# Shop heating question



## BSzydlo (Jan 16, 2011)

I am considering building a separate shop building and initially am considering in floor radiant heat (concrete floor in MN). Another option would be electric, radiant ceiling panels and I am curious if anyone has any experience with this type of heating? Any advice would be greatly appreciated. In my current shop I have a ceiling mounted direct vent forced air heater which works ok (shop size approximately 400sq ft) but the new shop will be 800 sq ft and I am looking for an economical way to heat it.
Thanks in advance for any advice,
Bill


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## pintodeluxe (Sep 12, 2010)

I have heard that the stand-alone PTAC electric heat pumps do a good job. They are much more affordable than central heating. 
Efficiency may be an issue for you in MN though.


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## dbhost (Jul 20, 2009)

I guess it all depends on budget, and location. If you can afford to do it, radiant in floor heat takes forever to get going, but keeps everything comfortable once it is going.. Ceiling mounted heat makes no sense to me. Heat rises after all, not sinks…

As far as the heat source goes, that will depend on your location and budget again. Pellet, wood, gas, electric take your pick, whatever works for you. I have seen some folks that heat their homes up north with radiant heat that uses a self feeding pellet stove / furnace type gizmo for fuel. Burns reasonably clean, and cheap to boot. Not too cheap to set up sadly…

There are a couple of heater styles I personally would stay away from…

#1. Kerosene heaters. Heard horror stories about he moisture problems associated with Kerosene.
#2. The old style quartz floor standing space heaters. Those are a fire waiting to happen…
#3. Any sort of baseboard heating.
#4. Ceiling heat. Again, heat rises, so why mount your heat source above where you are?


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## teejk (Jan 19, 2011)

I went radiant in-floor in my new shop…30×40 heated, 16×30 cold…uses 60 gal LP hot water heater…R19 on the walls, R50 ceiling, 2" foam under the concrete. 5/8"s PEX tubing because it allows for a longer run per loop.

very comfortable at 60'F (that high mostly because of paint operations otherwise I'd drop to 50-55'F and still be comfy).

but not "cheap" LP wise (west central Wis). but comfort has its price and only heating 4 mos. I'll add foam insulation to the sides of the slab when weather permits (PITA) and see if it helps.

I'd be more than happy to share my "should have done" list (electrical/dust/etc.). .


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## ducky911 (Oct 6, 2010)

The flooring heat. Would take dust out of the equation and i think that is a plus.


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## teejk (Jan 19, 2011)

in-floor is "sweet" (I did it in the new house also…hanging tubes under the sub-floor) .

no forced air movement with radiant.

but you won't save much $$$ fuel wise in a properly insulated building…it's all about comfort (heat at your feet and legs makes you feel warm everywhere even though you might be freezing above the waist).


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## canadianchips (Mar 12, 2010)

I had in-floor heat in SASK. Canada. If there ever is a test ,that was the place. I swear by it ! Even in middle of Winter we opened large overhead door to bring machinery in, it did not take that long to recover.
My neighbors TRIED radiant heat in ceiling…..very disappointed, they all thought floor heat was better.


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## Manitario (Jul 4, 2010)

If I re-did my shop I'd put in-floor radient heat. I can't comment on the price to operate, but it is a steady, gentle, dustless heat source.


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## teejk (Jan 19, 2011)

agree Canadian…in-floor is nice but expensive to install (I think the tubing runs about 70 cents per foot and then you need all the manifolds etc.) and not much if anything to gain in operating costs. For me it's worth it…no drafts, cold/hot spots.

where in Sask btw? my dad became good friends with people in Humboldt and I used to go fishing in Dore Lake (1428 mile drive to get there!!!) but I'll never forget the experience nor will anybody that joined us. In fact my brother still wants to go back but I don't know if the lake is still making fish like it used to.


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## teejk (Jan 19, 2011)

manitario

you got it correct on all points. no operations savings really (but I have to insulate the slab edges yet and maybe that will change my mind). But it is comfy and no dust moving around unless I want it.

ignoring initial cost, biggest draw-back is you are "stuck" with your shop layout if you want any electric/ventilation in the slab. nick one of those PEX tubes and you will pay dearly.

