Just built my new 30x40 pole barn and debating on radiant heat or not. I would like to keep it warm in the winter. My last barn had a woodburner which wasnt enough, then a salamander which really wasnt enough either and i hate the sound and smell! Would like to hear opinions by the way im in ohio and it gets in the negatives with the wind chill
Radiant heat or not
- Thread starter seths1985
- Start date
I have it mine and I'd do it again - love it. For sure insulate the slab and put in the tubes! I keep my 40x56x14 at 50 (thought I'd warm it up with a hanging heater but never do) in WI. Cost me about $80/month in natural gas. I've got another garage with a hanging heater and there's no comparison. Do the infloor!
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Randy in Maine
Well-known member
Questions first...
What kind of insulation do you have in the ceiling and walls? R Value?
How tight is your construction? Good windows? Good doors?
My point to make is thatto make a radiant heat build really "doable" you need to have a well insulated and tight building IMO.
What kind of insulation do you have in the ceiling and walls? R Value?
How tight is your construction? Good windows? Good doors?
My point to make is thatto make a radiant heat build really "doable" you need to have a well insulated and tight building IMO.
kuhner
Active member
Hey Seth,
I’m in Ohio also, along I70 near Cambridge.
I have a 40 x32 block garage and have radiant with a Seicor electric boiler. I love it.
Make sure to install the correct foam under your floor and around the edges.
I have AEP electric, keep it at 60, my electric bill averages $2.50 per day. From a low of the minimum they charge $45.00 month to about $175.00 when we have those stretches of near 0 degree. I figure that’s about a beer a day, I can afford that.
I have R20 on the outside of it covered in Dryvit, and R22 in attic.
I contacted a company called Blueridge Plumbing, found on the internet. They did all the layout and calculations for me. Recommend them if they are still around. Did install myself.
I’m in Ohio also, along I70 near Cambridge.
I have a 40 x32 block garage and have radiant with a Seicor electric boiler. I love it.
Make sure to install the correct foam under your floor and around the edges.
I have AEP electric, keep it at 60, my electric bill averages $2.50 per day. From a low of the minimum they charge $45.00 month to about $175.00 when we have those stretches of near 0 degree. I figure that’s about a beer a day, I can afford that.
I have R20 on the outside of it covered in Dryvit, and R22 in attic.
I contacted a company called Blueridge Plumbing, found on the internet. They did all the layout and calculations for me. Recommend them if they are still around. Did install myself.
kj_mustang
Well-known member
raspy
Well-known member
Definitely get the tubing in so you haven't burned that bridge. Radiant heat is the most comfortable heat there is and perfect for shops.
If you are in a really cold area insulate the slab edges and under the first couple of feet under the slab. 2" Blueboard works well for this. Use 1/2" PEX (5/8" OD). Hold the tubing back from the inside of the footings by 1-2 feet. Space the tubing and rebar at 12" on center and tie directly to the rebar with rebar ties. Make all loops about the same length and no more than about 300 feet. More loops of 200 feet is better.
Have the layout under pressure during the pour. All tube ends enter and exit the slab through 3/4" PVC electrical conduit sweep 90s. The simplest layout is a simple serpentine design with the hot supply feeding the lines closest to the perimeter.
An extra pass in front of doors, at 6" helps heat the room more evenly.
I don't recommend insulating under the entire slab unless you really want to. The insulation has to support the slab forever unless you make voids to get good ground support. The conduction in the middle of the slab to the ground just adds mass to the slab, but is not a loss path to the outside. More mass is good and shop slabs are usually massive to allow heavy machines and tractors, etc. Mine is 8" thick with no insulation except around the perimeter. I used #3 bar on 12" in both directions throughout the shop and house.
Your heat source can be as simple as a water heater or as complicated as a high efficiency boiler. Mine is thermal solar primary with oil backup in a cast iron boiler.
You will forever thank yourself if you install radiant.
