View Full Version : Shop heaters

11-17-2007, 06:16 PM
Hi Everyone,

I just moved to a new place and my new shop is in my garage (detached, two-car, insulated everywhere but the garage door). I'm looking to get a heater for it and I was wondering if anyone has opinions about the various styles of heaters and what their running cost is. The garage has a gas line in it that went to a garage furnace that no longer works and is disconnected. The types I've been looking at are:

A hang-down natural gas-powered garage heater, which is what was there before. The model I'm looking at getting is a 45,000 BTU input, 36,000 BTU output max that needs to be vented and controlled by a thermostat. Since that was what was already in there, neither of those things are problems. This model has the best warranty of the bunch and is made in the US, but is also the most expensive.

A small ceiling mounted electric heater that runs on 240V. The max output on this one is 7500 Watts. Natural gas costs a lot more than electricity on my bill, but I'm wondering if I'll use so much more electricity that it will offset the difference.

A wall-mounted vent-free Natural gas infrared heater that has a ceramic plate heating element. The biggest one I've seen at the stores (Lowes, Comfort Glow brand) is 18,000 BTU, which strikes me as insufficient for a two car garage, especially since it doesn't use a fan, even though it says it will do the job. I'm curious if anyone uses one of these and if it is produces a "hot spot" around the heater and cold everywhere else.

A Kerosene powered convection heater. The one I'm looking at will easily heat the space, but I wonder about the run cost versus the others on this list. The box says it goes through 1.9 gallons of kerosene in about 12 hours. K-1 is around $15 for 2.5 gallons here, so that strikes me as high.

Your thoughts are greatly appreciated.


Forrest Addy
11-17-2007, 06:26 PM
Avoid unvented gas and keposene heaters. They build up double the weight water vapor per weight of fuel burned. If your shop is well sealed there's the CO build up (there's always some) and the CO2.

You might consider pellet fuel. I heat with pellets for about 2/3 the cost of gas or oil and half the cost of electricity (relatatively cheap here).

Best of all is in-floor radient but it has a large initial investment.

I suggest using the existing flue chase and a pellet stove. Your local dealer may have a trade in. OTH pellets may be more expesnice in your area. They are about $220/ton in Western Washington state.

There is also overhead radiant gas tube heat. It's vented, heats objects, and if you have the vertical clearance even.

11-17-2007, 06:53 PM
Stuart... I have tried many of the types you are asking about.
I have used un vented NG heaters. You can get them 30,000 btu I have one. It has a blower mounted in the base and is controlled via a thermostat. I ran these in the house.

As already stated they add moisture, and harmful emissions. Some call it sooting. It leaves a sticky residue all over. This heater and another I used that did the same is not defective and I had the supply pressure checked. It is just the nature of the beast.

They are however very cheap to operate and they really heat well.

Kero heaters..I am using them in my shop now..I wish I was not as stated they do produce moisture but I have not seen any adverse effects from them. My shop is finished with full insulation and drywall. They do not seem to heat that well but the worst is they are not controlled. they just run full out. As they are a radiant style heat it takes a while for them to heat things up (wick type) and then they keep going until it gets so hot you have to turn them off. Constant starting and stopping.
I also have a torpedo fan forced and it is 60,000 it is thermostat controlled and heats quick and turns on and off by itself. The drawback along with moisture is fumes. It is like working in a truck shop. I run K1 kero in it but it will run many types of fuel. K1 kero is the least smelly but as stated the CO2 will get you. It does burn a good amount of fuel and like you said kero is pricey.

The best I would say would be a NG forced hot air mobile home vented furnace. Is very efficient, comes in up to 60,000 btu or higher (at least the ones I saw and used) and will be the most efficient.

11-17-2007, 07:54 PM
A hang down NG space heater of 25K BTU will do you a good job, the kerosene heaters are a PITA, with the NG heater you just set the thermostat and enjoy, no hassles.

11-17-2007, 08:11 PM
Do NOT use an unvented heater. The moisture issue is a real problem, everything will rust. Those "unit heaters" that hang from the ceiling work well and take up no floor space. They're easy to install, using a double-wall pipe through the wall. We put one in a friend's garage, I think it was bigger than 25,000 BTU. IIRC, it was the middle of 3 sizes available in the Grainger's catalog, but I'm unsure if it actually came from Grainger's.

11-17-2007, 09:09 PM
[QUOTE=hornluv] A small ceiling mounted electric heater that runs on 240V. The max output on this one is 7500 Watts. Natural gas costs a lot more than electricity on my bill, but I'm wondering if I'll use so much more electricity that it will offset the difference.

