: Hello All,

: I am freezing in my shop 20ft x 18ft, 3 double pane windows, 2
: large swing-out doors, peaked roof stick built shop, non
: insulated. I plan to staple 2 layers of cardboard on the inside
: walls this spring.

: Went to the internet and found "Mr. Hero" cordless
: (internal re-chargable battery good for 8hrs-recharge fully in 5
: hrs.). 35K BTU. runs 12.5hrs on 20lb tank. This unit comes
: 10ftLP hose and regulator.
: It sells for $151 plus $8 shipping.

Ok, so you'll want to turn on the heat about 2 hours before you go into work there. Work for 4 hours a day, and the tank will last you 2 to 3 days.

What do you pay for a 20 lb. tank of propane? Around me it goes for about $20 and up. That is roughly $6 a day for heat, or about $180 until spring. If you can get downfall wood for free then get a wood-stove heater and a chain saw for about the same price. Torpedo style kerosene heaters may be about the same price as the propane heater, but deliver more BTUs per hour. Preheating the shop would be faster, and you could cycle it: run it an hour, turn it off for 1/2 an hour, and so on.

My truck (Freightliner) was heated with an Espar diesel-burning cab heater which burned under a quart of diesel fuel an hour, and kept the cab toasty in the coldest weather. Espar also makes diesel heaters for boats: http://www.espar.com/html/applications/marine.html They are not cheap to buy, but I have had no problems with their reliability. on trucks they save so much fuel vs. idling the engine to stay warm, that they pay for themselves very quickly.

If you have any mobile home courts near you, ask around about any old units which are being disposed of. Salvage the heating system from one!

I'm not sure why you want a battery-powered heater. Fans on most heaters draw little current and would work off your extension cord.

How are you heating your home? Gas, oil, coal, electric? If gas, look for a ceiling-mounted gas-fired infrared heater. The infrared heaters heat the items in the room, not the air. It si more efficient, and works fast. I've seen wall mounted units which did not need to be vented in the $200 range, and ceiling mounted units starting around $400. Your natural gas bill would go up, but natural gas is not as expensive as small tanks of propane. If oil, look for a small oil-burning home furnace. You might get an old one for free (haul it away!) when people decide to upgrade.

Insulation is your first concern. Keep what heat you can generate and you won;t need to make a lot. A few sheets of paper doesn't give much insulation value unless you can trap some dead airspace between the sheets. Staple the first layer of paper to the studs, then nail firring strips (1x2s) over the edges of the studs and cover that with your second sheet of paper to give you a 3/4" thick airspace. You can use thin, cheap, plastic wrap instead of paper, too. Building codes don't like this. Those paper walls are fire hazards.

If you have room and sunlight access near the shop, you can make a solar heater from plywood. Basically, you want to mount a plywood box aimed at the sun. Cover the front with window glass or plastic sheeting, paint the inside of the box black, and run an insulated tube to the shop. Flexible, insulated heat ducts are easy to work with for connecting things. Get hot air in during the day and there will be less demand on whatever you use to heat the shop in the evening.

Get some copies of Mother Earth News from your local library and go through the back of the issues, looking at all the alternative heating options available.

You can buy a generator and use that to power electric heat for your shop. it would also serve as a backup should your homes electric system fail. 1500 watts yields about 5200 BTU. You would want at least a 4500 watt generator to yield 15K BTU, and let it run a while. You can use lots of lightbulbs to not only illuminate the shop, but provide heat. 15 100-watt light bulbs gives off 1500 watts of heat (5200 BTU). Cheap outlets and lots of bulbs will warm you, if you can supply them with power.

Good luck in staying warm while you work. Adding electricity to the shop would be a big help, too! how far is the shop from the electrical panel in your house. You could bury an underground cable for about $1 a foot (and up) , and add a circuit just for the shop. It is more durable and carries more current than an extension cord.

PGJ