Installing Radiant in my garage, I have a bunch of ? head is spinning

   / Installing Radiant in my garage, I have a bunch of ? head is spinning #1  

JOE G

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Aug 28, 2012
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Eastern NY
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Hi, I am putting up a 28 X 28 Garage, first floor will have 10 Ft ceilings, the Second floor is just for storage and will have 8 Ft Ceilings, The first floor ceiling will be insulated.

I am getting a 1000 Ft roll of 1/2 In tubing and will be putting down the insulating tarp below it.

I am not adding the actual heat source yet, prob will do that next year but want to get the pipes run now.

I won't have a full time water source out thee for a while I can reach it with a hose to charge the system.

What kind of heater should I use? I have choice of electric and LP, I am unsure if I should use a 40 or 50 Gal water heater or a Instant Heater Elec or LP?

Thoughts? Thanks

P.S is Radiant even the way to go, I plan to keep the heat around 50 Deg I don't want to spend a fortune to heat the place, Just want to keep stuff from freezing.

If I was going to be out there for a while how long would it take to raise from 50 Deg to say 65 ot 70? if out side temp say was around 30 Deg.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #2  
How about solar? Solar heating hot water is pretty efficient these days and the thermal mass of the slab will keep the garage toasty.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning
  • Thread Starter
#3  
Solar Would be nice option I guess don't know much about it.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #4  
Since you haven't built it yet, earthberm it. It will stay above freezing whether you have power or not.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #5  
this is my suggestions,

First I would put in an antifreeze solution,
I not sure you will get the efficiency from a hot water heater you want, I would really suggest the proper boiler,

If you said it I am not seeing it, my guess is your putting this in the concrete floor,
one of the other problems is rapid heat adjustment will not be very easy, as your heating a mass, and the mass will heat slowly, and then the mass heats the air,

but if the mass is warm it will feel more comfortable than the air warm and the mass cold,

you may want some type of air heater to rapidly warm the air,

as far as the fuel type, I would do a little study to see what system would be the lower cost,

but a solar panel may be a consideration, (even a DIY unit and a thermostat and circulating motor) maybe able to do a lot of the heating
situate it to the south, (roof or wall) basically an insulated box, with a black sheet of metal in the middle, with tubing on it to transfer the heat, to a fluid with a thermostat in the box to run a circulation pump when the panel is warm enough to help it kicks on and heats the floor, with just the power of a small pump,

the day time heating needs and the floor holding mass, (the panel, may heat the majority of the needs of the building), some would depend on the size of the solar panel,

I would most likely use propane if it was my building,
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #6  
summary...Glycol solution....boiler wood/fired or gas fired......keep mass on fairly high heat setting...takes a long time to go from just above freezing to nice warm temperature.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #7  
I am getting ready to build a 36x40 garage, with 14 ft ceilings. Depending on how much work you want to put into it, you might consider other options. One would be a waste oil furnace, obviously you have to get your fuel, but there are probably enough places around your town that would gladly give it to you versus paying to have it hauled away. You can get them in just a blower type furnace, or in a boiler system.

The hot water tank idea, while it will work, it won't do real well in severely cold climates. Now that being said, I would say away from the instant on type of heater. Most likely in the winter time, the heater is going to run 24/7 or nearly. Depending on the price of LP, it would probably be the better option. Gas is going to heat faster if you go with a hot water tank.

The amount of time for it to raise the temps, it will take some time, probably a few hours. However, talking to individuals that have radiant heating systems in their shops/garages, they all claim that they actually leave the temp turned down between 60 and 65 and claim that it is almost too warm still.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #8  
Hi, I am putting up a 28 X 28 Garage, first floor will have 10 Ft ceilings, the Second floor is just for storage and will have 8 Ft Ceilings, The first floor ceiling will be insulated.

I am getting a 1000 Ft roll of 1/2 In tubing and will be putting down the insulating tarp below it.

I am not adding the actual heat source yet, prob will do that next year but want to get the pipes run now.

I won't have a full time water source out thee for a while I can reach it with a hose to charge the system.

What kind of heater should I use? I have choice of electric and LP, I am unsure if I should use a 40 or 50 Gal water heater or a Instant Heater Elec or LP?

Thoughts? Thanks

P.S is Radiant even the way to go, I plan to keep the heat around 50 Deg I don't want to spend a fortune to heat the place, Just want to keep stuff from freezing.

If I was going to be out there for a while how long would it take to raise from 50 Deg to say 65 ot 70? if out side temp say was around 30 Deg.

Good start, you are asking all the right questions.
Divide your tubing into four equal length runs, and interlace them into the floor, so if one is eventually compromised with a leak you can simply block it and run the other three. About 250 feet is correct per run, plus or minus but keep them equal within a few percent.
LP is cheaper than electric in most cases.
A standard water heater should be enough for your application. A power vented one is a bit better cause it makes more heat and because its easier to plumb the exhaust thru the wall in PVC. I have use this method since 1997 in a 28 x 38 in southern Minnesota. It works great. I keep the air temp at 50 and thats enough if you are wearing a light jacket. If I know ahead of time I will be spending all weekend in there, I turn it up from 50 to 60 and it will stabilize in 4-5 hours.
All the above recommendations are based on the assumption that you are going to put insulation under the slab. At least 2 inches of extruded polystyrene is my recommendation, and current code in my area.
My building also does not have water supply. Not a problem, once the system is charged it is maintenance free if it does not leak anywhere.
I do not run any anti freeze. If power goes out, it would take over a day to freeze the water in tubing in the floor, due to the thermal mass. So, my power-out backup plan is (and never had to be used) to drain the water heater onto the floor and let it go down the drain, and then blow out the floor lines with compressed air, which is available at all times in a 60 gallon tank charged to 125 psi right next to the heat system.
If you go with a standing water tank heater, be sure to factor in that extra 40 gallons in the system total, and size the expansion tank accordingly. I'd suggest something about 4-5 gallons size pressure tank (half that is air, half is water), with 1000 feet of 1/2 inch tubing (~9 gallons) and a 40 gallon water heater.
You will love hydronic radiant floor heat. It is comportable (at lower temps that forced air would be), simple, cheap to operate, and fast to recover if a door is opened for a few minutes. Your dogs will also love it.
 
   / Installing Radiant in my garage, I have a bunch of ? head is spinning #9  
Be sure to isolate outside wall/footings from the slab,with pink foam board, also put it under the slab. Floor heat is so efficient that you may leave it up more, say 60 deg. My neighbor heats a 38'x70' pole building with an electric, on demand, water heater. It has 2 zones, and is divided, living space and shop, he is very happy with it.

Dave
 
 
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