Hi guys haven't been on here in many years.I need some help making decision.I'm getting ready to pour floor.I have been planning to use radiant heat in floor. 2 inch foam insulation specifically, I think it is 250 Owens corning.Have design manuals from Zurn on how to layout tubing.Now I am questioning myself on quality of heat versus expense. I think I should just do it.A guy I know said his cousin has cold spots so he added wall heaters. I've got on different webs looking at ideas,including insulation types.So what explained seems to be the most cost efficient. You guys have any experience?
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Heating 30X60 garage, questions
- Thread starter SDBOB1
- Start date
Pythong
Well-known member
I don't have my infloor hooked up yet as im still in the building stage but here is how i looked at it when building my garage.
You have one shot to do anything with the slab, i dropped $10,000 in concrete for my garage and didn't want any regrets - put 2" styro under the slab and ran 2000' of pex. One chance to do this and it only set me back ~$3000 to do.
I can't see why you would have cold spots if you did your loops proper: Equal length and adiqate spacing. Keep the spacing close for perimeter walls and maybe a little closer for your overhead door openings.
eg. Perimeter had a run 6" and 12" off the walls, and then the remaining of the garage was every 12". The overhead doors i did 6",12", & 18" then proceeded to do every 12".
I don't have insulation/heat in my garage yet but ive heard/read nothing but good things about it.
Like i said, you have one shot to do it and IMO its pretty cheap compared to the rest of the build.
You have one shot to do anything with the slab, i dropped $10,000 in concrete for my garage and didn't want any regrets - put 2" styro under the slab and ran 2000' of pex. One chance to do this and it only set me back ~$3000 to do.
I can't see why you would have cold spots if you did your loops proper: Equal length and adiqate spacing. Keep the spacing close for perimeter walls and maybe a little closer for your overhead door openings.
eg. Perimeter had a run 6" and 12" off the walls, and then the remaining of the garage was every 12". The overhead doors i did 6",12", & 18" then proceeded to do every 12".
I don't have insulation/heat in my garage yet but ive heard/read nothing but good things about it.
Like i said, you have one shot to do it and IMO its pretty cheap compared to the rest of the build.
Randy in Maine
Well-known member
1800 square feet of garage = 6 x 300 feet of 1/2 pex (12" on center) loops going to and from a 6 way manifold that will likely feed from a 3/4" pex to the boiler. $700 (I use the builder in my house since it was already paid for) and just pump hot water out there and cold water back).
Plan on about $1 per square feet for the 2" of insulation. $1800.
If you are thinking about installing a lift, ask them for how big of a circle around the posts where they don't want to see any tubing. Usually it is about 3'.
Plan on about $1 per square feet for the 2" of insulation. $1800.
If you are thinking about installing a lift, ask them for how big of a circle around the posts where they don't want to see any tubing. Usually it is about 3'.
Thanks guys. I just wondered if anyone had cold spots. 1/2" pex. 3 zones. I noticed on another post some one placing pex on foam.I read closer to surface of concrete is better,actually was going to fasten to wire mesh. I almost sold on 4 post lift versus 2 post,versatility. Would I need to be concerned about placement on top concrete over pex? I'm using 4000psi concrete. Thanks.
TedBrown
New member
Thanks guys. I just wondered if anyone had cold spots. 1/2" pex. 3 zones. I noticed on another post some one placing pex on foam.I read closer to surface of concrete is better,actually was going to fasten to wire mesh. I almost sold on 4 post lift versus 2 post,versatility. Would I need to be concerned about placement on top concrete over pex? I'm using 4000psi concrete. Thanks.
I have radiant in my 32' by 32' workshop/garage, 4 loops as I believe the recommended max is 300 sq ft per loop. Cost to add loops is trivial, only manifold and valves will cost a bit more. I use a single pump (Gunfos 3 speed) for mine with manual variable flow valves. This setup give lots of flexibility to "tune" the heat in all areas, also provides the ability to add pumps after the fact if you feel they are needed. Larger loops will give you cold spots!!!
You should not place a lift on top of pex - pre-plan where/what you want, have 6-8" pads of concrete over a 3' circle at pressure points. Route pex around these pads.
Randy in Maine
Well-known member
Don't overthink this...you are heating up a rock using warm water. There will not be any "cold spots" in this 30'x60' rock.
I left out the 2" of insulation under where my lift posts will go and it gave me an additional 2" of 4000 psi concrete there.
I left out the 2" of insulation under where my lift posts will go and it gave me an additional 2" of 4000 psi concrete there.
