radiant heat

I have put in thousands of feet of infloor radiant heat and in my opinion there is no better heat. It is slow to heat up but when it is warm everything is warm. You can open the overhead door, run the the car in or out, close the door and in a matter of minutes it is the same temp it was before you open the door, and this is North Dakota where it gets cold. I have put it in an airplane hanger where the door is 50+ feet wide with the same results. I tell anyone building a garage to put the pipe in the floor even if you can not afford the boiler. That way it is there for the future. Even if you don't put down insulation put the pipe in the floor. I will never build a garage without it.

As far as a garage installing 2 feet spacing with 5/8" pipe works fine. Just keep your loops under 300 feet. You can go longer loops but then you need a larger pump which cost twice as much. More loops tied in parallel will give you more security like 67dart273 and of course you need antifreeze protection. Just like a car it will heat/cool better with antfreeze.

One other thing is radiant heat works best when it is on constantly. As said earlier it is slow to heat up. I have a hydronic hanging heater to heat it up quick or when I am only out for a few hour and it works great. As far as brands I know kytec out of Canada used to be the best, I put allot of it in, I don't know if it around anymore. I used aquatherm by zurn in my garage and it worked fine. the stuff menards sells seems kind of cheap but I have not used it. You want something that is easy to bend and is not brittle. I always put 100 psi on it when I pour it so if it gets hit by someone and leaks you will know it.