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garage heater

18K views 20 replies 9 participants last post by  stefanP 
#1 ·
I want to do bodywork/paint in winter months. I was thinking about getting 30K BTU propane tank mounted heater and go at it. I have 3 car garage and one bay is set up as a temporary spray booth. Should it work out or is there possible problems?
 
#5 ·
I would go propane for ease of installation. It burns pretty clean ( a lot depends on the supplier) and ease of installation. B vent is the same as hot water heater venting, inexpensive and easy to shoot out the roof. If you went direct vent it would be enclosed and there would be no problems of any contaminants. A heater hanging from the ceiling works well, puts out a LOT of heat in a short time.
 
#6 ·
Kerosene is NOT clean and must not be used in an enclosed space. Vent-free propane heaters can be used indoors (all now have an oxygen depletion sensor anyway) but they DO create a lot of water vapor. Both have exposed flame and will possibly cause an explosion if you are spraying any solvents or paints.
 
#8 ·
matts37chev said:
good point :thumbup:
I kinda feel like all the heaters, if in the same room, should be shut off while spraying
or you may have the kind of flame job you didnt want :pain:

I realize you have to be careful, but I have sprayed with an open flame heater in the same building....and I didn't die :thumbup:

What I did was build a spray booth with heavy mil plastic. It was from floor to roof. I also built a boost exhaust fan that pulled air from the booth out of my roll up door. I am in the country so I got away without a big "green" exhaust system. I installed an A/C filter in the top rear of the spray both with lots of packing tape.

When I painted, I heated the entire shop for a couple of hours so everything including the car was up to temperature. Then I cracked the exterior door outside the booth and kept the heater running. Once I was ready to paint I kicked on the exhaust fan which drew warm air from the rest of the shop into the booth and with the heater on high it was able to help preheat the "fresh air" coming in the cracked entry door.

Now, this will work if the outside temp is not too cold and if you dont have alot to paint at one time. What I was doing was painting in pieces.

It is ******* engineering, but it worked. My heater is a 40,000btu forced air propane heater and it does pretty well in a 1200 ft shop.
 
#9 ·
If you have a vented propane heater you shouldn't have moisture problems. I believe where moisture problems come up is when things cool there will be a moisture left behind as the metal cools. Getting everything toasty warm will help, as everything warms in the shop, tools, cars, walls, etc., the heat will stick around longer. This may take heating the shop for a few hours before you start working. I would get the shop warm, 72-75 degrees, shut the heater off, do my painting, wait until the paint is set up fairly well, then turn the heat back on for a few hours. I don't much like vent free heating, moisture, gasses, have to go somewhere. 99% efficiency is just that, but there are not a lot of btu's involved. A ceiling mounted heater would be my first choice, run copper for propane, a thermostat, vent through the roof, a fairly simple job to do. If you were in a colder state this might not work too well but you don't get terribly cold in Wa. Turbo has the right idea for his set-up.
 
#10 ·
Oh yeah, one more thing.

If you do exhaust and fresh air venting, which is a must for painting you need to oversize your heater a bunch or your shop will be cold in about 3 minutes after you kick on the fan. Most heaters are rated in BTU's, and a ton of heat is 12000 BTU's. To heat you can do a decent job with 4-800 ft/ton depending on insulation and ceiling height. If you vent it heavily the amount of heat needed to hold temperature even a little while goes up dramatically. I would try to get 40-60K btu heater at least if you want to keep the shop warm for more than a few minutes if it is very cold outside at all. My 40K unit will heat my 1200ft shop in a half hour or so if outside temp is 20-30 degrees. Then I can idle it back to low and hold temperature....or keep it throttled up if vented or a door is open.
 
#12 ·
TurboS10 said:
I realize you have to be careful, but I have sprayed with an open flame heater in the same building....and I didn't die :thumbup:

yet :pain:



ogre said:
buy a used home heater off of craigslist. i have a 100 gal propane tank outside, fill it once a yr

this a good and cheap, way to go :thumbup:

I have an electric forced air furnace that came out of a newer home that was converted to a heatpump, in my garage
i just plug it into my welder extension cord when I want to use it :thumbup:
 
#13 · (Edited)
matts37chev said:
yet :pain:




this a good and cheap, way to go :thumbup:

I have an electric forced air furnace that came out of a newer home that was converted to a heatpump, in my garage
i just plug it into my welder extension cord when I want to use it :thumbup:
Actually....

The furnace on your heater there has an open flame with a tiny little combustion fan. If it resides in the shop in question it is no different than my propane heater....maybe worse. It has a fixed flame with little air circulation around the flame itself making it more of a bomb situation. This is because the air in the room is not very turbulent so the fumes can creep toward the open flame and become very concentrated until the combustion fan picks them up at which point they can be very strong. It is like the whole gas leak with pilot light situation. With a forced air setup the air is circulating rigorously through the combustion chamber so fumes would be more likely to burn off slowly before they were concentrated enough to explode.

Oh, and that electric heater element will create combustion as well.

I still think if you isolate the paint booth from the heater location and keep the exhaust fan running you are perfectly safe.
 
#14 ·
TurboS10 said:
Actually....

