Shop heat... How many BTU's?

So, my "shop" is basically an older 40x60 pole-barn, and with the $2014 Challenge being moved to June, I don't have time to wait for warm Spring weather to start my build. I am going to need heat.

Unfortunately, losing a few months of build-time for the car means I won't have time to re-do the electrical, or deal with getting natural-gas service run. So I'm looking at kerosene "salamander" type heaters.

The building is divided in half, which is good, because I only have to heat 1200-sq-ft. But the ceiling is only half sealed-off, so I'm still gonna be unintentionally losing heat to the "storage" half of the building.

Does something in the 210-300k BTU range sound adequate, taking into consideration that my joints don't like anything below 50°F?

I have a 26 x 32 garage. Stick framed, sheathed and sided, asphalt shingle roof, uninsulated, in Maryland near DC. 60 amps of 220 on hand.

Needing to lay all the parts of a fiberglass race car body in January/February, I needed heat, and plenty of it - after slicing and dicing the equation every way, I ended up w/ a 45kbtu propane radiant tube unit from Mr. heater. I hung it near a wall aimed toward the middle at a 45 degree angle and ducted both the intake and exhaust sides outdoors through adjacent walls but a few feet apart. (A wet layup fiberglass race car nose could potentially result in an explosive atmosphere...) I got a 100# propane tank and regulator which lived outside. I ran black pipe with flex tubes at the ends for the gas. My heater cane for natural gas so I got the correct jet and conversion for the regulator and a water manometer to set the regulator. It's an easy conversion.

Radiant tube heaters are great 'cause they can be closer than 8' to the floor, and they don't heat the air - they heat the stuff. I'd turn it on in the before breakfast on a freezing day and it would be warm enough to work after an hour. If it was on all day, the concrete slab would be indoor temp and the room would still be much warmer than outdoor temp the next day.

Somehow I ended up with a second one, new, in the crates. Also set up for NG but w/ the jet and reg kits. Inquire if you're interested.

No way to answer the question without knowing at the least how cold the ambient air will be getting. What is overkill in 40 degrees is totally inadequate at 10 degrees.

The opening at the top certainly means heat loss, but what kind of air flow into the space exists? If it's sealed, the heat will rise slowly. If it's open, it'll shoot up there like in a chimney.

If nothing else, radiant heat, as mentioned above, because you can locate it right at you. That's why its even somewhat effective outside in the blowing wind and snow.

grafmiata wrote: So, my "shop" is basically an older 40x60 pole-barn, and with the $2014 Challenge being moved to June, I don't have time to wait for warm Spring weather to start my build. I am going to need heat. Unfortunately, losing a few months of build-time for the car means I won't have time to re-do the electrical, or deal with getting natural-gas service run. So I'm looking at kerosene "salamander" type heaters. The building is divided in half, which is good, because I only have to heat 1200-sq-ft. But the ceiling is only half sealed-off, so I'm still gonna be unintentionally losing heat to the "storage" half of the building. Does something in the 210-300k BTU range sound adequate, taking into consideration that my joints don't like anything below 50°F?

300,000 Btu/hr sounds a bit high. I'd be looking around 100 MBH (MBH is actually a thousand BTU/hr) But it's SWAG. Strictly Wide Ass Guess.

In reply to motomoron:

PM sentified

For homes with average insulation and windows, in a kinda normally cold area (Mid-Atlantic), a rough rule of thumb seems to be 10 BTU for every square foot of living space. So a 1200 square foot house would need about 12,000 BTU to keep it at a livable temperature (68 degrees or so). 220VAC baseboard heaters put out about 5000 BTU for every 6 foot length (1500W).

For an uninsulated garage, with a leaky roof, I'd start out at least twice that- 25kBTU. I do know from experience that a 75kBTU propane blast tube will heat a 600 square foot concrete wall garage with 12' ceilings and a metal roof VERY quickly. More BTU will warm it up quicker, but if you have to manually shut it off and on (my tube wouldn't put out less than 75kBTU, for example) that can become tedious.

