I have in floor heat in my slab. I highly recomend it. Last years heat bill in northern Iowa was $43. Very important that you create a insulation bowl so to speak. I have 2" pink high density foam on the bottom and up to the pour line or concrete height on all 4 sides. I installed the plastic heat tubing in 3 zones. ( garage is 24X36). also important is to keep the zones nearly equal in length. This keeps one from getting hotter than the others. I ran the tubing about 12-14" apart and fastened them to the foam. Poured concrete over the top. I heat the water with a small boiler hanging on the wall. The name of the boiler is Munchkin. It will vary the burner output to match the water temp drop of the circulating water. Fill lines with antifreez ( I used RV for environmental concerns) and away you go. I have heard from others who used a water heater. The problem they had with those was needing to create a control situation that would turn the heater on and off or leave on and it will keep the loops and tank at a set temp. You will also have and additional water in tank. You will need to control a circulating pump also. The boiler idea has all the controling incorperated and is operated from a wall therm. Set it and forget it.
I also have floor heat and love it. The best part is that all your equipment stays at temp also, no more cold tools and parts. I keep mine set at a temp that is chilly until you get to working and then its perfect. I didn't insulate under my floor but the coils are sitting on a sand base and my slab is eight inches thick. I'm using a boiler and it comes on only about every two hours and then for a short time.
I have an overhead heater that I use when I bring in a cold project car to help warm the air back up in the shop quicker as my thermostat is near the outside door. I located it about 30 inches above the floor but don't know if that's the best plan.
I believe the key to a great shop is to insulate it well, I used 8 inch R-30 fiberglass and it is also surprisingly quiet. In the summer I don't even use an air conditioner, I keep the doors closed and use a dehumidifier.
Type in Munchkin Boilers on the internet. There are many compact boilers out there. Even electric if you dont have a fuel source. My came from a plumber who shares my shop space for his Nova. Go to my pics
Not sure if there is still an interest.
Radient heat if it's properly installed,will due the job.
1 cheep heat,gas or propane
2 less heat loss,lower cost of heating
3 warms the concrete floor,and objects in the garage
4 less heat loss when opening the garage doors
5 the radient heater should be the 8ft double tubed heater
That is the system I am currently installing in my shop. I am just now to the point of pouring the concrete.
I put 8 inches of sand base down, and compacted it, then two layers of poly vapor barrier. I topped that with 5 inches of hi-density foam, and laid out the re-bar.
Then following directions on the net I got the right kind of PEX tubing and laid it out so that all around the perimeter the lines are 6 inches apart, and are one foot apart everywhere else. I used half-inch ID pex, and no one line exceeds 150 ft. in length. (a lot of lines for my 40 X 60 shop!) Then I added an inch of hi-density foam between the actual floor and the foundation walls (Why try to heat the foundation?) and between the "inside" floor and the "outside driveway" (again, why have heat transfer to the driveway - its the shop you are heating, not the whole world!)
Now my next steps (this week) will be filling the lines with anti-freeze and pressure-testing them (individually) to 100 psi to check for any leaks. Then cap them all off (leaving them full of anti-freeze) and pour the concrete.
Last step will be installing manifolds to distribute heated fluids and collect the cooler returning fluids, the add in a boiler/heater whatever and a pump to keep things circulating, all controlled by thermostats in each of the three zones.
If you are going to do the work yourself, the best instructions I have ever found are at:
Just as a follow up - if you are using half inch PEX as the tubing for the in-floor heating, be advised that every hundred feet of tubing needs just under one gallon of fluid for filling. I just filled and pressure-tested mine. I have approx 2600 feet of tubing (2400 sq ft shop) and I used 24 gallons of 50/50 antifreeze/water mix to fill all the tubing. Pressure-tested to 125 psi, and its all good to go.
Well - what I did was to start off by thinking that half inch is not very big, so I got 5 gallons of Prestone (I figured I have some left over!) and then mixed the first gallon in a bucket half and half with water - yielding 2 gallons total of fluid.
Then, using a drill-powered pump I pumped the first line full. When it started coming out the other end, I let it run back into the bucket and kept it going for another couple of minutes. Then I capped both ends of that loop, and moved on to the next one. But the bucket was nearly empty, so I dumped in another gallon of Prestone and another gallon of water, hooked up the drill pump and.....
After a while I went back to the store and got another 7 gallons of Prestone and kept up the same procedure.
Out of 24 gallons total of fluid, I have about a half gallon left, all the lines are full, and I have some 2600 feet of line in place.
Then I crimp-sealed the (return) ends of the lines, crimp-sealed (with an adapter) and air-compressor end to a 3 foot piece of pex and used a "shark-bite" connector to join the free end of the 3-fot piece to the still uncrimped end of my floor line. Hooked 125 PSI to it, left it for 10 minutes and checked for leaks. No leaks. Release the sharkbite from the end of the floo line and re-seal that. Hook the sharkbite to the next loop and repeat the 125 PSI test.
Repeat for all 13 loops.
Yes, there may be some air remaining in the lines, but the air/water separator that will go between the return manifolds and the heater will trap that, and allow for fluids to be topped up