heating your garage

I haven't heard of heat damaging a cars paint. Keeping the garage around 10-15 degrees should be fine.

One of the best ways, to exclude all the heaters and wires, is to put in-slab heating. Hot water piped through the concrete in the garage. Takes a little longer to kick in (about 4 hours in my basement) but is great because you don't need an extra furnace.

 

In-Slab heating?

http://www.midnightconstruction.com/images/photos/295_Rock%20Retaining%20Wall%20016.jpg

That is what's laid down on the floor, then concrete is poored overtop.

A cut-away look at it the finished product. http://www.fha.com.au/images/slabX.gif

The pipes have hot-water pushed through them, thus heating up the floor. It's all controlled by a thermostat.

 

Solid car,
I have an older home and it was a concern for my cars as well. For many years now I have used plywood on the floor, with a sheet of plastic and a big piece of carpet I had. This will stop moisture from rising to the undercariage.

As for the heat, I have two small electric heaters, one in the front of the car, and one in the back at opposite ends. This helps ensure some constant heat flow from the back to the front. I have not had a problem with them running throughout the winter.(Get the ones with an emergency shut off in case they overheat). Ive been doing this for the past six years, and the temp in very cold temps has never hit below 5. The main goal to avoid the moisture. Worked perfect for me. Good luck.

If you could insulate your garage that would also help.

 

just an insulated garage works pretty well for us
but we also drive through the winter the car gets to warm up through there

 

Inferad tube heater works well. This will heat up the concrete floor and objects in your garage and radiant the heat back out. Low operating costs and heats up wonderfull.