I wish I would have run conduit and dust collection under the floor prior to pouring it but I hadn't decided yet on tool placement (coming from a small garage space I didn't realize how big 30'x40' space was). We lived 1000 miles away from the property and my wife and I only had a few days to lay the tubing before we had to go back.


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## jusfine (May 22, 2010)

In-slab heating is usually the best, most of the reasons already mentioned.

I have 12' high ceiling in my shop in the loft of my barn (Central Alberta), and use a 30' long radiant tube heater, works like a charm, keeps the tools warm, no air blowing around, (wooden) floor is warm to stand on, etc.

Highly recommend radiant tube heater if you decide not to go to in-slab.


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## Finn (May 26, 2010)

I am a retired heating contractor (Wisconsin) In floor heat is slow to react and expensive to install. Forced air gas its the way I would go. Even a space heater with a fan would work well. Unless you sleep in your shop it will be expensive to operate an in floor system. Turn it on when you walk in or with a timer and it has to heat up all that concrete before it starts to heat the air in the room.


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## UltimateCarvercom (Feb 20, 2012)

I would agree with in floor heat as well. If you do any finishing you don't want air turbulaunce and the heat is even. Yes it is slow to react so you leave it on at one temp. I would also insulate the slab as you do loose heat in the concrete so important to insuluate under and at the edges.

Heat pumps have made some progress with tempertures but still is not efficent at under 20 degrees temps. Of course force air would be the cheapest if you have natural gas but you are moving air and that can affect projects if you do the finishing. My money is on infloor heat with hot water heater. Comfort for a couple hundred dollars a year more. No issues.


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## teejk (Jan 19, 2011)

jim finn

In-floor is VERY expensive to install…we did it (my wife and I)...

Radiant in my shop running at 50'F feels comfy. I don't think I could say the same with a few "hot-dogs" hung in corners away from finishing areas…there is some spooky feeling about warm feet and legs that radiant provides…dunno why…

but all in all, if I lived a few hundred miles south of here, I'd figure out something with forced air (based solely on the initial install costs).


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## teejk (Jan 19, 2011)

ultimate…

since we (my wife and I) already did it (without the benefit of a PEX unroller btw since my heating guy tried a cheap one once and hated it), I'll say I love it. In our climate a few days to ramp up or down are nothing. We did put down 2" foam below the slab…in the spring I'll dig out the perimeter and add rigid foam there as well. Not looking forward to it.

p.s. a great biz opportunity for anybody that could invent a system to "inject" foam around slabs.


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## RogerM (Oct 31, 2011)

I live in the south and built a separate shop with a concrete floor. I considered hot water floor circulating but no contractor down here was available or willing to put in such a system. I ended up with a heat pump and a wood heat stove and absolutely love both. I have 2 X 6 walls and a 16" I joist ceiling consequently I was able to put in a lot of insulation(R 32 in the walls and R 60 in the ceiling). Based on my experience the first and best thing to focus on is the insulation. Firewood is abundant down here and I love the wood stove in the winter. It is also real good in getting rid of a lot of scraps.


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## BSzydlo (Jan 16, 2011)

First of all I would like to thank everyone for all your input. It looks like in floor heat is the way to go. For those of you who have used it can you recommend a heating source. Water heater or dedicated boiler? What about fuel source, LP or electric? All the heating for my home and shop is currently on LP but the price of LP is rising here in MN. Anybody have a crystal ball as to which will be more economical in the future?
Thanks again,
Bill


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## revanson11 (Jan 5, 2012)

In my last two shops I have used and Empire 35,000 BTU direct vent LP heater. My shop is 560 sq. ft. with a ten foot ceiling and has 1 1/2" rigid styrofoam (pink board) on top of slab covered by 3/4" tongue and groove Sturdy Floor. The walls are R19 and the ceiling is R50. When I walk in the shop I flip the thermostat to 60 and also turn on the air filter to move the heat around. Works very well. When I leave I just turn the thermostat down to 45. The direct vent heater is totally sealed from indoor air and dust. If the outside temp is 30 degrees or higher just the heat from the pilot light seems to keep the temp up some by itself. I have never experienced cold feet in the shop even though I live in central MN.