Thanks,I'll get dimensions from lift co. Thinking 4 post Ben pak. Also looking at where best to buy pex 1/2" tubing. Since Zurn Sent Me Design Book thinking Zurn. Then I read Zurn has,had problems with bad brass fittings,ruining homes.lawsuit.What pex products and fittings are you guys using that work? Thanks.this will be my first project with radiant heat.
finn
Well-known member
Radiant floors won't have cold spots, but be aware that it will be expensive to operate if you aren't going to use the building full-time.
I added a secondary hanging heater so I could reduce the standby temperature and quickly raise the temperature on demand.
Works fine now, but I have two pieces of equipment to buy and maintain.
I added a secondary hanging heater so I could reduce the standby temperature and quickly raise the temperature on demand.
Works fine now, but I have two pieces of equipment to buy and maintain.
joel
Well-known member
Will a 4-post 9000# lift really be a problem if placed over PEX in a concrete slab? Reason I ask is it has been my experienced that I move the lift a few times before I find exactly where it will spend the vast majority of it's time.
finn
Well-known member
A 4 post lift probably has about the same contact pressure on the floor as a car sitting on the floor on its tires.
Shop Specialties
Well-known member
Radiant floors won't have cold spots, but be aware that it will be expensive to operate if you aren't going to use the building full-time.
I added a secondary hanging heater so I could reduce the standby temperature and quickly raise the temperature on demand.
Works fine now, but I have two pieces of equipment to buy and maintain.
How is it expensive to operate ? You only need a 1/3 of the BTU as compared to forced air to heat the same space. Once you get the slab up to temp it takes very little energy to maintain it. In the middle of Winter I have had customers go 2 days before they noticed the boiler was off and it was getting chilly in the shop.
You can end up with cold spots if you do not pipe the loops correctly. The trick is to provide a reverse return on the system. The RR balances the pressure drop in the loops. You can balance flow with valves, but the RR will make things easier.
finn
Well-known member
How is it expensive to operate ? You only need a 1/3 of the BTU as compared to forced air to heat the same space. Once you get the slab up to temp it takes very little energy to maintain it. In the middle of Winter I have had customers go 2 days before they noticed the boiler was off and it was getting chilly in the shop.
That's not how thermodynamics works. Heat loss is dictated by delta at between ambient and the room, and building thermal efficiency. There's no magic that makes radiant more efficient.
The main reason it costs more to heat with radiant is that it is impractical to keep the room at a low temperature and then dial the heat up when the room is occupied, i.e. thermally lag. That forces one to keep the temperature higher when unoccupied, or live with slow response.
Not a problem for a shop that is occupied 24/7, but an energy waster for a hobby shop, unless a secondary heater with faster response is added.
I have radiant in both my house and shop. Energy cost killed me a year ago, because of the randomness of my occupancy. Over the summer I added a hanging heater and keep the room temperature at about 42. The hanging heater is turned on when I'm working in there. I used perhaps 2/3 the fuel compared to keeping the temp in the fifties with radiant alone. The building is about 48'x75' with 16' ceilings .
Same with the house. Nice, even heat that works well if we're on a regular schedule, but not the best for intermittent occupancy.
There's lots of hype on radiant heat, but don't make your decision on testimonials.
Shop Specialties
Well-known member
It is not magic that makes radiant more efficient than forced air. Every boiler I have installed in the past 25 years has been sized roughly a 1/3 of the BTU as it would have taken with forced air. We did not install any forced air units with the radiant and every single one of the customers is 100% happy.
While the end result is the same for each type of heating they both doing it in a entirely different way.
While the end result is the same for each type of heating they both doing it in a entirely different way.
finn
Well-known member
???? A BTU is a BTU.
96% thermal efficiency is 96% thermal efficiency.
A boiler 1/3 the size of some other heat source will put 1/3 of the heat into a building in a given time period.
The building construction, leakage, and insulation determine heat loss.
A warm floor lets the occupants feel comfortable at a lower thermostat setting.
A slow responding system isn't efficient for variable heat requirements (non-continuous occupation)
96% thermal efficiency is 96% thermal efficiency.
A boiler 1/3 the size of some other heat source will put 1/3 of the heat into a building in a given time period.
The building construction, leakage, and insulation determine heat loss.
A warm floor lets the occupants feel comfortable at a lower thermostat setting.
A slow responding system isn't efficient for variable heat requirements (non-continuous occupation)
mygarageone
Well-known member
I constantly hear how radiant floor heat is expensive to operate , Bull !
