ratings that are over 95 percent.

If your furnace, for illustrative purposes, has an AFUE rating of 80 percent, this signifies that this appliance is able to convert 80 percent of its energy into fuel for heating purposes. The other 20 percent, hopefully, will have exited via your chimney. Unfortunately, the AFUE rating doesn’t factor in the heat losses that occur because of duct systems, and that can account for as much as 35 percent of the energy output of the furnace.

Systems with high AFUE ratings (90-98.5 percent) are more efficient and therefore help save you money. By order of the Federal Trade Commission, all new furnaces and boilers must display their AFUE so that consumers can compare the efficiency ratings of the different models. To verify the proficiency of a high efficiency boiler or furnace, always look for the ENERGY STAR label; it is a government backed standard of quality.

Looking to upgrade your heating system? If so, a consultation with a heating technician is an important first step. Be sure to get your furnace properly sized and also have a discussion about ways of making your home more energy efficient. These efficiency improvements and proper sizing of your furnace will ensure that you get the smallest and most efficient unit for your home.

For more about AFUE ratings, or for general questions about heating and cooling, contact us HVAC & Plumbing Unlimited Heating & Air Conditioning. We serve Fairfax, Arlington and surrounding areas.