I have a detached 2-level, 2-car garage with no heat. Two cars are on the top level and on the lower level I have a wood shop. I also store my lawn tractor as well as other gas powered tools along with the fuel cans. The shop is approx. 24' x 28'. Is there a safe method of heating this lower level without removing the fuel cans or gas powered tools and the 2 cars above?