If you do HVAC I need your opinion

[EVIL AWD]

I'm in the market for a new garage heater and I have made up my mind that I want to go with a natural gas forced air unit mounted on the ceiling. But I have a question maybe some of you can give me your opinions on. Typically the exhaust is vented up through the roof. However, this unit comes with a power exhaust which allows horizontal venting. What I would like to do though and I don't see why it would cause a problem, but maybe some of you know better. I want to run the exhaust venting downward from the unit on the ceiling to the floor and then out the side of the garage using an existing hole where a dryer was once vented years ago before I bought the house. Does anyone think this will pose a problem?

[indyzmike]

I don't know, but some of the code rules seem wierd. A nat. gas pool heater and a wood burner must be vented to a foot above the tallest part of the roof. Then they install a furnace, and vent it out the side of the house. What gives?

[EVIL AWD]

Yeah, I'm not all that concerned with it being up to code. I'm more concerned about the way I would like to vent the exhaust piping posing an operational problem. If I were to ever sell the house I would be removing the heater anyway.

[Lash]

You're talking about a unit heater...right?
Is it a fan powered vent (has a small fan pushing the fumes out)?
Typically...you don't really want to vent downward. Gas naturally wants to go up. You dont want that sh!t coming back into your garage.

I'd check with local codes first. Plus there are different restricts for the length of the vent and the amout of 90* elbows you can use. Each unit is different.

Here is a typical installation manual..
Venting starts on page 5..

http://www.northerntool.com/downloads/manuals/172644.pdf

[EVIL AWD]

Lash,

Thats the exact unit I was going to get from Northern Tool. I guess I might have to come up with a different plan for the exhaust venting. It just would have been nice to use the existing hole if I could. Oh well, I'll figure something out. Thanks.

[Lash]

If you're going through a wood wall (like out the wall)...you need to use B-venting too....not just regular single wall duct. It'll get really hot and start your house on fire.

Is your garage siding or brick? It's not that hard to cut (or core) a hole and vent it.

[awsomeears]

Venting downward is a no no.

You should use B-vent as lash mentioned if you decied to go threw your roof.

How much are you looking to spend on a unit ?

Is this garage insulated and drywalled or just all joist and 2 by 4's ?

I could get you a furnace for a few bucks, it will be used and prolly from the late 80's early 90's

[EVIL AWD]

If you're going through a wood wall (like out the wall)...you need to use B-venting too....not just regular single wall duct. It'll get really hot and start your house on fire.

Is your garage siding or brick? It's not that hard to cut (or core) a hole and vent it.

Oh yeah, I would be using b-venting no matter what. I would be cutting through lannon stone if I just went horizontal with it. I could go through the roof too, that wouldn't be the biggest deal. Like I said before I was just wondering if I could use an existing hole to make things a little quicker and easier. Thanks guys.