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## Racer2007 (Jan 13, 2011)

I think some kiind of forced air heating is best (gas elect whatever)since it warms up the area faster than in floor heating, but also add as much insulation as you can,you can put in extra fans to move the heat around faster. and you could add some infloor heating to keep the floor warm, but then who sits on the floor.


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## Grandpa (Jan 28, 2011)

I probably can't help much since I live in SW Oklahoma. I have a 1200 ft shop with 10 walls. It is steel so there is only the thin insulation that stretches over the frame before the sheet metal is attached. Concrete floor with no insulation around it or under it. I heat it with a Kerosene heater and have had no moisture problems. I can bring mine up from the off position to shirt sleeve working in 20 minutes. I keep a couple of doors slightly open to keep a fresh air source and I love it. I have the forced air jet shaped noisy heater so it is good that it doesn't stay on long. I will say in our area they make electricity by burning natural gas so it is always cheaper to use gas than to buy electricity. they tell us that the single greatest user of a homes electricity is the water heater.


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## mrtoasty (Jan 13, 2011)

In floor is the only way to go. My shop is a 1036 square feet with 10'6" walls and it does a great job. I leave it set on 55 to 60 and it is just right. Insulation is the trick, 2" foam under the floor and around the perimeter, keep the pex at least 1' from the edge of the slab so you are not trying to heat the outside.

I live in Indiana and I heat the whole thing with a small continuous hot water heater. It is a small unit like goes under a sink. It has two heat elements at 4500 watts each, but you only need one of them. I got it at Menards (Indiana big box store) for 165 dollars.

Les


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## canadianchips (Mar 12, 2010)

You have me still Thinking about this !
Check out the different "FIRE INSURANCE " rates on the different types of heating as well.


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## bigfoot62 (Feb 3, 2012)

My Son put in floor pex's tubing in floor, to heat his brand new garage this year and his first electric bill was 600. Dollars. He lives in the northern part of Ohio. So I would agree that natural gas forced air is the best way to go!


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## canadianchips (Mar 12, 2010)

bigfoot62.
Not sure why your sons electric bill was that high. The in floor heating I talk about uses HOT WATER and a boiler .Lots of boiler options these days. Electric hot water heater for this is not one of them !


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## jerkylips (May 13, 2011)

There are a lot of benefits to radiant floor heat, & if we were to build another house I'd definitely look at it. In a shop, I see a drawback, though. If I'm off-base on this one, please let me know. The "slow to respond" comments have already been made. If you don't have the system on, it's going to take a fair amount of time to heat the slab & actually get the shop warm. Unless you plan to turn the heat on hours before you go out to the shop, you would be heating it all the time, whether you're out there or not. If it were me, I'd rather turn on the heat when I'm in the shop rather than heating all the time..


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## Charlie5791 (Feb 21, 2012)

The best way to use in-slab radiant heat is to marry it to solar hot water heat. A friend of mine built his (aproximately) 2500 sq ft single floor house with in-slab radiant heating. He has about a 300 gallon tank that just tempers the water. Something about adding volume so it cools less quickly. That tank is heavily insulated. The liquid in the solar panels is an antifreeze of some type, and it has a coil in the tempering tank to do heat exchange.

He has the insulation under the slab and his perimeter insulation angles down at almost 45 degrees as it gets farther from the slab. Perimeter insulation extends out about 3 ft from the slab. It's VERY slow to respond, but it FEELS much more comfortable at lower temperatures than a house with "heated air" type heating. He found it best to simply leave it at a certain temperature and forget about turning it down and turning it up. He said he wasn't saving anything by turning it down because it took so much (thermal) energy to bring it back up. So now he leaves it alone unless he's going to be gone more than a week. Now that he "got the hang of it" his heating costs are next to nothing. His next addition will be an outdoor wood furnace, piped into the tempering tank.