If you are in a really cold area insulate the slab edges and under the first couple of feet under the slab. 2" Blueboard works well for this. Use 1/2" PEX (5/8" OD). Hold the tubing back from the inside of the footings by 1-2 feet. Space the tubing and rebar at 12" on center and tie directly to the rebar with rebar ties. Make all loops about the same length and no more than about 300 feet. More loops of 200 feet is better.
Have the layout under pressure during the pour. All tube ends enter and exit the slab through 3/4" PVC electrical conduit sweep 90s. The simplest layout is a simple serpentine design with the hot supply feeding the lines closest to the perimeter.
An extra pass in front of doors, at 6" helps heat the room more evenly.
I don't recommend insulating under the entire slab unless you really want to. The insulation has to support the slab forever unless you make voids to get good ground support. The conduction in the middle of the slab to the ground just adds mass to the slab, but is not a loss path to the outside. More mass is good and shop slabs are usually massive to allow heavy machines and tractors, etc. Mine is 8" thick with no insulation except around the perimeter. I used #3 bar on 12" in both directions throughout the shop and house.
Your heat source can be as simple as a water heater or as complicated as a high efficiency boiler. Mine is thermal solar primary with oil backup in a cast iron boiler.
You will forever thank yourself if you install radiant.
Stuart in MN
Well-known member
Radiant floor heat is really comfortable, but one thing to note is it works great if you want to keep the building at a constant temperature 24/7 all winter. On the other hand, if you only intend on turning on the heat now and then it may not be the best choice - it takes quite a while to bring the room up to temperature.
theoldwizard1
Well-known member
No, IT IS THE MOST COMFORTABLE HEAT YOU WILL EVER EXPERIENCE !
aunsafe2015
Well-known member
How expensive is it per month compared to a decently efficient gas furnace or one of the super high efficiency mini splits?
Mancino
Well-known member
Loopcad helps get you started with the layout. It's really not that daunting of a task. Once you get a system, it zooms right along.
Bottom line, you've spent a considerable amount on the building already I'd assume, because I built the same size. The extra money to add it, isn't going to make you broke. Just do the layout yourself...like I said, it's not that hard.
All in all, I have about $1600 into my materials. Manifold, tubing, insulation, etc. Just my opinion, but in the grand scheme of things, that's nothing when you look at the total you'll have into the building once its completely done.
If you want a better idea, check my build thread. You could almost copy my design if you want. 4 loops, approximately 275ft each. Doing 5 loops would be even easier.
Bottom line, you've spent a considerable amount on the building already I'd assume, because I built the same size. The extra money to add it, isn't going to make you broke. Just do the layout yourself...like I said, it's not that hard.
All in all, I have about $1600 into my materials. Manifold, tubing, insulation, etc. Just my opinion, but in the grand scheme of things, that's nothing when you look at the total you'll have into the building once its completely done.
If you want a better idea, check my build thread. You could almost copy my design if you want. 4 loops, approximately 275ft each. Doing 5 loops would be even easier.
Dagny
Well-known member
I install all types of heating systems. In floor is indeed the most comfortable but it is costly and not as efficient as everyone thinks. It's hard to insulate in front of the overhead doors. For everyday use I would consider a condensing gas furnace, nice eff. ratings an a lot quieter than hanging reznor or modine. also easier to add air.
Mancino
Well-known member
Dagny
Well-known member
If your system is pressurized get the o2 barrier
raspy
Well-known member
seths,
I'm not comfortable with foam supporting the slab forever. Insulation isn't necessary except around the perimeter and you can keep the heat back from the edges to prevent losses. You can also hold the heat back a ways from roll-up doors as you probably won't be lying on the floor in that area.
Oxygen barrier has nothing to do with whether the system is pressurized or not. It stops oxygen permeation into the system that will cause rusting of iron parts. You either must use equipment rated for domestic water, such as brass and stainless, or you must use oxygen barrier tubing. One other alternative is to use a good corrosion inhibitor, but the overwhelmingly best choice is to use oxygen barrier.
