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Bearston · Nov 4, 2008, 03:59 PM

Hi, I rented a house that has an outer building (stand alone) which had the furnace and exhaust vent stolen (some people!). I have purchased a GMC gas furnace and it has a blower to force the exhaust out. What is the best way to get this combusted gas out of the building, with a B Vent or should a Z vent be used. Thanks for any help!

hvac1000 · Nov 4, 2008, 04:07 PM

What efficiency is the furnace?

80+ can use B vent

90+ can use plastic pipe.

Some 80+ can be side wall vented. Follow the directions that came with the unit.

Bearston · Nov 4, 2008, 04:14 PM

Efficiency is 84%. I would like to sidewall vent like at my gal's home. She has a metal z vent and about the same efficiency. To sidewall vent is B acceplable or is it better to go with the Z? Thanks again for the insight.

mygirlsdad77 · Nov 4, 2008, 04:43 PM

need to follow manufacturers instruction, as hvac stated.

Another question for hvac, what is z vent?

hvac1000 · Nov 4, 2008, 04:46 PM

Z-Flex Chimney Liners and Venting Systems - Nova Flex

here is Z vent. It is a liner material.

mygirlsdad77 · Nov 4, 2008, 05:01 PM

Ok, have used nova flex, just never was told that it was z vent. Thanks again for a learning experience.

Bearston, As far as I know, "Z Vent" is used exclusively as a chimney liner for 80 percent gas fired units. I don't think you can use this for side vent applications. For your project, I would recommend just running a b vent up and out through the roof of the building. You can use single wall vent pipe off the top of the furnace, up to as close as seven inches from combustilble materials, then you must convert to double wall(bvent) when you go through the ceiling and the rest of the way up though attic and roof. Let us know what you decide, and hope all works out well for you.