To indicate how efficient a gas furnace is—i.e. how well it converts natural gas into heating power—manufacturers use a measure called annual fuel utilization efficiency or AFUE. This is a percentage that shows how much of the furnace’s supply of gas is changed into actual heat and how much is lost to exhaust or natural heat bleed. For example, a furnace with an AFUE of 80% converts 100 units of fuel into 80 units of heat, with 20 units wasted. The measurement is averaged out over a year rather than through a single test.

Although a high AFUE rating doesn’t guarantee that a furnace will save a homeowner money (a poor choice of furnace will still end up wasting power) it’s the starting place for anyone who wants to cut down on utility bills. The standard furnace today has between 85% and 90% AFUE.

If you are looking for one of the highest efficiency furnaces on the market, we recommend you consider a condensing furnace, which can score in the high 90s for AFUE. That can mean a huge change in your energy bills each winter.

How does a condensing furnace perform this efficiently? Because it takes the exhaust gases in the furnace and squeezes even more energy from them. After the combustion gas is condensed inside the heat exchanger of the furnace, the remaining vapor isn’t just sent out the flue as in other furnaces. It’s instead sent to a second heat exchanger, where it’s condensed to release more heat. The tiny amount remaining is then sent out as exhaust.

Although a condensing furnace costs more than a standard one, the savings will usually let it pay for its installation after only a few years. Talk to our heating professionals and they will help you determine if a condensing furnace is a good choice for your next home heating system.

Advanced Mechanical Services offers furnace installation in Cliffside Park, NJ and throughout the Northern New Jersey Area.