Oh, and his walls are on 12 inch masonry "risers" so if the whole thing took a dump on him, he could pour another floor over the exising and encase pex in that as well. He doesn't anticipate the pex wearing out in his lifetime though at this point.


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## jerkylips (May 13, 2011)

Charlie -

I was interested in something similar to what you're describing, but always had a question - is there a way to "turn off" the solar collectors in the summer, when you don't want to heat your home? From what I understand, these would normally be tied also to your water heater, but in the summer, the supply of heat far outweighs the demand for hot water. It seems like you could overheat the system.

I know people have done this, so it does work - just not sure HOW. I heard another person (on another site) that had a very similar setup, but instead of solar, it was a wood gasification boiler, & something like a 7500 gallon tank. Apparently he was heating the house on about a cord of wood per YEAR.


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## Charlie5791 (Feb 21, 2012)

In my own shop which is only about 300sq ft, I have a small salamander heater. Runs off a 20# lp tank like a gas grill. I run it on low (30,000 BTU) for about an hour and my shop is nice and toasty, but the salamander is noisy. So I shut it off and turn on a quartz heater. That works for a good long time before I feel like turning on the gas heater again.

Probably not real efficient to do it this way but…. small shop, totally insulated, seems ok for this year. What I'm hoping to do is install a couple of radiant cove heaters. (like these)

Total about $400 for the heaters and a thermostat. I worked in a garage that had these. A friend keeps his pet '68 Camaro in it. It was like working in the sunshine and it warmed OBJECTS like the car and the floor and the workbench and the TOOLS!  They took no floor space (which is at a premium in my small shop) and weren't crazy expensive to operate. In fact he took OUT a gas heater and replaced it with these and he's spending significantly less because you don't need to have the temperature set as warm to FEEL warm in the garage.

They run at a safe, low temperature and he got them partly because they're safer than anything with a flame. They also don't add moisture to the air. I can't afford in-slab heat. The install cost was just too high. It's really nice, but if I insisted on in-slab heat, I still wouldn't have my workshop. The radiant cove heaters are affordable for me. Plus they react fast. Turn 'em up and you're comfy in 15 minutes. I can turn them down to 40 or 45 when it's brually cold out. I calculated it out (with help from a HVAC guy) that if we have a SEVERE cold snap that lasts a month …. because we've had them… with temps in the single digits to mid-teens and never getting higher…. for a month… that it would cost me about $60 for that month to keep the shop at 50 (average). And with those cove heaters you can work in a t-shirt comfortably at set temps of about 60.

Electric hot air heat? Never. Way too wasteful. But the electric radiant panels are worth a look.


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## Charlie5791 (Feb 21, 2012)

Jerkylips,

yeah, you turn off the solar by draining it into a holding tank. This guy lets the tempering tank get as hot as the solar can make it and has the inlet water for his domestic hot water coiling through that tempering tank as well. it brings up the temp of the water entering his hot water tank so it doesn't have to work so hard to recover from hot water useage. He's never overheated anything. His solar assist is from a 4ft x 24ft mat-full-of-tubing originally made to heat a swimming pool. It's in a stationary framed mount on top of his garage


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## BSzydlo (Jan 16, 2011)

As my research continues into in floor heating has anyone used this website http://www.radiantmadesimple.com
From previous posts it seems that the slab takes a while to cool down or heat up. If using electric as a fuel source this seems like an ideal situation to take advantage of off peak discounts. If the heat was only on between 8pm and 6am would that work with this type of system?
Thanks again for all the info.


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## KenFitz (May 21, 2007)

When I decided to heat my shop (an old barn built in 1860) I knew I wouldn't heat 24 hours a day, so I wanted something that would heat up the shop quick should I decide on the spur of the moment to work there. After much research in to all types of heating including in floor, I decided that a gas forced air would meet my needs here in Massachusetts. My shop as currently configured is a little over 500 sq ft. I bought a unit that would handle double that in case of design changes over the years.

