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Jon Matcho

How to heat a freezing workshop?

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The problem will be how long you will have to run the heater unattended prior and post cure. It would be a first class bummer to watch all that plastic go up in flames!

 

The Cozy Girrrls have built a tent using PVC pipe as the frame so they will only have to heat the actual work area. There heater I believe is a bunch of incandescent light bulbs. Using that you could safely heat up the work material prior to using the heater (for creatures only) during the assembly and then keep everything toasty under the tent during the cure. It might even be somewhat cheaper than running the propane heater full-time.

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... So far I'm thinking about getting a radiant propane heater...

I had the same thought too, but the problem with radiant heaters is that they are radiant. You don't actually heat up the shop, just surfaces that are exposed to the radiant heat. From my understanding, everything used in the layups has to be ~75° F. Foam, glass, epoxy, and ambient.

 

The epoxy is no problem with a hot box, but the foam, glass and air are a different matter. The foam is a good insulator, and will take a long time to heat up thoroughly. Likewise, the air will not be adequately heated by a radiant heater.

 

You'd be better off with a forced air convection type heater, heating the air in the shop. Unfortunately, this takes a good bit more energy, and you would have to insulate your shop to make it more worthwhile. At least, that's what I'm planning on going with, once I get my garage a bit more insulated. Since winters are so long, dark and cold here, I'll probably build one of those PVC & poly tents as well, so that I won't have to heat up so much space.

 

Edit

Checking on the same site you listed, I found this 30k BTU garage heater that would be perfect with the optional blower installed:

Propane Garage Heater

Depending on insulation or not using a tent, you may need two of these.

 

-- Len

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The problem will be how long you will have to run the heater unattended prior and post cure. It would be a first class bummer to watch all that plastic go up in flames!

 

The Cozy Girrrls have built a tent using PVC pipe as the frame so they will only have to heat the actual work area. There heater I believe is a bunch of incandescent light bulbs. Using that you could safely heat up the work material prior to using the heater (for creatures only) during the assembly and then keep everything toasty under the tent during the cure. It might even be somewhat cheaper than running the propane heater full-time.

My shop is 20x20, x 10 high - so 4000 ft3 approx.

 

A 12,000 btu radiant propane tanktop like the Model 12-IR (Coleman brand) will give me a 10 degree C rise over outstide ambient temp, OR will maintain 15C rise as it gets cooler outside.

 

I also have a 45,000 btu model that will give me loads of heat - even a 35+ degree C rise, so about 22-25C on a -18 C day like today.

 

The big one doesn't go low enough in output so it gets too warm - even for me!

 

IF I was doing it again, I'd do something like the 30R which is 2x15k and independant burners.

 

I keep the heaters as far as possible from the fuselage, at least 6 feet, AND since heat rises, I run a large fan pointed at the ceiling at about 45 degrees to re-circulate the heated air. Without the fan, 90F at the roof and 55F at the floor is about normal.

 

Running the 12k on low (probably about 9k output) is great for overnight cures down to about freezing, and I'll get about 24-30 hours from the tank (20lb).

 

Yes, I have a CO monitor / alarm in the shop, but the good ventilation in there has kept CO from being a problem so far. Sometimes I feel the effects of lower O2, but I've never sounded the alarm! (ok, the shop leaks like a sieve!

 

/dan

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Interesting timing... just met a friend after this post who had just put in a natural gas radiant heater w/blower, which worked very well for him. He leaves on unattended quite a bit.

 

I think the heater Len pointed out is best for my needs: http://www.heatershop.com/garage_heater_gn30t.html

 

I tried to use an unvented+inefficient propane heater last winter, but after 15' all the O2 was practically gone (and the heater wouldn't run well once that happened). This was in my very drafty garage at the time.

 

Someone else told me that the indicator for healthy air is not so much CO, but oxygen. Apparently you can have BOTH low CO and O2 levels, which a CO detector will not alert you to.

