Garage heating

Hello, Y'all!

I’ve seen several articles on heating a garage here, but I don’t see any that address my needs exactly. I build model wooden ships so It’s vital the wood glue cures.

My garage is 4000 Cubic Feet and well insulated. Even the garage door is insulated with Foamular. I asked google and she said I need 8,000 BTU’s, or 2500 watts.

Of course, the one I let think wears the pants in the family refuses to park her car outside, so she insists on opening the door twice a day.

Anyway, I live in central Ca., but don’t let anyone fool you. It’s currently 53 degrees at 3:00 pm. and I’ve seen it as low as 27 degrees at 4:00 am. The wife leaves around 5:00 am. and returns around 3:30 pm. Of course, her car provides plenty of heat for about an hour when she gets home.

My main priority is a smart heater wherein I can program it like a house thermostat. I’ve read that I can put one “in line,” but if a heater falls within my needs, I see no reason to create more work.

I have plenty of space, so I don’t really think I need a wall or ceiling mount.

Lastly, I have both 120 and 240 Volts available. Google said I won’t really see a difference in my utility bill.

Thoughts anyone?

In reply to PaulyWalnuts :

How much do you want to Grassroots and how much for a plug and play?  Does it get to hot in the summer?

Double or triple check your BTU requirements, there are any number of heat loss calculators available online but they don't always agree with each other.  2500 watts seems low to me but then again I'm in Minnesota.

As an experiment, before making any permanent installation you could get a couple small plug in portable electric space heaters to see if they provide enough heat to maintain temps - they're typically 1500 watts and are cheap (I see them all the time at garage sales for a few bucks, or even sitting on the side of the road for free.)  You will need two separate 120vac circuits to do this, since two of them on a single 15 or 20 amp breaker will overload the circuit.  

Generally, natural gas heat will be cheaper to operate than electric heat, but I don't think you'll be able to find a gas heater that small.  If your intent is to only use the heater occasionally and not 24/7, an electric heater won't necessarily add all that much to your monthly bill - look at the bill to see how much you pay per kilowatt-hour, and then you can figure out costs with some simple math.

Yes, every time the garage door is opened it will cool down inside, but as long as she closes it promptly after pulling the car out the temps should recover fairly quickly.

After googlfying how big a 4000 sq ft garage is.... 

This is what I would use. Maybe two just in case.

https://www.globalindustrial.com/p/natural-gas-infrared-heater-092210ngs-straight-configuration-10-l-40000-btu?infoParam.campaignId=T9F&gad_source=1&gclid=EAIaIQobChMIzMDVmcaQhAMVIHNHAR3yZAhrEAkYBCABEgJ5dPD_BwE

These heaters do not just heat the air they heat objects. They make everything warm.

4000 cubic feet, as in 20'x24'x8'?

Or

4000 square feet as in 50'x80'?

I went with Garagedominium. 50x80

Not the one I have, but same concept.

I don't have gas or propane, so went with electric.  Just yesterday it took my 2 car garage from 46 degrees to 65 in about 10 minutes. I did have to pay for a professional install due to the current demands but it's been worth every penny. I only have it on when I work out there so the impact to the electric bill isn't terrible. If you had to run it constantly it may be more painful. Mounted up at the ceiling so it's not in the way. Very happy with it.

Our garage is about 1.5x the size of yours (31x23 inside, 8.5 foot ceilings, so about 6000 cubic feet).  It's insulated, although the garage doors could use a bit more insulation.  The guy who built it put a 60k BTU furnace in (mounted to the rafters with a pop-up in that part of the ceiling into the attic space).  I think it's probably a little bigger than required, but it's not unreasonably large (especially for warming the garage up a few extra degrees before working on something). 

I don't think 8000 BTU would be nearly enough to keep a 2 car garage warm, especially if the floor isn't insulated and the place isn't totally airtight. 

My shop is 1600sqft with a 12ft ceiling, so pretty big at 19k cuft.  While I'm planning to do a ceiling mount industrial heater at some point, for now I'm using a 5600w, 220v plug in.  It does a pretty good job of warming a work area, but isn't sufficient for the whole shop.  Not very expensive, and should work pretty good in a typical 2 car garage sized area.

Dr Infrared Heater DR-988A

I have a 5k BTU electric heater - "milkhouse heater" we call them -  in my 1.5 car attached garage and it does pretty good even with uninsulated wood door and a glass block window.  It has thermostat connections so you could run it on a Nest if you wanted to but I just turn it on when needed, its not my daily heated garage.  

I have a 60k BTU Natural Gas Modine Hot Dawg in my detached 24x30x12 foot tall garage, all insulated, insulated doors, insulated windows, controlled by a Nest.  Its awesome.

Both varieties impact the utility bill of course

If I just wanted a little heat now and then I would either go electric or use one of those chinese diesel heaters.  

I have the same white box heater in my shop with the same cubic feet.

It does ok but when the temp hit -37c this winter it was running balls-out just to bring the temps up to -10c.

My walls and ceiling are all R24.

I have a wood stove that handles the rest.

How frequently are you there in the garage in cold conditions?

I would go test exactly how well insulated the space is by buying a dirt cheap 1500W space heater, turning it on for a day, and seeing if the place is warm enough. 

That makes 5000 Btu/hr of heat. 

If you're there all the time, your least expensive way to heat the space is a 1/2 ton minisplit. If you're not, then the low first cost of space heaters wins out. 

If you want a fun project, look into "waste oil heater" builds.

Lot of good stuff here, but everyone missed one big question.  Where are the pictures of the model ships?!

Do you care about AC in the summer? A mini split would be pricey but you'd only cry once. One of those 240V electric heaters would be lowest upfront cost. Chinese diesel heaters are quite popular now but I can't recommend them because of the babysitting involved.

The other option is to not heat the whole area if you're only interested in a small chunk of it.  An oil filled space heater with a couple of pieces of foam board insulation can make for an pretty cheap "hut" that would keep your wood warm for not a lot of money...

most thermostats can be configured to drive a micro switch style igniter... for example in my old home our basement had a direct vent fireplace and the on/off was a simple 2 wire circuit and it was very easy to wire it into a standard thermostat so it could warm the basement to the level of 70 and then turn off.