I purchased a Hot Dawg 75,000 btu propane model (they do make natural gas) that hangs from the ceiling in the back of the shop. I have been extremely satisfied with its performance and speed of heating the shop. I can go out in the morning and flip the switch and then take the dog for a 30 minute walk. When we return it's 70 degrees inside when its below zero outside. I keep covers on all my equiptment to keep condensation/then rust off and they work perfectly. Not even a hint of rust. Four years in operation now and it has never failed me once. If you have access to propane delivery (I got a 100lb tank) and a well insulated shop a fill up each winter will keep you nice and cozy when you are working.

When I installed my new pine t and g floor this year, I left the heat on for a month and it did eat through the tank using about 3/4 of the tank in a month. That's not the norm. I usually work out there 4-5 days a week and as I said one tank full per winter has kept the old bones from rattling.

The system cost me $475 on the internet plus around $50 in shipping costs. It's an easy install and the system works off a regular house thermostat. Hope this information helps.

Ken


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## BSzydlo (Jan 16, 2011)

Ken, do you keep the thermostat set at a certain temp when you are not in the shop or do you turn it off completely. I currently use a similar ceiling mounted device but I keep the temp set at 50 in order to prevent the temperature dropping too much if I don't get out to the shop for a few days.


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## canadianchips (Mar 12, 2010)

My shop back in sask, I kept the heat on low all the time. It was cheaper than letting slab freeze and trying to heat it up just to work few days a week.
If solar type collectors are used with antifreeze in them you would *not* tie it into the hot water system for the rest of the house. Even a geothermal system,( drawing warm water from the ground) used antifreeze, it is a CLOSED loop. The resevoir will be large enough for expansion of any extra hot water coming back. Most floor systems have "ZONES" with individual temperature switches that would allow you to control temperature in different zones. The only time new HOT water is introduced into the LOOP is when the loop has cooled below thermostat setting.HOT water is introduced and cooler water goes back into resevoit to be re-heated. 
EXAMPLE of ZONES: House heated with floor heat in basement, bathrooms and upper levels would each have there own zone with thermostat switch, some people heat floor in car garage, another zone, . 1 boiler is used. The pipes can also be run underground to workshop. The more you heat with water, the more economical it will become.


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## KenFitz (May 21, 2007)

Bill,

I turn the heat off completely when not in there. It gets cold but with all the extra insulation I put around the perimeter
above and below I don't think it ever went below 15 . Keep in mind I'm pretty regular out there so at most it might be three days without heat. Although we have gone on a couple of cruises in Jan and Feb so I guess it has gone as long as two weeks. I haven't seen any downside to this in four years actually five years now. Propane here just hit 4.00 per gal. I wish I had the natural gas model. I would run a pipe from the house. It would be even cheaper.


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## BSzydlo (Jan 16, 2011)

Ken, I am basically down to 2 choices. Either a ceiling mount forced air (LP) or an in floor electric. Currently I keep the heat on in my shop (around 50) because I have always been concerned of what effect it would have on the tools if it got too cold. I don't know if it is necessary but paying extra for maintenance heat seems better than repairing tools. While talking to an in floor radiant contractor he basically said that to heat the floor would be approximately 7 khw/hour and then 50% of that to maintain. The advantages being I could use off peak electric. The disadvantage being that it would be less flexible than forced air and much more costly to install. I currently have LP for my home and shop and I am amazed at how expensive LP is getting. I am trying to figure out a cost comparison between the two systems but there are so many variables that I don't know if it is possible. Since I am retiring this year I one of my major concerns is what the annual cost will be.


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## KenFitz (May 21, 2007)

Bill

Retired myself three years ago so know that cost is definitely a consideration. I worried about what the cold would do to the tools and they seem to be just fine. I cover anything metal with tool tarps bought at woodcraft which supposedly keeps condensation off. Like I said before no rust at all. Anyway good luck. You have to do what is good for you. I'll be watching to see how,it turns out.

Ken


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## mrtoasty (Jan 13, 2011)

Bill,

It looks like you are getting a lot of advice. I don't know how big your shop is going to be, but 1/2" pex tubing is 26 cents a foot at my local big box store. If nothing else you can put in the tubing and the required insulation under the floor just in case you want to go with floor later. I used 1000' in my 1000 sf shop.

