I currently heat my shop with an 80,000 btu propane ceiling hung heater. It is a little under sized for the space but it takes the chill out and can still make the shop comfortable on pretty cold days. Plus, it was a freeby!
I put the radiant tubes in the floor before it was poured but have not gotten around to finishing the system. I know that this type of heating takes time to warm up and once there it works better if kept on, obviously not ideal unless you are in your shop consistently or often. From everything I have read, you don't have to set the t-stat real warm to make the shop comfortable since everything from the floor up is essentially the same temp. In my shop at work, there is a condensate return tank for the boiler located in another part of the building. There are several return lines in the floor in the shop that run to this tank. Now that's a hot floor. Too hot to work on for very long.
My first time experiencing radiant heat, I was visiting a friend in Cape Cod. The night I got there it was 11 degrees out. He said grab a beer and we will go sit out on the sun porch. I'm thinking its got to be freezing out there. It had 3 sides glass but it was unbelievable how comfortable it was out there.
I am looking forward to hooking mine up one of these days.
