Garage Heat

[RD911T]

I need a little wisdom from the collective. I have an attached 3 car garage that is insulated with two good sized window on the west wall. There is a bedroom in the house proper above the garage, so I have heated space on one wall and above. Space is approximately 30x24 ft.

I want some heat so I can work on my car this winter comfortably. When the weather gets below freezing around here (in Missouri south of St. Louis about 100 miles) the garage will hover around 50 F. If it get down in the low teens the garage will dip into the high 40's F.

I had a 220v plug wired and bought a 4kw electric heater from Menard's. I thought I would just run it for a few hours before I started working on the car to get the temp up. Last night I ran into a guy and we had a discussion about the space and heating and he suggested it might be pretty cheap to run the heat all the time with his theory being that once the concrete slab was warm, it would hold the heat and would require minimal use of the heater to keep the space warm even with the doors going up and down, cars in and out, etc.

Electricity is $0.0753/kwh from Ameren MO locally. So at full blast the heater will cost $0.301 per hour to run. I ran it last night for 12 hours and the temp got up to 69 F according to the outside temp sensor on the vehicle in the middle spot and 60 F according to the outside temp sensor on the vehicle in the farthest spot from the heater. In the past with no heat both temp sensors would read within 1 degree of each other. So call it 65 F overall in the garage.

I'm wondering about the wisdom of running it all the time, or at least most of the time when I'm planning on being out there a lot?

[T77911S]

electric heat would be my last option.

how do you heat your house?

you might look into gas. if oyu dont have a gas line you could put a propane outside and put a propane heater inside.

[mnez]

Just run it when you need it. With jeans, T-shirt, and sweatshirt you will be fine at 50*, likely too hot at 65*. Put on some coveralls and you will be fine at 40*

[brads911sc]

Electric heat would be my last option as well.

Heat Sink, or Cold sink in this case, does require more initial energy to overcome than maintaining a constant temp. The question on whether it is cheaper depends on the frequency. If you were using your garage 2x a month, I would think that maintaining the temp 24/7 would be more costly than getting the garage up to temp 2x a month. if you are using the garage 3x a week, then it very well might be cheaper just to set the termostat and maintain it.

[bazar01]

50's is just perfect for wrenching inside the garage on a pair of blue jeans and long sleeve cotton shirt. 40's might be a little cold but with coveralls, it will be just fine. Electric heating is not very efficient. Get a vented propane heater.

For garage heating ideas, this is a good resource.
Heating and A/C - The Garage Journal Board

[RD911T]

Venting would be a difficult option the way my house is set up, plus I would have to overcome the spouse factor which is not insignificant.

At this point I have less than $200 in the electric heat setup and I think it will work fine. More than anything, writing this post helped me organize my thoughts. I think this will work fine, but it doesn't make much sense to run it a lot when I'm not working on the car. Thanks for listening!

[HelmetHead]

I have seen lots of local body shops utilize infrared heat as it doesn't heat the air but keeps the shop comfortable. Just a thought?

Residential Garage Heaters | Series GR - Infrared Garage Heater, Superior Radiant Products Ltd., Energy Efficient Infrared Heating Solutions

[Rot 911]

Tom, hello from Jeff City! For you guys outside Missouri, electrical heat is relatively inexpensive here. But I wouldn't run the heat constantly. You have a good theory, but in my opinion, the ground will suck up the heat faster than the concrete can be warmed up. I would run it in conjunction with a good infared heater while you are in the garage. The two in combination, should make things quite comfortable.

[wayner]

This might not be your answer but for others reading this thread and planning new grages it may be useful

1) Heat source?
When I build my dream garage I plan to heat the floor slab, not the air. If you have ever worked in a heated slab garage, you'll know that the air doesn't need to be as warm if you are standing on a warm floor, and most of the heat remains down around you longer instead of up around the ceiling. Essentially when you are building you run cooling tubes first and then pour the floor.

2) Constant heat or once in a while?
One factor that will help you decide is "do you plan on parking your daily driver in there?

Where I live they use lots of salt on the roads in the winter. I avoid indoor parking when I go down town. My cars rust a lot faster it seems when I park in heated spaces that allow the snow and salt to go to work when things melt/freeze/melt every day.