In reply to grafmiata:

I believe there might be a slight btu bump by running diesel in a kerosene salamander.

I personally have a 40k salamander that can heat my uninsulated 20x20 garage quite well. For your case, 210-300k should be fine with the building halfed

In reply to motomoron:

I've looked into those, and they are in the plans for later down the road. But I only have one day off a week, so for now I just need something to get me thru one NW Ohio winter so I can work on the Challenge car, I stead of the shop.

Happen to have a rural king near you? Their Black Friday sales normally have these suckers in them for great deals. Dad got his 210k one last year for $199

http://www.ruralking.com/mr-heater-210k-btu-forced-air-kerosene-heater-mh210ktr.html

This was my shop heating system for decades when I lived in the North:

I'm serious.

Bear with me- it's not that far off the subject.

First off... a salamander is a great way to die of asphyxiation. Use it wisely.

Having said that, I've used them a lot, both in the shop and on construction sites.

But I don't use them to heat a space, I use them to heat people. You really don't need to heat the space and maintain it at a comfortable level throughout. If you try, that's when people die.

With a salamander, you need ventilation. I use them with doors wide open. They are perfectly adequate to heat concentrated work areas waay beyond what is comfortable, regardless of how big the room is, or how cold outside.

If you put 300K BTU's in a sealed space, if will consume all the oxygen long before you realize it.

So, I suggest a combination...

A decent insulated vest (or better yet, an insulated jumpsuit), plus a medium sized salamander with the doors open will heat you and your immediate workspace with plenty of room to spare. It will not heat the far corners of the shop comfortably enough that you can roll around on the concrete floor and do brake jobs in the nude.

This should solve your problems, except for when it is time to paint. But a salamander won't work very well for painting anyway, because they pump way too much humidity into the air. Expect condensation dripping off windows and metal surfaces.

No lying, I've done many a job outside in sub-freezing weather, on the cold ground, bundled up. A 500W halogen lamp shining on you and your work helps keep the chill off, too.

I hate Kero heaters, personally, I think they stink. Literally. Propane is cleaner, but still makes CO2 as it burns so you need to have a source of ventilation to get O2 in and CO2 out.

In reply to SVreX:

Alternatively, when in an enclosed space, you can bring it up to a reasonable temp(say 50-55) and set the thermostat to that......if his barn has 4 walls and a roof, it will do that job much quicker than running you out of oxygen. Yea, I could see what you're describing happening if you tried to heat a semi sealed enclosure to 90.

We also run diesel in our kero salamanders.....slight soot, but it doesn't smell as bad.

In reply to yamaha:

While I'm sure they make them, I've never seen a salamander with a thermostat. I've seen hundreds.

And no, I've never tried to heat any space to 90 with a salamander.

So, if the suggestion is he look for a salamander with a t-stat, that might be a good idea.

But a kerosene (or diesel) burning open flame heater is always going to consume oxygen, so running it in an enclosed space is still dangerous. Not smart.

They ALL say to use in a well ventilated area.

Might I suggest using something designed for an enclosed area? Like a used household oil furnace? You can convert those to burn waste oil.

I've only ever used a (small) salamander aimed in the workshop corner of the garage, with the side door on the other end cracked open several inches. Or pointed under the car I was working on.

In reply to SVreX:

Perhaps its a northern thing.....mine and dads 2 all have ambient t-stats.

In reply to yamaha:

Perhaps. Except I'm from the North....

Still doesn't change that they are NOT designed for enclosed areas.

I bought one of these from the local farm and fleet. Its awesome. Very happy with it.

http://www.amazon.com/Mr-Heater-MH200CV-000-BTU-Convection/dp/B0000C6E39#immersive_view?1385171756039

The way the building is set up, I'm not really concerened about oxygen-deprivation. 16'-wide overhead door on the work side of the building that I can crack a bit. The other side of the place has an 18' sliding door that I can open for airflow. Open doorway between the two halves of the building.