The slab does not have to be held at a constant temperature. I have an 8' thick slab and I warm it up when I want to work out there. It comes up slowly, but it only needs to be about 60-70 degrees to be comfortable for working. Once warm, it holds the heat well. I have been only adding heat to mine with solar. A few hours of solar each day and it is still nice in the morning. If there is no sun, the boiler will make it comfortable an a couple of hours. You can plan ahead or set the setback thermostat to come on before you arrive.
I'm not comfortable with foam supporting the slab forever. Insulation isn't necessary except around the perimeter and you can keep the heat back from the edges to prevent losses. You can also hold the heat back a ways from roll-up doors as you probably won't be lying on the floor in that area.
Oxygen barrier has nothing to do with whether the system is pressurized or not. It stops oxygen permeation into the system that will cause rusting of iron parts. You either must use equipment rated for domestic water, such as brass and stainless, or you must use oxygen barrier tubing. One other alternative is to use a good corrosion inhibitor, but the overwhelmingly best choice is to use oxygen barrier.
The slab does not have to be held at a constant temperature. I have an 8' thick slab and I warm it up when I want to work out there. It comes up slowly, but it only needs to be about 60-70 degrees to be comfortable for working. Once warm, it holds the heat well. I have been only adding heat to mine with solar. A few hours of solar each day and it is still nice in the morning. If there is no sun, the boiler will make it comfortable an a couple of hours. You can plan ahead or set the setback thermostat to come on before you arrive.
So did you put insulation under your slab?
finn
Well-known member
I have radiant in mine, and it’s great heat, but a waste of money if you aren’t out there every day.
A forced air system will be cheaper and works with a setback thermostat to keep the fuel bill under control.
Having lived with both forced air and radiant, I find forced air cheaper to run and the extra comfort of radiant not worth the extra cost.
Do insulate the slab, install glass and position the building to take advantage of radiant energy from the sun, and insulate the ceiling and walls well.
If I heat my other, non radiant, building daily with the wood stove or hanging gas heater, to keep the slab above freezing, it heats up quickly if I want to bring the temperature up.
I ended up installing a hanging heater in the shop with radiant floor heat also.
A forced air system will be cheaper and works with a setback thermostat to keep the fuel bill under control.
Having lived with both forced air and radiant, I find forced air cheaper to run and the extra comfort of radiant not worth the extra cost.
Do insulate the slab, install glass and position the building to take advantage of radiant energy from the sun, and insulate the ceiling and walls well.
If I heat my other, non radiant, building daily with the wood stove or hanging gas heater, to keep the slab above freezing, it heats up quickly if I want to bring the temperature up.
I ended up installing a hanging heater in the shop with radiant floor heat also.
lakeroadster
Well-known member
Radix2
Well-known member
Nope, oxygen barrier pex.
Normal drinking water pex is somewhat permeable to oxygen. If you use it for radiant heating, the constant supply of oxygen will cause iron based parts of the system ( boilers, pumps, valves, etc) to corrode.
If oxygen barrier pex is used, once the free oxygen in the hydronic water is used up, there is no oxygen left to cause corrosion and cast iron components are safe.
If non oxygen pipe is used in a radiant heating system, then only stainless, bronze, copper, plastic, (non corroding) components may be used.
Raisedonadeere
Well-known member
Care to share info on cost of LoopCad, I have to register, set up password etc before accessing pricing. Don't want to bother if it is major investment kind of stuff.
lakeroadster
Well-known member
Thanks Radix 
kj_mustang
Well-known member
I never bought it. Just used the trial. You have to be quick doing the design though as it only works a limited time.
Raisedonadeere
Well-known member
Thanks for sharing, I will plan accordingly. I did that once with HVAC Calc or some such soft ware (forget the name) to do a heating and cooling load evaluation on my house after realizing that all the HVAC guys around here sell you an oversized unit, the bigger is better school.
I decided to take matters into my own hands and used that software to do it and came up with one ton smaller system and had it installed. It has been perfect for 11 years, hottest summers and coldest winters, much more comfortable than the bigger units would have been and also less operating cost. Enough is enough and too much is nasty.
