Is There a Roof-Mounted Furnace?

Mounting

• Mounting a rooftop furnace requires rigging the unit to the top of the house with cable slings. Most furnaces have holes available for sliding pipes through. Attach the slings to the pipes for lifting the unit onto the roof. Skids, a type of steel girders, are what normally hold a mounted rooftop furnace in place. Make sure to place the mounted furnace on an even-leveled roof. Also, homeowners need to make sure their roofs are capable of handling the weight of a rooftop furnace before permanently mounting the unit.

Fossil Fuel vs. Electric

• Modern rooftop furnaces operate on electricity or fossil fuels such as natural gas and oil. Fossil fuel furnaces heat air with burners before the air enters the house duct system. Electric furnaces use electric forced-air energy to heat a house. While natural gas and oil furnaces are usually competitive in terms of cost-effectiveness, some regions of the United States and Canada have a limited amount of access to fossil fuels. In these instances, it makes more economical sense to own an electric rooftop furnace. The pricing of fossil fuels and electric furnaces varies from region to region.

Forced-air Systems

• Rooftop furnaces use forced-air systems to provide space heating. A forced-air system takes heat from the rooftop furnace and distributes the heated air throughout the house via ducts and vents. Forced-air systems are common in North American homes since they also distribute cool air during the summer. The forced-air system's air handler has a blower to help force the heat to the ducts. Also, forced-air systems have flue pipes to allow the rooftop furnace's combustion gases to escape to the outdoors.

Packaged Units

• When rooftop furnaces are part of a packaged HVAC system, they share a cabinet with an air conditioning unit. While rooftop furnaces fluctuate between fossil fuels and electricity, rooftop air conditioners always run on electricity. Packaged rooftop units are usually found on commercial buildings, but they are also used for apartment buildings and large houses. The British thermal unit heating output of packaged rooftop furnaces ranges between 30,000 to 500,000.