What kind of electric heater did you find that has an output of 7500 watts? I really like the cleanliness of electric heat and I've been looking at heaters for my detached garage. My shop isn't in there but I'd like to keep it around 50 degrees through the winter just to keep it comfortable for the occasional job out there.

11-17-2007, 09:26 PM
Hey Guys,

Thanks for the responses so far. I'm renting this place, so the price of pellet stoves is a bit prohibitive for me. I'll spend that gladly when I have my own house. I'm definitely leaning towards the NG garage heater.

Japcas - I found the electric heater at Blain's Farm & Fleet. I think any place that focuses more on people who actually work out in shops, farms, garages, etc would probably have something like it. I haven't seen anything close at the big boxes. They're more interested in selling to clueless homeowners who don't know that hardware stores and lumberyards are much cooler places to hang out. :D

Frank Ford
11-17-2007, 09:40 PM
I have two of these in my shop:


They each run 3000 watts, and they do a great job. I have them individually switched and on a spring-wound timer, so there's no chance of leaving them on.

Now, the big deal is that they are radiant heaters on the ceiling, so they heat ME immediately from the top down, starting with my own personal control module (once covered with hair) when I switch them on. Takes a really short time to make me comfortable, so they don't stay on very long. Cheap and effective heat for my shop. . .

Dick Plasencia
11-17-2007, 09:45 PM
I hesitate to join in since you all will say I'm wrong. However my oil fired salamander 50,000 BTU heater has done excellent in keeping a two car garage in Iowa nice and toasty even during a roaring blizzard. I burn red #1 diesel which is tax free and about the same as kerosene. Last batch I bought was $1.67 a gallon. I use about one gallon a day or less. I don't see any moisture. After 31 years I'm not dead or poisoned yet from the unvented fumes. But your results are sure to be different. Anyway it works for me although it can be noisy at times.

Your Old Dog
11-17-2007, 10:33 PM
I just scrapped a wood burning stove for a propane wall furnace of 30K input/20K output for a 400 square foot shop that is well insulated in Western New York. It will heat the shop to 65 degrees in 1 1/2 hours when it's 45 outside. Sooooo, ain't know way in hell it's going to be adequate when winter really gets here at 20 degree. I'm now looking for a 75K ceiling unit that vents to the outside with electric pilot so I can flip a switch in the house to turn on the furnace. 75K should put out enough heat to warm the shop up in about 20 minutes time when the temps drop to 20 degrees. Waiting 1 1/2 - 2 hours for heat sucks.

I have a vent less Big Buddy infrared propane heater at 20K but as Forrest mentioned, they really make the place damp. I want a chimney and I bought a CO detector just to be sure.

11-17-2007, 11:19 PM
I used a NG forced air furnace that came out of a house that was to be torn down. You really can't beat the convenience and simplicity. I want to put heat in my mothers garage now and I recently went to a Heating and A/C shop and asked the folks there if they had, or would soon have any furnaces that worked well but were heading for the scrap yard. Some folks upgrade for different reasons. they called me thursday and told me to come and get it next week. I guess i'll stop and get a pizza and drinks for them on the way to get it. Not all shops are so nice, some want you to pay a premium for that kind of thing, ask around at a few shops or purchase new outright, they really aren't very expensive when you consider their life expectancy.

11-18-2007, 10:07 AM
Thanks again guys. I knew I could count on you for good advice.


05-14-2009, 02:26 PM
You need a Hot Daug. Hangs from the ceiling. Not cheap. Got one and I know it works great.


05-14-2009, 07:57 PM
You need a Hot Daug. Hangs from the ceiling. Not cheap. Got one and I know it works great.

Thanks for your input, but this thread is a year and a half old. I've got a very nice garage heater that does a great job of heating the shop.

05-19-2009, 11:41 PM
I have been using the wall mounted "vent free" gas heaters for ten years now with no problems with moisture. I monitor the moisture closely. I have two "vent free" heaters but use them to maintain a minimum temperatures. I also run fans to circulate the heat. To make the shop comfortable to work in I run electric heaters for an hour or so and I think it helps control moisture. No doubt a vented furnace would be dryer heat.

I have the worst moisture problems in areas that are unheated like my motorcycle shed.

05-20-2009, 10:23 PM
Search the net for "Hunter Wall Mount Furnace" they may be operating under a different name now though. These are the cat's ass. Natural gas or propane. They mount to the wall, protrude approx. 8". Rear vent and combustion air intake (through the wall). The combustion chamber is closed from your shop so no source of ignition should something spill. The insurance companies love them. I heat my 18 x 24 shop all winter in Canada. Leaving the stat set at 45 deg. f at all times except turning it up when I am working out there only adds about $20 a month to my gas bill. All the tools and toys stay happy with no condensation and corrosion issues. The shop is well insulated.

Mr. Mike.