Paul Cates - Henderson, KY
My previous workshop was an attached 2 car garage. 9' ceilings, 2 windows, and an uninsulated overhead aluminum door on 1 end which faced west (think wind blowing through the sides of the door). A 5600 watt portable contractor heater worked well for me, although on colder days I'd have to start it a few hours before I went into the shop. I purchased the heater at the link below. It's not the best organized site, but they have very good prices and selection.