Limitations of Use of a Gas-fired Furnace

Gas Lines

• If you want to use a natural gas furnace, you will need access to natural gas lines. These lines are installed over broad areas and allow you to use the gas for stove tops, dryers and other uses. If natural gas is not available in your neighborhood, you will not be able to use a furnace. However, you might still be able to install a propane tank and use a propane substitute instead, albeit at a higher price.

Condensation Lines

• Gas furnaces tend to produce condensation, especially the newer and more efficient versions that take heat from the exhaust air. These moisture cannot leak back into the furnace, it requires a condensation line in order to drain properly. This means you must use not only the drainage pan and line of the furnace but also a drain either in your floor and wall to get rid of the condensation permanently. Without access to such a drainage system you cannot use the furnace.

Exhaust Pipes and Supply Vents

• Gas furnaces need two types of air ducts, exhaust and supply. Exhaust pipes typically exit through the attic or roof. These pipes are necessary, because gas furnace exhaust contains carbon monoxide and other dangerous fumes. The supply vent attaches a wall and brings in air from outside for the burners. The burners need a fresh source of oxygen to operate, so this attachment is also necessary.

Sizing

• Sizing refers to what size of space the gas furnace is designed to work with. This is one of the most important limitations of a gas furnace. If you buy a furnace that is designed to heat 500 cubic feet for a building that has 700 cubic feet of space, that furnace will never be able to heat the air efficiently and will run on long, expensive cycles when it attempts to.