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I tried to use an unvented+inefficient propane heater last winter, but after 15' all the O2 was practically gone (and the heater wouldn't run well once that happened). This was in my very drafty garage at the time.

 

Someone else told me that the indicator for healthy air is not so much CO, but oxygen. Apparently you can have BOTH low CO and O2 levels, which a CO detector will not alert you to.

That's my only worry, but I plan to duct combustion air for the heater. My garage is on the windward side of the house, and it has a vent on the windward side that the prior owners had ducted to the stove vent (before they figured out that it is hard to exhaust into the wind). I intend to route this vent to the heaters and use it for the combustion air supply.

 

I know the vent-free ones are supposed to be very clean and complete combustion, but I may also duct the exhaust. The humidity provided by the heater would definitely help hold heat, but too much could turn the room into a steamroom.

 

As an aside, that heater I linked before (for $189) is selling for $268 at Lowes, and $249 at Home Depot, without the blower. You found a good site.

 

-- Len

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Jon, I'm looking at heating methods for my unfinished shop too. I've looked at many options, everything from electric baseboards, to home made waste oil burners, coal stoves and LP heaters. I can get free wood, coal or waste oil, but these heaters are inconvenient and unsafe. I do not want to have to go outside at 3 am and start a fire or light a heater so I can build for 2 hours before work that day. I also don't want to have to take oxygen checks every 15 min to assure that I'm not being poisoned by CO. None of us should choose unsafe heat... fumes, fire hazards, or low oxygen hazards. For these reasons I have limited my heat choices to full automatic, and sometimes vented, systems.

 

Oil, propane, kerosene, electric (straight resistance), electric heat pump(300% efficiency), natural gas.... any others?

 

I did a small study on a few local heating methods. Your rates will vary from mine. I based my study on a 12000 BTU (input) heater running 24 hours per day for 28 days. Just for comparison.

Example: #2 Heating Oil = $1.72 per gallon, 139000 BTU/gallon, 12000 BTU/hour, 8064000 BTU/month, 58 gallons per month, Total = $99.78 per month

 

Results

Propane at $1.79 per gallon, 91502BTU/Gallon ==== $157 per month

Oil at $1.72 per gallon, 139000BTU/Gallon === $100 per month

Kerosene at $2.15 per gallon, 134000BTU/Gallon === $130 per month

Resistance Heat at $0.053 per KWH, 3413 BTU per KWH, == $125 per month

Heat Pump 1000 watts, 672 kwh per month at $0.053/kwh === $35 per month

 

At my rates, I'd be crazy to even consider propane or kerosene.

 

The heat pump unit is a Sunpentown portable unit that puts out 12000 BTU per hour. It only runs if the inside temp is 40 deg F or higher, so I'll need some resistance heat to get it going (My home has a heat pump, and electric resistors kick in on real cold nights).

 

I pay $0.053 per kWh for electricity.... that is the TOTAL cost, including all service charges. Unless your power cost is 4 times higher than mine, I will have to recommend heat pump heat. Am I missing something? Why do all new homes in NJ come with oil or gas heat? Why aren't heat pumps even offered? Its no colder there than it is here... I spent the first 16 yrs of my life in No NJ.

 

What are the current rates in NJ these days Jon?

 

Oh yeah, the Sunpentown unit is self contained, and Costs less than $500. They hotel type heat pumps look good to.

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Jon, I'm looking at heating methods for my unfinished shop too. .... The heat pump unit is a Sunpentown portable unit that puts out 12000 BTU per hour. It only runs if the inside temp is 40 deg F or higher, so I'll need some resistance heat to get it going ....

According to the spec sheet on the web, the minimum temp for operation is 62F. However, this does look like a nice unit, for what it does.

 

I pay $0.053 per kWh for electricity.... that is the TOTAL cost, including all service charges.

