Garage furnace question

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pauls340

pauls340

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I have a Ducane 50K btu furnace I am putting in my garage attic. Garage is 600 sq ft . It says it is also a horizontal unit which I assume means I can suspend it laying on its side. The unit was in a house so there is a 14"x25" hole for the cold air return. I am thinking of getting one of those 4" thick disposable filters and strap it over the hole. Anyone have any tips...if they have done this? Thanks
 
You should be good to go, our you can buy a return filter vent 14"x25" or bigger that holds a filter and just screw it to it.
put a turn down on the supply side to create some back pressure and send it down to the floor
 
I had a local heating contractor install a new furnace in my shop. He chose to install it suspended from the ceiling/roof on it's side. Works fine.
 
pauls340 said:
I have a Ducane 50K btu furnace I am putting in my garage attic. Garage is 600 sq ft . It says it is also a horizontal unit which I assume means I can suspend it laying on its side. The unit was in a house so there is a 14"x25" hole for the cold air return. I am thinking of getting one of those 4" thick disposable filters and strap it over the hole. Anyone have any tips...if they have done this? Thanks
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I would run the return air duct through the ceiling down to within a couple feet of the floor and install the filter holder. Duct the outlets through ceiling diffusers. Check with a furnace guy to make sure you have enough outlets off of your plenum with adjustable dampers. The dampers can be adjusted and locked in place for the correct differential pressure through the furnace.
 
Skybolt, here's a pic of the furnace...horizontal and suspended from the ceiling. The cold air hole is on the top. I got a 16 x 25x 2" filter that I am going to set over the hole. Since I will only be using in the Winter, do i have to run ductwork down to the work area. This furnace is in the storage area above the 9' ceiling. I appreciate your help.

Garage Furnace 1.jpg
 
pauls340 said:
Since I will only be using in the Winter, do i have to run ductwork down to the work area. This furnace is in the storage area above the 9' ceiling. I appreciate your help.
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Yes, you should. It's not really that hard, but will cost a few bucks for ducting. By leaving it up in the "attic", you are not really moving the air in your garage. You are just pushing around warm air. By running the cold air down to the floor, you are sucking the cold air up to the furnace, thereby forcing the hot air down from the ceiling. Otherwise, your ceiling will be really warm, but the floor, where you are working on your car, will never really warm up.

And who ran your gas line? There should be a shut-off valve and a drip leg close to the unit. Is it just past the edge of the pic?
 
Paul, On that type of system fix you up a cold air return coming off of the floor(that's where the cold air lays), and run it up to the furnace. Face the discharge toward the floor and you'll be good to go. Mine is a Hardy wood burner that heats the house and the shop. It sets outside and heats the water that runs to a radiator at both locations. The fans in the plentium blow through the radiators, picking up the heat and blowing it down into the shop. I also have a set of window fans blowing the heat down off the cieling, sorta like a heat recovery thing. A lot of hot air hangs high at the cieling so get you some of those cheap box fans and let em help ya out.
Small Block
 
The other issue with the furnace getting it's fresh air from the attic and not the garage is it will be working it's but off trying to constantly heat the outside air, especially when it is below freezing. The cold air in the garage is going to be a lot warmer than the outside air in the attic area so the furnace will be more efficient and run less. It may also be a good idea to insulate the rafters in your attic to keep the furnace from drastic temp changes between cycles, especially if it was designed for indoor use where the temp only changes 10-15 degrees at a time.
 
Just like everyone here says, you need to duct the cold air return to the furnace from inside the garage.
 
So i'm going to fab a filter box to cover the rectangle on top (in pic), then run a 6" oval duct down to 12" off the floor with a 90 degree kickout. This should suck cold air off the floor and return it up through the ceiling to the furnace....correct (?)
 
pauls340 said:
So i'm going to fab a filter box to cover the rectangle on top (in pic), then run a 6" oval duct down to 12" off the floor with a 90 degree kickout. This should suck cold air off the floor and return it up through the ceiling to the furnace....correct (?)
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I don't think 6" diameter will be enough.
 
pauls340 said:
So i'm going to fab a filter box to cover the rectangle on top (in pic), then run a 6" oval duct down to 12" off the floor with a 90 degree kickout. This should suck cold air off the floor and return it up through the ceiling to the furnace....correct (?)
Click to expand...

No. Won't be enough. Check with a furnace guy. You have to supply enough air to the furnace, what ever it is rated at and also have enough discharge air for the furnace to transfer the heat from the furnace. Duct work does not cost that much. Talk with a furnace installer.
 
So my furnace guy tells me I need to add an 8" to the two 6" heat ducts AND I should have a cold air return 12 x 4 to go with one on the 9' ceiling...sure fu*^^*&kin glad I got a good deal on the furnace. There goes most of my storage area.
 
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