Air Intake Options For Gas Furnace

Old 03-31-10, 07:19 AM
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Air Intake Options For Gas Furnace


I have a 1 year old Goodman gas fired furnace in the basement. Currently the air intake draws from the basement. I have been given conflicting advice from 3 home heating service firms. 2 say to pipe the intake outside to improve efficiency. 1 says to leave it alone since the furnace will need to work harder in order to warm the intake air in winter (I live in MA).

Which do you feel is the better course? Thanks
Old 03-31-10, 08:20 AM
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I'm supposing that the furnace is designed to have an option to use outside combustion air. If so, you can expect to gain 1-2% in efficiency by using outside combustion air rather than heated room air.

I'm supposing that the room where the furnace is located is heated.
Old 03-31-10, 04:17 PM
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Indoor or outdoor

I always prefer to use two pipes. When you draw combustion air from inside it creates a negative pressure in the house which is eventually made up by outdoor air anyway. The big difference is with a combustion intake piped directly to the furnace, that outdoor air is drawn only to the furnace & not into the living space.

One important thing to remember in running an intake air pipe: The intake must be in the same "atmospheric zone" as is the exhaust. In plain English this means the intake must go thru the same was as does the exhaust or if the exhaust goes out the roof, so must the intake pipe. I actually prefer a concentric vent & intake.

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