Household furnaces are used to heat your home through heated and circulated air. Furnaces are categorized by their fuel type usually either gas, oil or all electric. In addition to fuel type, furnaces are generally rated based on their efficiency.
Central furnace efficiency is measured by annual fuel utilization efficiency (AFUE). The Federal Trade Commission requires new furnaces to display their AFUE so consumers can compare heating efficiencies of various models. AFUE is a measure of how efficient the appliance is in converting the energy in its fuel to heat over the course of a typical year.
Specifically, AFUE is the ratio of annual heat output of the furnace compared to the total annual fossil fuel energy consumed by a furnace. An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere. AFUE doesn’t include the heat losses of the duct system or piping, which can be as much as 35% of the energy for output of the furnace when ducts are located in the attic.
An all-electric furnace has no flue loss through a chimney. The AFUE rating for an all-electric furnace or boiler is between 95% and 100%. The lower values are for units installed outdoors because they have greater jacket heat loss. However, despite their high efficiency, the higher cost of electricity in most parts of the country makes all-electric furnaces or boilers an uneconomic choice. If you are interested in electric heating, consider installing a heat pump system.
At Advanced Air and Heat we offer a number of furnace options with differing fuel types and furnace efficiency level. We also have in stock furnaces for indoor and outdoor installations. If you are looking to purchase a new furnace or repair an old furnace contact us!