radiant heat

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dartnfish

dartnfish

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trying to find the money to insulate and put pex tubing in the floor of my new shop. i was just curious what everyone has used and how well it worked. not wanting to go cheap but i am tying to save a little money in the process. the insulation being my biggest question. been looking into creteheat but my goodness that stuff is expensive but very easy to work with. i helped a guy down the road do his basement and that is what he used.
just looking for some advice outside the boiler dealer.
Thanks-
Shawn
 
I don't know anything about creteheat.

Floor based radiant is great stuff, but it's "slow." This is part of what makes it great for an occupied space, as it creates a nice even heat, and your feet stay warm.

The other problem with liquid radiant heat, other than "slow", especially in an outbuilding, is freeze protection. You either have to insure the thing is actually working full time, or use an antifreeze mixture in the boiler

If I had a shop I would not be able to afford to keep it warm, I would want a quicker system. That means conventional "oversized" forced air, so you can wake up on a Sat morn, spend a little time "shooting heat" into the shop and get to work.

I would think what you do is going to depend on cost per btu of heat options in your area. You have nat gas? Mostly oil? High elect. rates? That might dictate what you do for a system.
 
What type of construction is it? If conventional framing, 2x4 or 2x6 stud walls with insulation and drywall, and an insulated attic, a warm air furnace type of heater MIGHT work okay.

but for most shops, it will be disappointing, as most shops tend to have lots of air leaks. And the high ceilings contribute to the problem.

Radiant heat is exactly what you want, but maybe not the 'in floor' radiant heat. As mentioned by 67dart273, it takes a LONG time to raise the temp. In Your home, it is generally less of a problem, since you normally want it to be comfortable all the time. Do you want your shop heated 24/7?

Airplane hangars are heated with radiant heat. Enormous warm air heaters wouldn't have a chance of doing it, cause warm air rises. Radiant heat can be directed sideways, straight up or down, and is not 'lost' with the movement of warm air which travels upwards.

I would consider radiant ceiling heat if I were you. You might want to check it out.
 
BTW, is your slab already poured? If so, 'in floor' radiant heat is out of the question. You would have to have poured your slab over polystyrene, then do the pex or whatever, and then the lightweight concrete over that. But I would NEVER personally put 'in floor' heat in a shop. Radiant heat, yes.
 
I put radiant in my home, all pex, in the concrete basement, in the two main floors with stapled metal plates. Its heated by regular hot water heaters, not a boiler. Shoot me a PM if you have questions about that type of install.
 
the most expensive operating part of the radiant in-floor heat is the first few hours after you raise the temp. If you don't mind keeping it at a constant temp, and your shop is pretty airtight, then it will be pretty efficient as far as heat goes. Also, any shop tools (press, drill press, lathe, etc... won't rust!
I have 2x6 construction, stick framed barn roof, with regular R-19 in the walls and R-30 in the ceilings. I use a vermont castings wood stove that is meant to heat about 2400 sq ft. Floor space in my shop is 1,000 and I can close off about 250 of that so it gets warm pretty quick (unless it is during the middle of winter and I have not been out there for a few weeks).
 
I had it installed by some complete hacks. Complete waste of money thanks to them. If I could do it over again I do not know if I would bother....I like our pellet stoves. Enough so that when i build my working garage some year that is going to be what I put in it....
 
the floor is not poured yet and the outdoor wood boiler is installed and hooked to my house, main line is ran into the barn (pole barn) heated section will be 40 x 50 so i don't want to but a furnace in the corner and be cold at the other. 12' ceilings so all my heat will end up there anyway. thats why i want to start with heat at the floor. only cost is going to be the insulation and pex tubing so i was looking for input on that.
 
Google Tom Tesmar or I can get his contact info later. He sells high quality pex and other radiant materials and consults on installs. He's the best in the business.
You don't need insulation under the slab, just a thermal break between slab and outer foundation.
 
Idaho said:
Google Tom Tesmar or I can get his contact info later. He sells high quality pex and other radiant materials and consults on installs. He's the best in the business.
You don't need insulation under the slab, just a thermal break between slab and outer foundation.
Click to expand...

that sounds like a savings to me!! PM me his info if you get time.
Thanks-
Shawn
 
dartnfish said:
t outdoor wood boiler is installed .
Click to expand...

With one of those I would absoLUTEly take precautions to protect against loop freezing, or use antifreeze in the loop

If you can afford it, I would also consider stringing a "spare loop." Might sound expensive, ----until you need to chisel up the floor in a few years
 
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.
 
swifty said:
.............I always put 100 psi on it when I pour it so if it gets hit by someone and leaks you will know it.
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LOL. Ya mean it's not 'sposed ta bubble up like that?

