A portable propane heater is going to fit your needs best and using a 20 lb cylinder will be more cost efficent, last longer and maybe more easy to obtain. I use one in my shop and it works great. Take it from a retired Firefighter/Specialist it is safe and only a few precautions to take. First, as far as dust, if you are only scrolling and minor wood working needed for scrolling dust is not really an issue. Using a dust collection system is more than adequate. The dust needed for an explosion or problem would be as thick as a cloud or fog. You wouldn't be able to breath (or have a really had time) it would be so thick. Second, oxygen etc. The propane heater would go out before it consumed all the oxygen (a garage is usually not air tight). A portable propane heater uses about the same amount of oxygen as a couple of people. Carbon Monoxide is what you need to look out for. Just buy two Carbon Monoxide Detectors (not expensive) and you can take them with the heater when you move. Put one in the garage and one inside to keep you safe. Most new portable propane heaters burn very efficent. Kerosene on the other had is not as efficent and the smell you have to put up with ( Kerosene has open flames). Now painting etc. here is what you do. Warm the garage up real good 80 degrees or so. Turn off the heater... Open flames is the problem. (Note, an electric heater can cause an explosion if the mixture is right) Due your painting etc. Watch the temperature. Most paints due well above 50 degrees. When the temp drops to around 50 degrees turn on the heater, this should have been more than enough time for any fumes to have disapated and be safe. Now you can let you work finish drying. Hope this helps.