Probably due to the coal in the area. Electricity in the N.E. costs ~$0.14/KWH, or about 3 times what you pay.

 

I got a $35 Mr. Heater for my 20 lb. propane tank. I can heat my garage to 75 degrees for the weekend on a $10 fill. It would take a lot of weekends to make it worthwhile to buy a $500 heat pump, even at your electricity prices - at mine, there's no way it's cost effective.

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Good Point Marc... If we only plan on using the heat for 48 hours per month vs. 672 hours, then fuel cost doesn't really matter. We should buy the lowest cost heater. But if we plan on keeping our shops warm during the winter, fuel becomes an issue. Propane = $5 per day, heat pump near coal = $1 per day. Heat pump near civilization = $3 per day.

 

If we heat 32 days per year:

Propane = $160

Heat Pump or Oil = $96

 

If we heat 120 days per year

Propane = $600

Heat Pump = $360

Heat Pump Near Coal = $120

 

It can be cost affective, and there are some total package heat pumps from a nursing home on ebay right now, for $50 a piece. The kind you see in hotel rooms. Only problem is that they are about 500 miles from me... search for GE zone line 5000 on ebay.

 

By the way, the cooling inside temp range is 62F to 110F, the Heating inside temp range is 41F to 81F.

 

Now, about this airplane thing :D

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I'm in the process of erecting a heat tent over my work table similar to what the cozygirrls have done. This seems to be the most practical and should be able to maintain an acceptable temp range for my needs. The cozygirls are using a small space heater inside the tent to provide the heat. I'm looking for a thermostatically controlled, electric space heater to heat my tent. Does anyone have a lead on such a unit?

 

Remi

Cozy IV - Starting chapter 4

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What are the current rates in NJ these days Jon?

NJ/PSE&G electric fluctuates, somewhere between $0.10 and $0.13/kWh.

 

Natural gas is similar to propane as far as I can tell, amounting to $1.15/therm which amounts to ~$0.23/hour @ 20,000 BTUs. Running all month, which I may need to in order to keep my garage pipes happy, will cost me $171 -- worth every penny considering the imaginable consequences (see picture).

 

I just purchased a Reddy Garage Heater GN30T from Amazon w/blower for $170 + $46 ... $215 and free shipping. Time I got off the dime and moving.

post-386-141090152831_thumb.jpg

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I have an attached garage 20X24 Ceiling is about 12-13' high. I really see no benefit to leaving the heat on all the time. The Epoxy is in a hot box with a light bulb keeping it warm. I have a kerosene heater I think it is a 28k BTU heater and it does a really nice job of heating up the space. In addition to the kerosene heater, I have an electric radiant heater dropped down from the ceiling, I can point this at the work table or my fuselage and this does a tremendous job of warming up the Fuse prior to any glass work. ($50 at Lowes.) I also have some of those LP tanktop Radiant heaters, but I don't use them very often...occasionally. This weekend,it was in the teens here in Jersey. I completed a large layup and the kerosene heater did a great job of maintaining 75F.

 

If you decide to go the Kerosene heater route, Only burn the 1K or K1 fuel..DO NOT BURN Diesel fuel...very bad results..

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I really see no benefit to leaving the heat on all the time.

My deal is that the prior owners of my house added a large bathroom on top of the garage for minimal cost. The result is a poorly insulated bathroom that freezes every year, which would only benefit from having a warmable garage underneath. The other side effect from this "addition" is that 2 lolly columns were added inside the garage to support the added weight.

 

I could use kerosene and whatnot, but I just don't want to deal with refillable tanks, fuel, and anything less than 99% burn-efficiency. So there. ;)

 

I do like the idea of the radiant heater though, paired with a curing tent as Remi pointed out. I may do that as well, or just pay the piper.

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...I'm looking for a thermostatically controlled, electric space heater to heat my tent. Does anyone have a lead on such a unit?