Thats a good idea.
 
67Dart273 said:
LOL. Ya mean it's not 'sposed ta bubble up like that?

Thats a good idea.
Click to expand...

I had a cement truck driver hit the pipe with the chute once. Put a splice in, which is not the best, and finished the job. Still holding and saved alot of headache.
 
Insulation under the slab is imperative! Don't pour your concrete without checking into this. Yes, a thermal break at the perimeter is important too.
 
I have a 40'w x 63'L shop built w post frame construction and I put in-floor heat. I used 1/2" pex tubing in concrete that I installed myself. Then I hooked up to circulating system and electric boiler set on off peak rates controller. Here in ND the power company powers off peak only 12 hrs a day in winter. The system works great, I set at 55 or 60 degree and it keeps it constant all winter. I work in flannel shirt or sweatshirt and am comfy. I may convert it to natural gas boiler in future cause power rates have gone up. The walls have R19 and ceiling R30. On the floor insulation I used 2" foamboard on edge and 1.5" from edge inward 4 ft. The circulating system is a Hydra-Smart panel purchased from Menards. It has been trouble free for 4 years. If you have questions send PM. I have pix if you need to see something.
 
we just did our 36x60 with in floor. I believe it was 2" high density poly? insulation under it along with a couple vapor barriers. haven't finished the boiler install yet.
hopefully in the next month or so. cant wait a neighbor had it in his shop. it was so nice when you crawled under the car to work on it and the concrete wasn't cold as ice.
we plan on a wood burner to for quick temperature changes. we plan on leaving it at 50 ish all winter.
 
I put radiant in my 40 x60 shop and love it. Perimeter insulation between the slab and foundation walls is critical this is the biggest heat loss on the slab.I used a product called insul- tarp under the slab. It comes in 12 ft wide rolls and you just roll it out. I took pictures of the loops before the slab was poured for future reference. I also dug out a deeper area for footings for the lift and measured it out so I did not hit any tubing when I put it in. I wish I had a wood boiler instead of oil. Good luck!
 
I installed radiant floor heat in my shop. 3456 sq feet. I used 2" foam board under the concrete , and on the sides to break from the foundation walls. I used 3/4" pex, six loops, mine are probably a little long. We'll insulated walls, 1" spray foam with an r19 batt over that. R30 in the 15' high ceiling. I am using a natural gas takagi water heater. Keep it at 58 degrees, all winter. Most expensive most so far was $60. I didn't think that was too bad, plus I love not working in the cold.
 
Is it true that concrete, like stone or rock or brick will retain heat also? If so, the main cost would be in heating it up first like someone else said?
 
Louie70Dart said:
Is it true that concrete, like stone or rock or brick will retain heat also? If so, the main cost would be in heating it up first like someone else said?
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There are no free rides The only thing a great big heat sink like a concrete slab does, is to EVEN out heat over a long period of time, it doesn't save you any money or heat.

And, if the slab conducts a lot of heat into the ground, it's a loser

The parallel is cutting one end off your blanket and sewing onto the other end to make it longer. The slab might retain heat, and help "heat" the shop after the boiler is shut down, but IT ALSO took more heat to get it up to temp in the first place
 
It's been awhile since I've installed radiant heat in concrete. Back in the mid 90's we used a product called "Infloor" and we set a base then installed slab insulation on top before we laid the heat loops. After the loops were down we poured the floor. As mentioned in a previous post we also pressurized the loops while we poured just in case.

Like I said, it's been a long time since I worked the trade and I don't know if things have change that much. Keep doing your homework and have a good design. Don't forget to find a good spot for the supply manifold setup and valves .

I remember one install we rolled this in a guys driveway just because he didn't want to shovel. LOL A Plastic surgeon with more money than he knew what to do with.

If I could, I would do this in a hot minute. Good luck with the project.

AlV
 
got some good info froma dealer of CRETE HEAT insulation last week. it is 2" thick and has rosets molded into the top side of it to hold the pex in place. they are layed out every 4" so i guy can route his lines furter apart or closer together. he suggested 5 layer 1/2" tubing that has an oxygen barrier 12" apart. i will need 7 300' loops and i'm going to centralize my manifold. he said do three loops in the front and three in the back then fill the center in with the 7th loop. seemed like he really knew his stuff. need a pump to circulate at 1gpm and a plate to regulate the water down to 100degres or a little less. i guess you dont want anything over 100. Also antifreeze. have the money saved up (more than i wanted to) going to plan on install as soon as the weather breaks. this fella even said he would deliver the material and make sure it was installed corecttly! Only have one shot do it right. i'll keep you posted and take pics.
 
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