The furnace on your heater there has an open flame with a tiny little combustion fan. If it resides in the shop in question it is no different than my propane heater....maybe worse. It has a fixed flame with little air circulation around the flame itself making it more of a bomb situation. This is because the air in the room is not very turbulent so the fumes can creep toward the open flame and become very concentrated until the combustion fan picks them up at which point they can be very strong. It is like the whole gas leak with pilot light situation. With a forced air setup the air is circulating rigorously through the combustion chamber so fumes would be more likely to burn off slowly before they were concentrated enough to explode.

Oh, and that electric heater element will create combustion as well.

I still think if you isolate the paint booth from the heater location and keep the exhaust fan running you are perfectly safe.
That;s that I'm planning on doing. I think I'll go with 70K BTU kerosene heater
 
#15 ·
TurboS10 said:
Actually....

The furnace on your heater there has an open flame with a tiny little combustion fan. If it resides in the shop in question it is no different than my propane heater....maybe worse. It has a fixed flame with little air circulation around the flame itself making it more of a bomb situation. This is because the air in the room is not very turbulent so the fumes can creep toward the open flame and become very concentrated until the combustion fan picks them up at which point they can be very strong. It is like the whole gas leak with pilot light situation. With a forced air setup the air is circulating rigorously through the combustion chamber so fumes would be more likely to burn off slowly before they were concentrated enough to explode.

Oh, and that electric heater element will create combustion as well.

I still think if you isolate the paint booth from the heater location and keep the exhaust fan running you are perfectly safe.
my answer to that is
matts37chev said:
good point :thumbup:
I kinda feel like all the heaters, if in the same room, should be shut off while spraying
or you may have the kind of flame job you didnt want :pain:
I have been in the gasoline /tanker transport industry as a driver or tanker mechanic most of my adult working life

I have had it beat into my brain in training classes :nono:

I am very aware of possible ignition sources and vapor type fuel pathways

so sometimes i can get a little weird about this stuff :boxing:

so I am sorry if I get over excited :spank:
 
#16 ·
TurboS10 said:
"I realize you have to be careful, but I have sprayed with an open flame heater in the same building....and I didn't die"

Give it a chance, you may yet. I didn't fall off a 12 foot roof for the first 75 years of my life.......but I did 28 days ago and it hurt. I am slowly recovering, thank you. As for the unvented propane heater, turn it off when spraying. This from an old natural gas co. employee and retired Firefighter who has seen may unnecessary injuries and deaths. Even my "accident" could have been avoided.
 
#17 ·
I installed a used f/a natural gas furnace I purchased from A&M heating . I added a small furnace room (4'x4') on the exterior of the garage.

(if you do not have NG, then convert the burner to LP and set up a 100 gallon tank.)

It is installed as a 100% loss system, there is no cold air return from the heated area. I did it this way so I could keep positive pressure in the room. I exhaust the air through a filtered man door opening.

I have considered putting a return duct between the furnace room and the garage for just heating in cold weather. I would put a sealed door on this opening so I could close it for painting.

$100 for the furnace
A friend in the industry supplied the duct work.
$200 for the furnace room materials.







I hope this might give someone an idea how to heat their garage/shop/spray booth cheaply. (well as cheap as energy costs these days :( )
 
#18 ·
Old Fool said:
I added a small furnace room (4'x4') on the exterior of the garage.

It is installed as a 100% loss system, there is no cold air return from the heated area. I did it this way so I could keep positive pressure in the room. I exhaust the air through a filtered man door opening.

I have considered putting a return duct between the furnace room and the garage for just heating in cold weather. I would put a sealed door on this opening so I could close it for painting.

I hope this might give someone an idea how to heat their garage/shop/spray booth cheaply. (well as cheap as energy costs these days :( )
this sounds like a nice set up :thumbup:
Old Fool said:
I have considered putting a return duct between the furnace room and the garage for just heating in cold weather. I would put a sealed door on this opening so I could close it for painting
sounds like a very good $$$ saving plan :thumbup:
 
#19 ·
Old Fool said:
I installed a used f/a natural gas furnace I purchased from A&M heating . I added a small furnace room (4'x4') on the exterior of the garage.

(if you do not have NG, then convert the burner to LP and set up a 100 gallon tank.)

It is installed as a 100% loss system, there is no cold air return from the heated area. I did it this way so I could keep positive pressure in the room. I exhaust the air through a filtered man door opening.

I have considered putting a return duct between the furnace room and the garage for just heating in cold weather. I would put a sealed door on this opening so I could close it for painting.
Best one yet! :thumbup: I like keeping furnaces and compressors away from my work area when possible.
 
#20 ·
I should have mentioned I installed this setup for painting.
The rest of the time the garage is heated by a 40k btu NG unit heater with thermostat set at 45f unless I am working out there.

The unit heater can be seen in the photo with the duct work, it is to the right side of the duct work.
 
#21 ·
Garage heating

I borrowed a 13'000 btu oil fired/hot air furnace from a building that was being torn down :D .That was 12yrs ago :thumbup: .But anyway this is what I use.It's nice because when it's cold(northeast) I set the thermostat for 50 degree's' ;) .Garage stays nice and warm.I put iol in the tank when I fill my house.Nicest thing is when I want to work on a project I just turn up the thermostat to 60degree's and with in 10min I in a tee shirt.My garage is 24'x30' with 10' ceilings.6" walls insulated and sheeted.So it also depends how good you insulation is.Thats what I have to offer. Stay warm,
stefanP
 
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