If you can't find on they are pretty easy to make if you stick to electric heaters. You can use any old mechanical thermostat connected to a relay on the supply power to the heater. Whenever the relay opens so does the A/C to your heater.

 

If you don't mind cutting open the heater (high and lethal voltages) and the heater you have uses a low voltage to control its thermostat, you could wire your thermostat in series with the heater's existing thermostat and do the same. Of course all due caution should be observed because the devices have lethal voltages and kill the unwary.

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If you decide to go the Kerosene heater route, Only burn the 1K or K1 fuel..DO NOT BURN Diesel fuel...very bad results..

What makes you say that? And what evidence do you have to back it up?

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Because I tried it Marc, and it did NOT burn cleanly. Lots of soot and smoke. I could not stay in my garage when the heater was operating. Switched to Kerosene, and now I really can't tell that the heater is on. The only time it puts out a bit of smoke is on start up or shut down...That's it!!

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Because I tried it Marc, and it did NOT burn cleanly. Lots of soot and smoke. I could not stay in my garage when the heater was operating. Switched to Kerosene, and now I really can't tell that the heater is on. The only time it puts out a bit of smoke is on start up or shut down...That's it!!

Hmmm. Must be the heater you've got. I built two planes using diesel fuel in my 30K BTU kerosene heater and never had any soot or smoke at all, nor any residue on any parts.

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Well, I doubt it is my heater, seems to be a pretty good one. Maybe it was bad Diesel fuel. I now recall a while ago you mentioning using diesel fuel with good results, which was why I tried it. But since my experience with it I never tried it again.

 

So..

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While building a fire in the fireplace, I remember my grandparents had an old iron wood stove. The darn thing, as small as it was easily heated more than a few rooms. It took little time in the morning to crank up the heat. I guess the downside is that you will have to keep stoking it. Still if you have firewood stashed around your place it probably will work well for you.

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Is it possible the kerosene and diesel on the same wick was the problem?

I Do not think so Nathan... I had not used kerosene at all yet. I was on my 2nd or 3rd fill up of Diesel. Maybe I got a bad batch.....but anyway kerosene does work better in my Kerosene heater

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I built my shop out of 4 inch styrofoam.Walls ceiling and doors. It measures 12 high x 16 wide x32 ft long. All this is in a 40 x80 pole barn. Has 2 ton monorail across the middle with two hoists. My EZ is hanging overhead . I can raise or lower or roll over to work on. The shop has two heating sustems: A 50000 btu ceiling hung forced air natural gas furnace and a wood coal 60000 btu furnace setting onthe out side and ducted in through the wall. This to burn up the scrap wood on the farm. In addition there is a wall mounted airconditioner (15000 btu) . In addition there is 5 doors in each end so I can drive through with and work on my backhoe or my 32 ft motor room. Makes a great spraybooth as there is also a 20 inch exhaust fan. Expenseve. Not really . Most is salvage materials from what I had on hand. Out of pocket was less than 800 dollars. Pictures later to anyone interested. Ray

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Checking on the same site you listed, I found this 30k BTU garage heater that would be perfect with the optional blower installed:

Propane Garage Heater

Depending on insulation or not using a tent, you may need two of these.

I have the natural gas equivalent of that model, being installed this week. It's rated for "1,000 square feet -- suitable for most 2-car garages".

 

I'll let you know how it performs once fired up.

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My shop heater was installed today. It's been running on the lowest setting (guessing 15,000 BTU) for the past couple hours. The outside air temp is 18F and inside at table level is 45F.

 

I'm happy with that for starters, but will be looking for substantial improvements once I get some good insulation installed in the spring. In the meantime, I'm going to put panels and plastic up over the doors and windows. Hopefully that will get me up to 70 degs or so.

post-386-141090152838_thumb.jpg

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Install a ceiling fan and leave it run on low speed all the time. The will keep the air stirred and prevent condensation on the floor when the temperature starts getting above freezing.

 

Waiter

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