I'm looking for advice......I'm wrapping up the renovations to my man-cave / shop and will need to heat the space. The area is 650sf in size, constructed with cmu and is uninsulated.....its part of a large 5-car garage / barn structure. I'm not sure if I should go with a propane or electric heater.

That is beautiful!

I guess the big question is how often do you want to heat it? Being uninsulated, heating it all winter either way isn't going to be cheap. Do you have 240v at the garage? Are you going to paint or have other flammable gasses in there?

Propane is cheap right now. It can also heat the space quicker than electricity. You will need a vent.

Check out Modine Hot Dawg heaters. For about $600 you can get a 30,000 btu heater which is plenty for your 650 square feet. Price out electric heaters in that size along with electric needs and you'll find propane is cheaper.

Propane, Modine Hot Dog.

I have radiant floor heating in my garage, with pex tubing in the concrete. I use that to keep the garage to a minimum above-freezing level over the winter. Love that thing when it's working, kinda nice to lay on the warm floor...but I digress...Anyway, that method does not heat up the air quickly. If I leave the radiant heating at, say, 45 degrees, and I want to work in the garage, I have to give it several hours to get to a comfy 60 degrees.

I've had plans for 4 years to install a Modine for quick air heat-up - after all, I already have the propane - but in the interim I'm using a portable kerosene heater that does a damn fine job on its own. It's a DynaGlo I bought from Lowe's, 23,000 BTU. I fire it up an hour or so in advance and it heats the 600-ish square foot 2-level space to a comfy level from 45 degrees. And it's portable, installation was zero, and I only go through 5-10 gallons of kerosene per winter. I'd call that my easy button for now.

On the other hand, your space is uninsulated, so you'll need a lot of constant BTUs. That's where the Modine Hot Dog comes in. If you have the ability and resources to install propane then this is what you're going to want. Contact your local oil/propane dealer and you can rent a tank from them, and if they don't do the plumbing I'm sure they can refer you to someone that does.

And then enjoy the warmth...

Before:


During:


After:

I went with a 220V electric that I wired to a 10' cord. It's on a stand so I can move it around to head the area I'm working and not the entire shop. Granted, I'm in CA but it does get cold enough that it's less than comfy without it.
Make a big difference.

The problem with ventless kerosine and propane blow torch style heaters are they throw CO2 and water into the air. CO2 is bad for you and water is bad for your tools and such. Those ice cold tools attract the moisture like a cold soda on a hot day.

Electric resistive heating would be expensive to use, go with natural gas or propane. I'd stick with a 80% non-condensing Goodman furnace. It's just over 400 dollars (my cost) and a addition 20 bucks for the propane conversion kit for the gas valve.

Since you would most likely just use this heat sporadically, you need something that is fast recovery, which means oversizing the furnace for the space needed. I think 80k BTU would be more than plenty. You can either set the furnace floor level, or you can hang it, fielders choice.

For cars, tools, etc., ventless is garbage.

Yeah, but what's a viable affordable alternative? When you're trying to warm an unheated garage from potentially 15-25 degrees to a comfy 55+, resistive electrical heating is going to burn you up the butt at Northeast electrical rates...guess it depends on how many times you're going to use it over a winter.

Propane heats faster, heaters are under 1000 bucks, just make sure you have a professional HV/AC guy install your venting and put in a couple C02 detectors.

I have a regular home furnace in my 1200 sf shop and run it off propane.. The home furnaces you can run air filters to clean the air and cost about 600 dollars for a small one .. Plus a 90percent efficiency model draws all the moisture out of the air.

I put a 5K watt electric heater in my 650 SF garage.

I considered a Modine propane, but the electric unit was almost $ 500 less, didn't require any venting, and gave me a good reason to run a 240 circuit to the garage for a compressor...or a tesla . Yes, ConEd electricity is pricey, but I figure the money I saved on the unit and installation over propane gives me maybe 10 winters of free garage heat. It mostly gets used on weekend days and doesn't have to work so hard since the garage rarely gets below 40 even on the coldest days.

FYI...here's the one I got....


https://www.amazon.com/gp/product/B0000AXEZ...=UTF8&psc=1

I have looked at similar units. Can you remote the on/off or just use the breaker?

Since NY code requires a dedicated breaker within 6 feet of the unit, I just use that as the "switch".

The thermostat on the unit works well. If I put it on the lowest setting, it only kicks on below 50.

Thanks - I have 10' ceilings in the garage and would need a remote switch or use the breaker.

The idea that a gas heater will heat up a space quicker than an electric heater isn't exactly correct. What decides how fast (or slow) the space heats up is the BTU/Hr output of the heater you install. Now, the air temperature that is coming off of the electric furnace can be a bit lower than what's being pushed by the gas furnace so people generally 'percieve' gas furnaces to be warmer when standing in the air stream, but the reality is that both do the same job. My preference for garage/shop space is radiant heating as it is much more comfortable to work in and much more efficient. Note that it works by heating up the surrounding surfaces rather than the air. So opening and closing the doors for short periods won't affect the temperature of the space! Check out something like the spaceray infrared tube heaters, a bit more upfront cost but cheaper in the long run becuase you'll be using less fuel to run the thing.

That said, what you install is really going to depend on your use/needs for the space and your budget. Looks like you are in Philly, so you have 'real' but not crazy winter temperatures. Your best bang for the buck will be insulation and weatherization. It's amazing how much just a little insulation will do! Once insulated then look at heating the space, and when you do ask yourself the following questions:

1) What temperature do you want the space to be? Are you Ok wearing layers or does it need to be T-shirt territory? Is this just to protect the stuff inside the garage from large swings in temperature?

2) What are the outside temps going to be when you are hanging out in there?

3) If you are comfortable with numbers then you can calculate the size of your heater on your own (if interested I can throw some equations your way and I'm sure many other here can do the same), if not then I suggest you find someone who is or talk to folks in your area who have garage heaters to see what sizes they are running. Climate and your specific garage (namely insulation, draftyness, and total area) have major impact on this! 80,000 BTU's may be overkill for one space and barely enough to maintain 55 degrees in another.

I agree, if possible seal and insulate and then you can afford to keep an even comfortable temp all thru the cold season. Temperature swings causes condensation and in the long run rust. Even just four inches of insulation in the ceiling will affect the needed heat alot.

falcor75 is correct.....insulate first.......if you don't and just throw a bunch of heat in there, cold to hot, all your tools will rust....not good....insulate and keep at a moderate temp. Best, Mark

because you will probably want to cool or at least dehumidify the space in the summer.

+1 on the Hot Dawg propane heater.

My Dad put one in his shop years ago. Heats up the space quickly and has a thermostat.

I work in my shop all the time, walls and ceiling are R-20. I heat to 49F all the time and it can heat the shop to 70F with-in 30 minutes. For normal working conditions, when not painting/glueing, I heat to 60-62F.
It will maintain 70F even with the paint booth fan running.

I have an over sized, 98% efficient, direct vent propane furnace, hung from the ceiling.
The big advantage of the direct vent is there's no open flame in the shop, therefore no insurance issues what so ever.

I used to heat with wood, insurance company made me remove it.