Radiant floor last minute thoughts

[Mr.atc]

Hey guys, what a great source of information here.

For the last several weeks, I've been on here reading everything I can about radiant floor heat. (many nights until the wee hours of the morning until I can't stay awake.) I have been planning my building for a couple of years and really, really wanted heat in the floor. Now I've come to the point of pulling the trigger or the plug on it. I just can't seem to justify the expense and projected operating cost unless I do solar. I don't have NG so propane would be my other fuel choice. I have priced a central unit and could put that in for thousands less(DIY) and I would have A/C too!!!!

The picture of the rear was this week around 1:00pm. The rear faces south and there are trees all behind it. It will never get any unobstructed sunlight. With the leaves off, does this look like enough sunlight to power the floor?

I am ready to get the concrete guy over to put in the gravel and compact it so now is the time to make the decision. I have set my garage door height for 2" of foam under the slab as the framing was done prior to me getting down to the nitty gritty on in floor heat cost. I would be doing the install all myself as I have built the entire building myself over the last 5 months. (I had to as my budget isn't big enough to pay anyone else)

The building is 60x60 with 16'walls on the center section and 10'6" on the outer walls. It will be all open inside. Currently it has double bubble around everything but I will be putting more insulation up later as soon as I can decide on what kind I want to use. Right now I will be using it only on nights and weekends but in a few years I could be out there more.

I have not found any deals on craigslist (or anywhere else) for any XPS and the one quote I got online was $10,000 for it. I can get 25psi EPS locally for about $2900. From what I've read, it would be almost as good.

I have read about how complicated/high maintenance the radiant systems are and I just think I want something simple. I am thinking of radiant tube heaters also as my second choice but obviously I couldn't do solar with that.

I do paint and bodywork and hate laying on a cold floor.

Just trying to see if it's one of those pay me now or pay me later kind of things? Thanks in advance for all the input.



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[Firebrick43]

Never met any one yet that regrets radiant heated floors but tons that regret not doing it. Size of our building is going to make a more complex system. You will not have enough sun light to power the floor 100 percent even if you chopped down the trees and put full panels on the back. And just saying, if your having a hard time swallowing the cost of xps the solar system that big will make your head spin.

Please don't take this the wrong way but it sounds like your trying to justify things to yourself. Even if it's not a hobby and your a one man part time body man it really hard if not impossible to justify a building that big. You do it because you want it and throw the justifications out the window.

Just a thought. Do you really need to heat all of it. Partion off the wings for storage and where the paint booth will be. The storage areas need little or no heat. The booth only needs heat while painting and done with heat panels. Just put I slab heat where you are going to do actual work, bench areas, paint mixing/storage and a man cave area?

have some tube or forced air heat as well but the warm slabs and tools that are on it won't be comfortable even if the surrounding air needs raised quickly by other means

 

[Mr.atc]

Firebrick43

Well, I haven't priced the parts for the solar but that would be a homemade system, I didn't think it would be THAT much. I could be wrong and have been before.

 

[PWC Repair]

I was in the same boat as you with decisions about heat. EPS is just fine. Check craigslist for chicken house. They tear them down and repurpose the materials, including EPS sheets. I read enough about the floor heat to just do it. You can't go back and do it later. It was an expense I could have done without as I'm going on 4 years now trying to build mine. Then again I'd rather not regret it.

 

[Firebrick43]

I have been over on builditsolar for years and have built a small solar air heater for my small shed. I am not trying to discourage you from building one just stating its expensive and paybacks can be long. Most big HW spacing articals written there have no cost stated

Gary reysa articles do. Take this one for example.

http://www.motherearthnews.com/diy/solar-heating-plan-zmaz07djzgoe

http://www.motherearthnews.com/diy/solar-heating-plan-zmaz07djzgoe
I know your system won't have some of the same things but it's also been several years since being written and material cost have risen.

So if you read the article and the cost you will notice two things. One is you will need a system twice the size (maybe not quite twice the cost however). Even then it won't cover 100 percent of the heating. Second is for his 4200 dollar investment he is saving 740 a year on 340 gallons of propane. In Montana that may be the going rate??? Here in the Midwest if you own your own tank and have them summer fill its around or even less than a dollar a gallon. His 5 1/2 year payback will be 11 years for me. It's a tough call?

One big problem is most HW systems are for domestic use hot water and that works ok because people only use hot water typically to do dishes or showers in the evening after a day of sun. Also most of the time the preheat incoming well water (55 degrees) to the hot water heater which drastically reduce amount the hwh works.

Building Heating loads are constant if not higher when the sun is not shining, which means thermal storage and more complex controlling, valves, and pumps. This adds significantly to the cost of construction and of the maintenance.