Garage Heating

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i have a 24 x 32 and use (1 ) 65,000 btu hotdawg, it cost just under 500.00, installed it my self and had a plumber friend of my hook it and pipe it out for a couple c notes, works very well! propane is spendy -- cold here too! i heat it all winter 30 degrees when im not in there, takes 5-8 min. to bring it up to 55 degrees,
 
KP said:
How many of these would be needed for a 24' x 32' garage?
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I have one of the 45k btu heaters in my 24x24 building, R13 in walls, ceiling is R38 for first 6 feet on each side and R19 for the 12 feet in the middle (Has loft). it's more than big enough. If your insulation is the same or better than mine, I think one 45k would do it, but one 75k unit will heat it up from dead cold faster. For reference the furnace in my house is 65k btu input.
 
snoreen40 said:
i have a 24 x 32 and use (1 ) 65,000 btu hotdawg, it cost just under 500.00, installed it my self and had a plumber friend of my hook it and pipe it out for a couple c notes, works very well! propane is spendy -- cold here too! i heat it all winter 30 degrees when im not in there, takes 5-8 min. to bring it up to 55 degrees,
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Where did you get your unit and do you have a photo of it?
 
Now for reference BTU rating (for example 45,000 BTU) is heater input per hour.
Heat output is btu input x efficiency 45,000 x 80% = 36,000 btu,for a non-condensing furnace like these. Condensing units can be upwards of 98% efficient.

One gallon of propane contains 91,000 BTU.

20# cylinder of propane holds 4.7 gallons or 427,700 btu or 9.5 hours @ 45,000 btu input.

Vaporization Rate: as you see from this link http://www.generatorjoe.net/html/PropaneNGUse.html (scroll down to vaporization rate of cylinders) a 20# cylinder will not run a 45,000 btu heater. It takes two 20# cylinders at room temp in parallel to supply a 45k heater, at 10 deg it takes five.
 
100,000 btu of LPG burnt produces 1.5 gallons of water. So one of those big vent free space heaters could easily put 5 to 10 gallons per day into your garage and it's insulation.
 
jeryst said:
Hold on pouring the floor, and install PEX tubing before you pour. Simple to install, cheap to heat, and its great. The floor is always warm, and once you heat it up, it is a huge thermal mass, so it doesnt take much to keep it going.

First, lay down gravel so that the ground is as level as possible.
Lay down 2" Styrofoam insulation.
Put down reinforcement wire.
Attach the PEX tubing to the wire using plastic cable ties. (There is a certain pattern for how you lay it down)
Attach the PEX tubing to a manifold and pressure test.
Pour the floor.
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Great suggestion!
I talked to a couple of heating contractors that do a lot of Radiant heat. They recommend installing the heat tubes in the concrete whether you plan on hooking them up right away or not. A garage can be heated with a water heater and is always comfortable. I have a few customers shops heated this way and they love it and it heats cheap. toolmanmike
 
LOL.....heating workshops.....here, it's trying to cool them down......LOL
 
1MeanA said:
+1 on the garagejournal site. I run a HotDawg heater too. You only need one and they come in various sizes. IIRC mine is a 30,000 btu for a 24x26 with 11 foot ceilings and R20/40 insulation (it gets cold here). The majority of the cost (over 50%) was running the gas line to the garage! I know some have crunched the numbers and used a propane tank installed outside instead of getting a gas line installed. There is a thread on GJ on this.

ps without a vent stack the humidity level skyrockets in the garage. I found this out when using a 55,000 btu propane heater to heat the garage while I finished the walls.
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Correction, I may have used the 45000 btu unit. Its been awhile.
Here is a link:

http://www.modine.com/v2portal/page.../building_HVAC/market_level_3_content_013.htm
 
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