Shop radiant floor heat

[Hoeman00]

When I built my house addition (new basement under
1/2 of the 150yr old part too) I put 2" dow under floor and
used the orange PEP tubing tied to concrete mesh
before pouring the floor.
Did this in the attached garage 26' X 28' X 12' hi also.
I have an outside wood fired boiler w/ 3 zones,
1 for forced air heat in the 60 x 40 x 15' shop.
1 for forced air heat in house 4000+ sq. ft.
1 for the floor radiant heat.
To do floor radiant u need 1' of tubing/ 1 sq. ft. of floor.
The floor has 4 300' loops and garage has 2 300' loops
all hooked to same manifold (this lets me adjust temp
between the house and garage).
The warm floor is GREAT, feet feel good when standing
or laying on it when working.
Use one of the digital thermastats that u can set
different times and temps (when working in morning
set it to start heating at 4 am. or so).
This is VERY efficient heat and w/ my basement
set at 72*(garage is 75*) u sweat when working.
I would recommend 60* range for general working
in t shirt.

 

[AndyR]

Did you add air transfer coils to your existing furnaces when you went to the outside boiler? I am thinking of much the same setup - but hopefully with a few solar hot water panels so I don't have to fire the boiler on cool days.

 

[MossRoad]

We had a heated floor where I use to work. It used about 600 gallons of kerosene every month! But it was an airplane hangar /w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif BIG building.

That floor was so nice to work on. You could pull in a wet sloppy snowy vehicle at night and by morning everything was melted off and evaporated off the floor. You would have to lay on cardboard to keep from sweating. If you had a puddle on the floor, you could squeegee it out and it would dry in 5 minutes. And if you had to open the doors and let all the heat out, as soon as you closed the doors it would get warm again. Just about instantly.

The downside was, it took a day to get it going from a stop. No instant heat there. We had some type of ethylene glycol mixture in it so it wouldn't freeze.

I plan on heating our next house this way. There are so many ways to generate hot water that I won't be tied to one fuel source either.

Good luck.

 

[DougM]

Could some one Post pictures of how every thing is
Plumbed ??/

would help me a lot

Doug

 

[boustany]

Make sure, make real, real sure, that 6 mil or so plastic is laid over the foam insulation before the concrete is poured. Otherwise, you'll see cracking like you've never seen before, on acount of the concrete stick to the foam like you wouldn't believe, so as it contracts, it cracks. And make sure they use reinforcong mesh (i.e. 6" grid) which keeps the cracks down too, and gives you something to attach the PEX to.
My house/basement is radient. Works swell, but I'm not sure I'd use in it a shop unless I was planning on living in it. It can take a day or more to heat a slab to temperature, so you'll have to maintain heat even when you are not using it.
I designed/installed my complete system. Happy to help anybody who is interested.

 

[Hoeman00]

Yes I added a coil to the shop and in process
of adding one to the house now that we have
the new ductwork run.
Only problem is the heat exchanger in the
furnace is cracked so for heat, until I can
find an exchanger, the hot water coil is
setting in the old kitchen and a fan blowing
across it
Boy the old kitchen is HOT

 

[JEP]

I can give you a cost reference. My neighbor has a 60' X 120' barn with 14' ceilings. Half of it is insulated and heated so 3600 sq. ft. He keeps the floor temperature at 70 F and it cost him $600 the first year. Not bad I thought. He has a oil boiler at ~$1.30 per gallon or about 460 gallons. The insulation is similar to what you are using, maybe a little better. This is in Southern Michigan where is gets below 0 F at least a few times a year.

Someone else can check my conversion or technique:
The BTU value of on gallon #2 Fuel oil 137199 BTU
BTU to kWh one gallon oil is 40.2 kWh
Multiple by 80% efficient hot water heater 32.1 kWh
Multiply by 460 gallons is 14788 kWh per year
Multiply by $.05 per kWh (don't know what you mean by cheap electricity, you can multiply by your local cost) $740 a year electric.

Again this is for a building that is almost 4 times the size of yours and a little colder climate.

JEP

 

[zenmek]

Thanks for that post, it was very informative. As far as your formula, it sounds good to me! Our electric (All electric residential rate) is currently $0.043 per Kwh, so That would translate to a very affordable option.

 

[Rch]

<A target="_blank" HREF=http://www.jlconline.com/cgi-bin/jlconline.storefront/3de933580076b6e0271a401e1d290643/Product/View/9811usin>http://www.jlconline.com/cgi-bin/jlconline.storefront/3de933580076b6e0271a401e1d290643/Product/View/9811usin</A>
Good reference for hot water tank radiant heat. Note the author !

 

[zenmek]

Ole Bill just never stops amazing me! I bet Hillary actually wrote it though /w3tcompact/icons/laugh.gif