I live in the Seattle area. I have a 2.5 car garage which I am developing
into a woodworking shop. There will be 1 car parked there also. Although
it generally doesn't get quite as cold here as it does in some other parts
of the country, it gets cold ENOUGH at times during winter to keep me out of
the shop. I'd like to add some source of heat. The shop has 2 wooden
single car garage doors, reasonably well sealed, unheated living space
about, 2 78" x 48" double pane windows, an 8' ceiling, and drywall on all
walls. Walls are currently uninsulated, but adding blown in insulation
should be pretty easy. To start, I am considering either an electric
heater, such as this: http://www.heater-home.com/product/G73.aspx. Although
the specs on this one say up to 500 sq', the climate here's not that cold,
plus all I really want it to do is get the space up to 55-60. The downside
is the cost of electricity to run the unit.

Another option seems to be a non-vented propane heater (we do not have
natural gas) like this one:
http://www.heatershop.com/garage_heater_gp30t.html Pretty cheap, but I'd
have to buy a 100# propane tank to go with it which adds cost, though
operation is probably a lot less than the electric type. But I'm not sure
I'm totally comfortable with using a non-vented propane heater.

I'm sure there are people here with experience heating a workshop. Any
suggestions appreciated.

TIA

Dan