When looking for a furnace, a buyer should look for one with variable-speed technology, two-stage heating, efficient operation and one made from a reputable manufacturer. A furnace with a warranty and quiet operation is also recommended. There are also extra accessories buyers may desire, such as thermostats and air cleaners.
Furnaces with variable-speed technology save energy while keeping the temperature comfortable. Variable-speed motors don't consume as much energy as standard furnace motors. Another advantage of variable-speed technology is it can reduce the chances of mold growth while improving indoor air quality.
Two-stage heating furnaces reduce drastic temperature swings during the colder months of the year. The first stage of the heating process involves the furnace operating at roughly 70 percent of its total heating capacity, which is usually adequate for mild winter days. The second stage is activated when the temperatures drop.
Efficient furnaces save more on energy costs. The Annual Fuel Utilization Efficiency number indicates how efficient a furnace is at changing fuel to energy. Energy Star furnaces are also some of the more efficient models because they meet the Environmental Protection Agency's energy standards.
Buyers should also look for furnaces that come with a warranty. The heat exchanger may have a 20-year warranty while the other components might have a five-year limited warranty.