I paid a one time charge of $49 for a 90 day or 30 day use (again forget details) It was so useful I was tempted to just buy at the 3 or 4 hundred price and have it handy but everything gets obsolete so quickly with no update except to pay more money so I do not have it now.
Mancino
Well-known member
Randy in Maine
Well-known member
The 2" of rigid foam really doesn't settle or anything. Plenty fine unless you are bringing in big dump trucks or something. I am not. About $1 per square foot of 2" rigid foam. Do it under the whole slab.
Even though I am not out in my shop every day, my stuff that I don't want to freeze or rust is.
I find radiant heat (propane fired condensing boiler in the house with just hot water pumped out to the shop) to a very cost effective way to heat my shop (and my whole house), but my shop is really well insulated and has very low infiltration rates.
I like the fact that there is no standing pilot light or a flame in my shop.
I used about 1000 feet of 1/2" O2 barrier tubing on mt 40x28x12 SIPS garage and woodshop.
Even though I am not out in my shop every day, my stuff that I don't want to freeze or rust is.
I find radiant heat (propane fired condensing boiler in the house with just hot water pumped out to the shop) to a very cost effective way to heat my shop (and my whole house), but my shop is really well insulated and has very low infiltration rates.
I like the fact that there is no standing pilot light or a flame in my shop.
I used about 1000 feet of 1/2" O2 barrier tubing on mt 40x28x12 SIPS garage and woodshop.
slackdaddy1
Well-known member
Radiant floor in my last and current shop.
The last one was a uninsulated block shop, remarkably it worked out ok.
Current shop is a well insulated 22x32 shop.
I keep it at 50-55 deg all winter. I have a small "bottle top" propane heater, I turn it on when I am working out there and it quickly brings it upto 65 deg.
The beauty of it is- everything is "generally" already warm when I walk in, the propane just gets the air upto good "working" temp.
Best of both worlds, the electric boiler fired slab does not use much power keeping it at 50 deg, but I don't have to deal with cold slab, cold tools, etc.
Slack
The last one was a uninsulated block shop, remarkably it worked out ok.
Current shop is a well insulated 22x32 shop.
I keep it at 50-55 deg all winter. I have a small "bottle top" propane heater, I turn it on when I am working out there and it quickly brings it upto 65 deg.
The beauty of it is- everything is "generally" already warm when I walk in, the propane just gets the air upto good "working" temp.
Best of both worlds, the electric boiler fired slab does not use much power keeping it at 50 deg, but I don't have to deal with cold slab, cold tools, etc.
Slack
raspy
Well-known member
No. No need for it.
TheEquineFencer
Well-known member
Radiant for sure. You can have the doors open and close them and in a matter of seconds it seems it's warm again. I'd wrap the inside in Foil/Foam/Foil after you put the foam board in if I had the $$$. It'll add some R value plus reflect light and make the inside air tight.
I had a pole barn and just had F/F/F in it on the roof and walls and was amazed the difference it made just sealing the building up.
I had a pole barn and just had F/F/F in it on the roof and walls and was amazed the difference it made just sealing the building up.
I chose to not do radiant in my shop build. Yes it is great heat, but spendy. I can buy everything wholesale and get the boiler free and have done many radiant installs over the years and still didn't do it. I used the Rinnai EX38 in my shop and it was simple, efficient, cost effective and I am very comfortable with it. It is worth a look.
finn
Well-known member
Ordered propane today. First refill since I replaced the oil boiler with a 95% condensing boiler. Thirty days and it will take about 120 gallons, going by the tank gage.
Temp in the 32x75x16 shop has been about 57 degrees, and the 16x16x8 office at 65 degrees.
At $2.00/gallon, that's about $240/month.
Looks like next year I will go back to using the radiant heat to maintain a room temperature in the low forties and use the Beacon Morris hanging heater to bring the temperature up while the shop is occupied.
Temp in the 32x75x16 shop has been about 57 degrees, and the 16x16x8 office at 65 degrees.
At $2.00/gallon, that's about $240/month.
