Safe Ways to Vent a High Efficiency Furnace

New Ducts

• If you buy a new high efficiency furnace, you will probably need to create new ducts for venting. This means that no matter where you place the furnace -- whether in the attic, basement or garage -- you will need easy access to outdoor air. A garage or basement furnace may be able to go through a wall, while an attic version can go directly through a ceiling.

Chimney Liners

• If you have an old chimney that you would prefer to vent through, inspect the chimney to see how it is lined. High efficiency furnaces tend to produce a caustic gas that can eat through most traditional chimney liners. If you are willing to install a new lining that can resist the acidic exhaust, you can take advantage of this old chimney, but do not simply use an available vent without checking it first.

Direct Venting

• Direct venting refers to a system in which the furnace is vented using a two-pipe system that goes directly from the furnace to the outside air, typically without using any existing duct work. One pipe brings in air necessary for combustion, while the other pipe carries away the exhaust safely, with corrosion protection and the other features necessary to deal with the furnace gas.

Single Pipe Venting

• Single pipe venting refers to a venting process whereby both exhaust and supply air are taken care of with a single pipe. This type of pipe vent must be more than four feet away from doors and windows, but it often requires less work to install. It is actually made from an outer pipe and an inner pipe so that exhaust and supply air can both be channeled separately.