Only from forced air contractors .
Only from forced air contractors .
donpauli2
Well-known member
Radiant heat is great. The only problem is when you have to drill in the floor for bolts or equipment hold downs you don't puncture a tube
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finn
Well-known member
I constantly hear how radiant floor heat is expensive to operate , Bull !
Only from forced air contractors .
I agree... for a building that is heated 24/7. BUT, for an intermittent occupancy hobby shop, one that isn't continuously occupied, radiant will be more expensive to operate because you are either continuously heating, even when unoccupied, or will be bringing a slab with lots of mass from a low temperature to a temperature above the set point.
For a shop that's used everyday, or even most days, radiant is great.
BadgerBoilerMN
Well-known member
Loop length, flow, water temperature and to a lesser degree tubing spacing determine the gradient of the slab. Cold spots are the result of bad design, much of it gleaned from "design by internet".
Radiant slab heating should save a minimum of 10% fuel but the source of fuel and the proper application determine the real savings. Over-sizing boilers, the lack of out door reset control and pp planning take their toll.
2" of 250 XPS is fine. The 1/2" tubing gets staple to the foam since lifting PEX anything less than 6" of concrete is a waste of time and brings the tube closer to your saw cuts. There are many barrier PEX tubing offerings made here in the US.
You can easily block out any mounting posts in the field of the slab as they do with heavy equipment in commercial applications. No insulation is necessary in these areas as long as they are within the frost-line--linearly from the outside wall. You may also get a CAD drawing so any future floor taps will be easy.
If you care more about saving money than being comfortable, radiant floor heating is not for you .
Radiant slab heating should save a minimum of 10% fuel but the source of fuel and the proper application determine the real savings. Over-sizing boilers, the lack of out door reset control and pp planning take their toll.
2" of 250 XPS is fine. The 1/2" tubing gets staple to the foam since lifting PEX anything less than 6" of concrete is a waste of time and brings the tube closer to your saw cuts. There are many barrier PEX tubing offerings made here in the US.
You can easily block out any mounting posts in the field of the slab as they do with heavy equipment in commercial applications. No insulation is necessary in these areas as long as they are within the frost-line--linearly from the outside wall. You may also get a CAD drawing so any future floor taps will be easy.
If you care more about saving money than being comfortable, radiant floor heating is not for you .
mygarageone
Well-known member
I agree... for a building that is heated 24/7. BUT, for an intermittent occupancy hobby shop, one that isn't continuously occupied, radiant will be more expensive to operate because you are either continuously heating, even when unoccupied, or will be bringing a slab with lots of mass from a low temperature to a temperature above the set point.
For a shop that's used everyday, or even most days, radiant is great.
But when all things are equal , radiant is cheaper hands down.
finn
Well-known member
Only if all things being equal means keeping the heat at working temperature, i.e. 50-60 degrees 24/7.
If all things being equal means working in the garage two random days per week, radiant is slow responding and offers no cost savings.
If all things being equal means working in the garage two random days per week, radiant is slow responding and offers no cost savings.
MagKarl
Well-known member
Keep up the good work finn. Spot on.
Shop Specialties
Well-known member
A properly designed and installed radiant system is not slow to respond. You are standing on the heat source being heated directly so it will take less heat =less BTU. People will say the forced air is faster because 9x out of 10 it is over sized past the determined BTU for the shop. Forced air is heating the air then you. So in order for that wind not to be cool you need bigger fire which requires more BTU.
A properly designed and installed radiant will be cheaper because it heats objects(humans included) directly with less BTU.
A properly designed and installed radiant will be cheaper because it heats objects(humans included) directly with less BTU.
BadgerBoilerMN
Well-known member
Shop is right.
A radiated slab will last longer, be more comfortable and operate for less than anything else. It is the only practical option for multi-fuel or a change of fuel in future.
Moreover, even at minimum temperatures of 50°F the space will feel warmer and if you need 10°F more on the weekend, you need only turn it up the night before.
If you are doing any physical work 50°F is probably all you can stand. Some of my farmers come in from the field and lay on the slab to warm up.
The only people that trash radiant floor heating are those that never had it. Tough cookies.
A radiated slab will last longer, be more comfortable and operate for less than anything else. It is the only practical option for multi-fuel or a change of fuel in future.
Moreover, even at minimum temperatures of 50°F the space will feel warmer and if you need 10°F more on the weekend, you need only turn it up the night before.
If you are doing any physical work 50°F is probably all you can stand. Some of my farmers come in from the field and lay on the slab to warm up.