Something you might want to look at, with propane at 4.00 a gallon and propane heaters at say 75% Efficiently , you are getting about 69,000 btu for your 4.00. If electricity is .10 per KWH the same 69,000 btu is just a touch over 2.00. In floor heat is 100% Efficient or very close.

Just food for thought.

Les


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## teejk (Jan 19, 2011)

les

tubing for radiant heat is different than plumbing (O2 barrier). But I just checked and see that prices have dropped A LOT since I built (think I paid 50 cents per foot 2 years ago), now appears to be running at about 35 cents if you get the 1,000' roll. IMHO it is worth every dime…warm feet/legs so even at 50F I am comfy, no noise other than when the power vent on the LP water heater kicks in (rare once the slab heats up) and no junk floating around in the air (from the heat source that is…always junk floating around but comes from tools).

keeping the heat at 50F (other than when I have paint operations going…I might be comfy at 50F, paint is paint and wants a little more)...try to work on a cast iron table saw cooled to 15F!


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## MrRon (Jul 9, 2009)

In floor radiant heat is great, but expensive to run. It needs to be running all the time, especially in Mn. It takes time for heat to reach your setting. If you shut it down, it could freeze. Regardless of the heating system used, insulation is the most important thing.


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## Hemlockhollow (Jan 14, 2011)

My shop is around 450 square feet, I have a ceiling mounted modine style heater that is hot water that circulates the residual hot water from my house and a wood stove. I leave the thermostat at 50 degrees and use the wood stove during the day. My only cost is the electricity for the circulation pump.


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## roman (Sep 28, 2007)

done them all

cant beat in floor radiant heat.

heat bill went from (with radiant tube heaters on ceiling) 800 a month to heat a super insulated shop to 300 for the entire season, when the "in floor" radiant heat/boiler was turned on, which included running the spray booth which had previously sucked the heat out in seconds

been in the construction industry for over 30 years…………..you cannot beat (if you have the money for the initial investment) the return value on your buck………for radiant heat……..no way, no how

I would do more home work, on the boiler, that fires up the system, if I ever did it again, as you cut the cost in half again, ……by spending even more

gas is 4 bucks a gallon……………and it will continue to rise


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## BobM001 (Jan 8, 2012)

If you have natural gas available then in floor radiant with a Navien 91+AFUE These have a 10:1 turn down ratio for burner modulation with outdoor reset and slab sensor. I assume you will have a concrete floor. If so your system would be a slab on grade system Instead of the 2" polystyrene foam board there is the thin film Barrier Insulation Depending on where you live you will have to put glycol in the system. This means NO MAKE UP WATER FEED to the system. Plus a 30% solution stength would be plenty to prevent burst.

Now, no gas, then by all means, Liesure Line Coal With their "Coal-A-Trol" ethernet cable connected temperature controller the capacity modulates the stoker from 5000 BTU- 70000 BTU. It also modulates the blower. The hopper holds 110 lbs of rice coal. 40 lb bags run about $8.50. By the ton it's cheaper. The only other cheaper would be wood. But it's a lot of work and it's messy. I installed the Pocono Back vent into my friend's house. This was after he spent $3500 one winter on heating oil and kept the house at 65. In ONE YEAR the cost in fuel savings paid for the stove and he kept the house at 70. I did a combustion analysis on this. At "high fire" with a Testo 330 analyzer I got 82% efficiency.


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## BSzydlo (Jan 16, 2011)

First of all I would like to thank everyone for all the suggestions and recommendations. For those of you with in floor heat do floor coverings such as anti fatigue mats have an impact on the heating qualities of the slab? I have electric radiant heat under floor tiles in my bathroom and have noticed a difference if a bath mat is placed on the floor. It is very warm under the mat but not so on top.
Bill


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## teejk (Jan 19, 2011)

The guy sells design services…considered "the expert" by some people, less glowing reviews by others. But his site offers a ton of info on radiant heating systems (insulation, heat source etc.).

http://www.radiantdesigninstitute.com/index.html


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