The bigger problem of working in your garage (fyi...I live in Minnesota) is cold molds. Cold molds just don't shoot well!
When I used to work in my garage (I finally had to give that up!), I used heating pads (like for your back) to lay my molds on to help warm them up...and keep them warm. Some people use an electric griddle...but I was always worried that I would forget to turn it off and burn the place down!
I would wrap the molds in the heating pads whenever I was doing something else (like trimming of the runner) so they would stay warm/hot. It's amazing how fast aluminum will cool down!