Looks like next year I will go back to using the radiant heat to maintain a room temperature in the low forties and use the Beacon Morris hanging heater to bring the temperature up while the shop is occupied.
rburke65
Well-known member
Lots of info on this forum and on Google. Suppliers of tubing and supplies offer free info.
mygarageone
Well-known member
I keep hearing you don't need to insulate the floor except around the perimeter , I don't know of any heating designer who would recommend this , I saw only one project in several years with no floor insulation . It was an engineered job , that building cost the owner Hugh gas bllls because of it. The engineer never considered the water table ! It was high and became a heat sucker , the water was sucking the heat right out of the ground . They sued the engineer and won. So if you decide not to insulate the floor be sure you don't have a high water table. But for the small amount of insulation cost , put it down .
raspy
Well-known member
Radiant in a basement is not a good idea if the floor is at or below the water table. There are also losses around the perimeter if the slab is warm around it's edge.
Assuming the ground is dry underneath, the heat is held back from the edge and there is slab edge insulation, there is no need for insulation underneath.
The heat in the lab wil conduct down, but only so far. This affect is the same as a thicker slab. But remember, insulation only slow heat flow, so there will still be some down conduction. The distance this conduction goes is not infinite.
Another concern is the slab being supported forever by the insulation. Some insulation has a strong resistance to compressing initially, but for how long? Can we be sure it will not breakdown over time and settle? One of the obvious bad choices would be bubble wrap. Another would be open cell isocyanerate that is not water proof. I've seen both being used.
Just because insulation may be cheap, is not a reason to use it. It should be used when and where it will do the most good in a relaibale way. If you are convinced there will be heat loss from below, define how that will happen.
Assuming the ground is dry underneath, the heat is held back from the edge and there is slab edge insulation, there is no need for insulation underneath.
The heat in the lab wil conduct down, but only so far. This affect is the same as a thicker slab. But remember, insulation only slow heat flow, so there will still be some down conduction. The distance this conduction goes is not infinite.
Another concern is the slab being supported forever by the insulation. Some insulation has a strong resistance to compressing initially, but for how long? Can we be sure it will not breakdown over time and settle? One of the obvious bad choices would be bubble wrap. Another would be open cell isocyanerate that is not water proof. I've seen both being used.
Just because insulation may be cheap, is not a reason to use it. It should be used when and where it will do the most good in a relaibale way. If you are convinced there will be heat loss from below, define how that will happen.
I have been in a 30x50x16 that had no insulation except a reflective material, then pex tied to rebar. His shop always felt pretty nice even on real cold days. Thats why im kinda with raspy, im sure it helps but to me seems like the cons outweigh the pros, atleast in my way of thinking
Randy in Maine
Well-known member
Maybe in Nevada you don't need insualtion, but not here where it can get cold.
raspy
Well-known member
Insulation prevents heat loss, or slows it. Can you explain where the heat loss is underneath a slab? Not the edges, not the walls or the ceiling. Underneath the slab when it is on dry ground?
What is the mechanism and where does it go? I can see the dirt adding to the mass that must be heated, to a certain extent, but is that energy lost? To where?
Additional mass isn't necessarily a bad thing as it stabilizes the temp. This increases the comfort and reduces system cycling. But it could reduce response time from a cold start.
I'm not telling people not to use it, I'm saying use it where it will produce a benefit, or where the benefit outweighs the negatives.
It gets cold in Nevada too. That's why I have 24" of blown in insulation in the attic, and walls full of it. It's why my radiant slab is insulated all around the edge with 2" Blueboard and the heat is held back from the walls inside. It's also why I went to the trouble to install thermal solar to carry the majority of the heating load. Fortunalely, we are almost always sunny.
Dagny
Well-known member
Yes I think where you live makes a difference. Here in the great white north you need insulation. I would also like to say I think I am correct on if your system isn't pressurized and is open to the atmosphere o2 barrier is a waste of money as your system will keep picking up oxygen from the air. Most outdoor wood stoves are this way. If your system is pressurized it is isolated from the atmosphere. and only the initial oxygen will react with the iron parts of your systen.