The only people that trash radiant floor heating are those that never had it. Tough cookies.
Highbeam
Well-known member
A radiated slab will last longer, be more comfortable and operate for less than anything else. It is the only practical option for multi-fuel or a change of fuel in future.
I don't understand how you can say this. Heating water can be done with multi-fuels or a change of fuel in the future but so can forced air. For whatever reason, the heat pump folks making these awesome low temperature heat pumps are not focused on heating water but on heating air. Further, ducted systems for heating air also allow you to cool air for those folks that want cooling too.
BadgerBoilerMN
Well-known member
It is always cheaper to condition a building with scorched air, like a trailer house for instance.
Heating and cooling are not related but for the "advantage" afforded by the required duct work needed for effective cooling.
I believe we are still talking about a garage, where cooling is rarely required. Naturally I have both in my own shop and office but the garage section is radiated and ventilated.
When I last looked a Hot Dog may be field converted from NG to LP but don't try oil, waste oil, wood, pellets, corn or anything else that might burn in an outdoor boiler.
I own a couple of electric boilers at the moment. One is backed up with a condensing propane.
Nice to here you HB
Heating and cooling are not related but for the "advantage" afforded by the required duct work needed for effective cooling.
I believe we are still talking about a garage, where cooling is rarely required. Naturally I have both in my own shop and office but the garage section is radiated and ventilated.
When I last looked a Hot Dog may be field converted from NG to LP but don't try oil, waste oil, wood, pellets, corn or anything else that might burn in an outdoor boiler.
I own a couple of electric boilers at the moment. One is backed up with a condensing propane.
Nice to here you HB
mygarageone
Well-known member
No matter how you cut it , your floors will never be warm or comfortable with scorched air .
That dam furnace can run all day long and the floor will still be cold. Radiant heat floor slab or Infared are the only two ways to get the floor comfortable .
Talk to anyone who has had frost bite , they'll take radiant every time . I keep my garage at 55 in the winter and it's comfortable . Try that with scorched air , your going to be cold.
Badgerboiler is right , you can turn the heat up the night before .
That dam furnace can run all day long and the floor will still be cold. Radiant heat floor slab or Infared are the only two ways to get the floor comfortable .
Talk to anyone who has had frost bite , they'll take radiant every time . I keep my garage at 55 in the winter and it's comfortable . Try that with scorched air , your going to be cold.
Badgerboiler is right , you can turn the heat up the night before .
Randy in Maine
Well-known member
The radiant floor works for me in my garage because 1) I have stuff I don't want to freeze out there and 2) I don't want a flame out there to possibly ignite fuel vapors.
But really the cost to build/operate it and my comfort were the driving forces.
It really helps to have a really well insulated building that is also draft free. It cost more up front but then it is over.
But really the cost to build/operate it and my comfort were the driving forces.
It really helps to have a really well insulated building that is also draft free. It cost more up front but then it is over.
MagKarl
Well-known member
I would buy into the idea that maybe a radiant setup feels warmer at a lower temp, possibly allowing a lower temp set point.
joel
Well-known member
A 4 post lift probably has about the same contact pressure on the floor as a car sitting on the floor on its tires.
Good point! Thank you!
jask
Well-known member
...unless you add on the weight of the 4 post lift with a car sitting on top of it...Good point! Thank you!
then it would be about the same...
finn, Badger, and Shop, You are all spot on! I have a 40 X64 on radiant, if I plan to have winter work for 4-6 mos. I turn the temp to 56-58F, warm boots happy feet, long sleeve shirt. I'm a bit colder than Badger. NW Iowa(even though were South!)
86turbodsl
Well-known member
No better heat than radiant. Period. I have it in shop and house. My feet thank me daily. Try to keep your loops shorter than 300' if possible. At that length, the delta t between in and out gets high. Pumps cost more too. I have 8 250' loops in my shop, with 6" spacing on the outer perimeter and 12" spacing on the interior. I left insulation out under the lift points, and ran the tubing between the posts. The tubing is better on the bottom of the concrete, you don't get as hot a spot (striping) if the tubing is deeper.
And also, it's cheaper to run because you don't need to scorch the air to 70F only heat the slab to 50F or so. The delta T between indoor and outdoor is what drives the BTU requirements. It is better utilized in a higher usage building though i will agree with that part.
And also, it's cheaper to run because you don't need to scorch the air to 70F only heat the slab to 50F or so. The delta T between indoor and outdoor is what drives the BTU requirements. It is better utilized in a higher usage building though i will agree with that part.