I would want to heat it every day constantly, but then wouldn't want to park in it...

[gint]

How warm does it have to be? My garage temps are similar to yours. 1135 sq. ft floor space. When it's 45-ish in there it is a little chilly. I break out the propane bottle top radiant heater and I can usually bring the temp up to 50 in a couple of hours. That's more than enough for me. Especially if I'm doing anything mildly physical.

[Porchcar guy]

Another thought would be to lay down interlocking mats that would keep the heat sink at a minimum. I did this in my garage and without the heat on, the floor is quite comfortable. Mine is a 2 car garage but leaves an area to work on one car in the center. I left a 4' wide by 16' section that is vinyl tile so I can use jack stands without crushing the mat area.

[wildcat077]

My garage is 24x32 with a 10ft ceiling and is attached to the house.I don't heat it in the Winter unless i need to work in there,which is often the case ...
I have two 4800W construction heaters suspended from the ceiling at the garage door end along with a 60 inch centrally located ceiling fan that circulates the warm air around.

I've been in my house for 22 years and this has met my heating needs perfectly !
I never park any of the cars in the garage except for the Porsche ...

Cheers !
Phil

[matt f]

My garage is 1200 sq. ft., attached and insulated. I use 2 electric ceiling fans that have a heating element. They were purchased at Lowe's. I turn them on 1/2 hr. before I need to be out in the garage. 55 degrees is perfect for me.

Good luck.

Matt

[GaryR]

I installed a Frigidaire FRA25ESU2 25,000 BTU Cool/16,000 BTU Heat - Heavy Duty Window Air Conditioner with Heat this spring knowing that for heat I would have to supplement it with something (these units are great but can not be used for primary heat). As I didn't want to deal with running a propane line and the associated venting necessary I just went with a fan forced 230V electric unit. I had my electrician make me a custom extension cord that plugs into my welder outlet so I can move/direct it to the area i'm working in. I like it to be about 55F when i'm working so between this and the wall unit I will be fine. The AC is the bomb in the summer, 25K BTU keeps it 65F in there even on 100F days.

[zotman72]

I am old skul, with a '80s Kerosene heater in my garage. I also freeze my a** for the first couple of hours in Colorado winters before things warm up to 60 degrees. YMMV

[frosty2]

Hi Tom your electric heater should do fine for what you want as with the size
of your garage and having the ceiling and one wall already heated you heating
load should be between 12,000 and 15,000 BTU (3.5 to 4.5 KW).
Make sure you have a fan to move the air across the room.
If you want to maintain heat all the time I would suggest keeping it at approx
50 to 55deg F and that way it will not come on that much because of the heated
wall and ceiling and then just turn it to 60deg when you want to work out there.
Another alternative is a garage propane unit heater.
There is a nice one on the market by Modine called the Hot Dawg, its small in size
and hangs from the ceiling.
I think the smallest is 30,000 btu but again maintain 55deg and turn up when
you require heat and it will heat up quickley.
Thanks
Mike

[Craig_D]

Here's what I'm using currently, and it's been cold in Colorado over the past two weeks (garage temps around freezing when I start working). Cost me $45 at Home Depot.

[blucille]

careful of the fumes, boys....I am leery of anything that burns something (propane, kerosene) unless it is vented to the outside. I quickly get a headache if I'm around any unvented heaters.

I've got a mostly uninsulated 1000 sq ft barn, two stories....I bought a modine hot dawg 75,000 BTU natural gas heater....in the dead of winter, I can walk out there, crank the thing up and be comfortable in 15 minutes, I can bring the temp from well below freezing to 65 degrees quickly. Of course, I had to run natural gas out to the barn, and did so, plus water and electricity when I was doing some other work, shortly after I bought this place 10 years ago.

[Lukesportsman]

In support of Soneet43, I once (it was very cold and I was fairly young) fired up a propane and kerosene heater in the same garage. I don't know the chemistry behind it, but it drove us out of the garage in minutes. I WARN about mixing non vented combustion. Plus the fear of aerosol fumes in such an environment.

[72T]

+1 on the propane tank heater. I'm using the same setup. It's cheap, movable to where I'm at without any trouble, and can be put back on the grill when warm weather returns.