Obviously, a salamander-type heater is less than ideal, and is not my long-term solution. But with my current schedule, I feel that it's my best option as far as this one winter goes.

Looking at a 300k BTU, with thermostat. Nuke the place to a tolerable temp, then just maintain from there.

I used those little radiant heaters that clamp on to a 20 lb propane tank in the ex-g/f's garage. That with some layered shop clothes worked well enough when I was working on her cars. "Venting" came from old, poorly sealed garage doors and a large opening in the ceiling for the stairs to the attic. I could even get away with two of them running without a problem. I did run into problems running two after the garage doors were replaced with ones that sealed better.

Do whatever you can to get yourself off the cold concrete. I would surround the car with 2x2 1/2" thick rubber mats I bought at Sam's Club. Even with insulated boots, it was a big improvement.

Oddly enough, with a little bit of heat and prep, I can deal with the cold... but working in the garage in the middle of summer w/o A/C... no effin' way...

In reply to Ian F:

Yeah, I agree on working in hot, humid weather.

I am fortunately at a point where I'm spoiled at my job... I work in an automotive plant that is climate-controlled. More for the robots than for the people, but it's roughly the same 68-72° every day at work...

I hate being cold, and I hate sweating. But being cold is worse, because all the stupid E36 M3 I did when I was younger haunts me with pain.

A lot of those wall mount vent free radiant propane heaters have feet kits available for them so they don't have to be wall mounted and have safety features like low oxygen shut offs. A 5 element radiant heater on the floor aimed in the general area you'll be working in and a 60-100# cylinder of propane ought to make life bearable, and easier to stay conscious in an enclosed space than a kerosene salamander.

I've got the cordless Mr. Heater Hero forced air propane heater, it's alright, fan will run about 8 hours on a full charge, and a 20# gas grill sized propane cylinder will last about twice as long as the fan. It does increase the CO2/dead risk. I usually had it running for 45min to an hour and off for 30min or so in our uninsulated 1 car 14' ceiling garage during central OH winters.

I accidentally had some brake cleaner vapor/overspray get sucked through the intake of the heater once, it was a really bad experience. Five minutes of coughing, couldn't catch my breath, tunnel vision you get just before you pass out. I stayed conscious but it made me extra cautious about anything I did around the heater, when and where I used it.

• Lee

Keep in mind that unvented heaters, whether propane or kerosene, are putting the products of combustion into the heated space. We've discussed concerns regarding carbon monoxide but not the other---water/humidity. Both types dump a bunch of moisture into the air; if memory serves it's in the neighborhood of 3 pounds of water per pound of LP burned and something similar for kero. Prepare to watch surface rust develop on uncoated metal and forget about doing any painting.

Jeff

Ian F wrote: Do whatever you can to get yourself off the cold concrete. I would surround the car with 2x2 1/2" thick rubber mats I bought at Sam's Club. Even with insulated boots, it was a big improvement.

Even some old cardboard works for that.

The part I hate most is grabbing the cold tools, because I hate working with gloves on.

I've got a pellet stove in the (single car) garage, which is attached to the house so even when its -40 it (hopefully) stays mostly above freezing. If you've got the time/money, it might be a solid investment. Mine gets the garage toasty warm in 20-30 minutes and since it pulls its air from outside and vents with a chimney there's much less risk. T-stat controlled too. The pellets take up space but a couple 40# bags should keep you warm for a couple days of work easy.

In reply to skierd:

Thinking about a pellet stove in the future. My original plan for the winter was to redo the electrical and add more insulation to the shop, as well as a permanent source of heat.

With the Challenge being moved ahead by a few months, the priority has changed to getting a quick, workable suction to get me thru this one winter so I can start pulling cars apart.