I use a portable propane heater to heat my shop, but I don't run it while I paint. I will run it prior to painting until everything is warmed good. When I get ready to paint, I unplug the heater, turn on the exhaust fan and open a window on the opposet end of the shop. As soon as I'm done and the shop has aired out, I shut off the fan, shut the window and start the heater to recover the heat lost from ventilation so the paint will cure properly. Depending on what paint is used, using medium or fast reducers and catalysts seems to help when it is cooler.
