I have direct experience with in-floor heat. I personally ran the pex tubing on 12" centers in my 145' x 50' shop. I love it. I was going to use an outdoor wood stove to heat the boiler but I am very glad I decided to use propane instead. My heating bills are very reasonable.
I also bought the on-demand heater/boiler, manifold, pump, pressure tank, etc and did the install. I would not do it myself again. I would hire a professional and drink beer while he did all of that. It was like putting a puzzle together without knowing what the puzzle was supposed to look like. I did prevail but only after way too much time and way too many "F" bombs dropped.
I don't know of anyone around here that has the in-floor heat that isn't happy with it. My boiler is a Quietside. I bought it and all of the major components from some place in New York.
Sparkie is right....you better know exactly where you plan to place studwalls and plan accordingly with your pex loops. You hit a line then you are screwed. I did a 4" pour, suspepended the pex tube zip tied to the rebar 2" down from the surface and had everything planned precisely (bathroom, etc)so I could build studwalls. However, and fast foward 4 years to today, I have a need to build a mezzanine but I can't take the chance of bolting down by upright posts in fear of hitting a water line.
The Solution.......do a 6" pour and keep all of your rebar and tubing 4-5" below the surface. That's what others I know have done and that's what I should have done.....for the sake of being able to ramset nails or use anchorbolts without getting into the tubing.
At the time on was on a tight budget hence the 4" floor and doing it all myself. In hindsight, I should have found a way to do a deeper pour and/or hired someone to install the system.
My system actually has a baffle that allows me to heat water that goes to my shower and sink without robbing water that is in the closed loops that continously pumps throughout the floor.
