As of 2015, replacement parts for forced-air furnaces are available for purchase from dedicated HVAC websites such as MyHVACParts.com and online or in-store from Sears PartsDirect. Specific forced-air furnace parts are also available from manufacturers such as Goodman.
An electric forced air furnace's filter should be cleaned or replaced every month during heating seasons and once every three months for the rest of the year. A technician should also inspect and service the furnace once every year.
Air conditioning systems should be serviced at least once a year. Furnaces need to be serviced every one to five years, depending on the type of furnace. Experts recommend having air conditioning systems inspected in the spring.
As of September 2015, features of Central Boiler wood furnaces promote heat production, increase efficiency and keep maintenance costs low. For instance, the high-capacity water jacket supplies heat even after the wood has finished burning. The vent cap prevents evaporation.
An electric furnace may constantly blow cold air when it has a broken switch, thermostat problems or one or more broken heating elements. The high limit switch may be stuck open as well.
Standard fiberglass furnace filters should be changed once a month, and 3-inch high-efficiency furnace filters should be changed every three months. Washable furnace filters should be cleaned once a month.
A two-burner forced hot air furnace allows for two different heat settings. If conditions are very cold, then the second burner would turn on. Under warmer conditions, the furnace would run at the one-burner or lower setting.
Furnace air filters in a large home should be replaced about every three months. Individuals with larger homes may need to replace filters less often because the air has more room to circulate, thus reducing the amount of lint and dust that attaches to furnace air filters.
Air conditioners cannot be added to most furnaces, but they can be added to the ductwork to which the furnace connects. Those looking to save space can purchase integrated furnace and air conditioners.
Ducts on a forced-air furnace should be cleaned every three to five years if factors such as pets, smoking, home renovations and weather conditions have produced more dust in the home. In some cases, homeowners may choose to only clean ducts when debris, pests or mold affects the system.