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i wanna know about king portable garage heaters? does anyone have installed garage heater in 2 car garage. so tell me about what wattage are enough for heating 24 x 12 area?
 

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will you be parking wet or snow covered cars? Once the heat is turned off all of that moisture will form ice/frost on the exterior walls or bottom of roof deck.

Bud
 

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A 2 car garage is about 24x24. A single car garage is about 12x24. 1500w (5,000 BTU) is the maximum any 120v portable heater can deliver.

Nobody likes rules of thumb but in a typical insulated residential environment, you need approximately one ton (12,000BTU) of heating per 400-800sq ft.

In an uninsulated 2 car garage (approx 600sq ft, assuming you really have a 2 car garage), I doubt a single 1500w heater is going to work.
 

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One 1500 watt heater will make your electric meter spin like a drill , two will make it spin like a router and three will make it spin so fast you can split atoms :biggrin2: Without knowing where you live , the insulation level of the space and what your expectations are we are just spinning our wheels .
 

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Nobody likes rules of thumb but in a typical insulated residential environment, you need approximately one ton (12,000BTU) of heating per 400-800sq ft.
So you would put the same amount of heating regardless of whether a house is a long, narrow rectangle or a square?

If you're going to use a rule a thumb, it should at least be based on exterior surface area, not floor area.
 
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Rule Of Thumb:
"A broadly accurate guide or principle, based on experience or practice rather than theory"
Absolutely nothing wrong with sktn77a's answer. It supplies a starting point rather than an exact calculation.
 

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But the problem is there is no such rule of thumb.
And hvac is based on theory. Not someone’s opinion, or “experience”.
Sizing is NOT based on square footage.
 

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The calculation for heat loss on a garage are so iffy due to the wide range of variables that you are better off calling the manufacturer of the unit you are considering buying and see what sizes they offer. Many times you can get the next larger size than you think you need for just a little more cost. With electric heat, there is very little efficiency lost by having one too big.

Example: With an uninsulated 2-car garage, you obviously won't be able to use the smallest unit available, which is usually a 5KW @ 240 volts. The next larger size is 7.5 KW but it costs nearly as much as the 10 KW, so there you go, get the 10KW one. That 10KW unit will require a 50 amp 240 volt circuit. It'll cost roughly $1/hr +- to run depending on what your PoCo charges for juice.

Insulate that garage and especially the door/doors, and you can get by with the small unit and cut the electric cost in half.

All of the above assumes it gets down in the teens at times where you live. If it gets below zero there, you will definitely need to insulate.

I'm not saying you can't or shouldn't calculate the heat loss but if the increments for selecting a proper unit aren't any closer than I usually see, you don't really need an exact loss number. Most people decide to forget it when they find out what it costs.
 

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TIP: I forgot to mention that if you don't have a ceiling lid in that garage, you will want to check to see if you have the normal roof ridge vent, you will want to tape it closed or plug it by some other means to keep the heat from escaping. Also you need to stop the soffit income air. Like I said, lots of variables.
 

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Check this one out, it has pretty good reports and the price is better than most and you may be able to get it locally.
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10 KW Garage Heater
 

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i wanna know about king portable garage heaters? does anyone have installed garage heater in 2 car garage. so tell me about what wattage are enough for heating 24 x 12 area?
I have a 14 X 24 portable building that I use as a shop.
It has R-13 insulation in the walls and ceiling. The shop sits on blocks so the floor is not insulated. I use a Farenheat FUH54 heater.
It will heat the shop from 32° to 65° in about an hour.
I do not leave it on since I do not work in the shop everyday. I have added a small fan on the ceiling kitty-corner from the heater to circulate the heat.
I am satisfied with the results of this heater.
Choosing this heater was based on square footage. It appears to be an accurate calculation.
That being said....insulation, number of windows, ceiling height and whether the floor is insulated, wood or concrete will all factor into the efficiency of the heater you choose. I have used many portable heaters over the years, from electric to propane to kerosene. I used a salamander type heater, 100,000 BTU back in Illinois in an uninsulated garage. It kept it warm enough to work in.....until the fumes made you leave.:vs_laugh:
 

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Sizing a heater for a garage which is kept cold most of the time is different from a living space -> need surplus capacity to raise the temp fast and consistent heat is not a priority.

For a living space, oversizing is detrimental when it comes to comfort and for everything but resistance heat, efficiency too.

Now, heat loss is simply not proportional to square footage. The ratio of exposed surface area to sq footage drops as sq ft is increased.

A 2400 sq ft house doesn't need close to double the heat of a 1200 in the same climate. More like 50%, construction and ceiling height being similar.
Yet with a stupid rule of thumb like 40 btu per sq ft, a decent 2400 sq ft house in the northeast gets a 100k furnace instead of a 60 to 70.

Rules of thumb seem to work okay because they almost always result in gross oversizing and people don't complain unless there's insufficient heat.

It's not very hard to do accurate load calculations especially with software. Best to learn how.
 

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I used a salamander type heater, 100,000 BTU back in Illinois in an uninsulated garage. It kept it warm enough to work in.....until the fumes made you leave.:vs_laugh:
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Salamander (vertical style)... been there, done that! Choked, all the while wondering when it was going to explode and kill us all! :vs_laugh:
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