In Floor heating

[Slick Fork]

Hi there,

I'm hoping someone out there can help me out... On our acreage, I have a detached shop/garage. The building is split in two with a workshop side and a garage side. Currently each side has a hanging forced air propane heater that are ridiculously expensive to run.

Now, the previous owners (we've been here 3 years) had installed the beginning of an in-floor heating system on the workshop side by laying the pex pipe down and pouring a concrete slab on top. So my question is, I'd like to finish the work on the in-floor system... from what I can see I'll need an expansion tank, manifold, heat source and circulation pump.

Now, drawing on my plumbing experience from the tank, I'm not worried about installing the manifold or the expansion/pressure tank. My question is on sizing the heat source and circulation pump.

So, given the portion to be heated is roughly 600 Sqft, with a very tall ceiling what can I use for a heat source? I was hoping for the sake of simplicity to put an electric hot water tank in.

What sort of flow and what can I use for a circulation pump?

And finally, Is this stuff I can get at Home Depot, Rona, Totem etc.?

Thanks

[lastlight]

Why not feed your tank water through it? Free chiller!

I'm SURE that won't work but it'd be pretty cool.

[sphelps]

I'd find a company that installs these kinds of systems and ask them, but I would assume if you have a general idea of what's needed to go bigger rather than smaller for the heating source. Heating systems work on a thermostat so if the heat source is a little big for the job it shouldn't really matter. The circulation pump will be a little more critical but if you can find out the recommended flow rate for the size piping you're using you should be able to simply multiply that by the number of pipes you're using.

[mike31154]

A little bit off on a tangent perhaps, but since you have an acreage, you might want to investigate a full blown geothermal system not only for the outbuildings but also for your home. They may be able to include the already installed pipe in the system. Fairly hefty investment and the pay back takes many years, but you're a little ahead of the game with an acreage. When I looked into it for my place I found out to install the geothermal loops, the contractors would have to drill deep vertical holes since my property is too small for horizontal loops. Horizontal tends to be less costly since it's less work to dig.

I'm in the process of renovating much of the flooring in my house and have installed a small run of electrical in floor heating under ceramic tile I laid at my living room bay window. Very small area and uses under 200 watts of power but does a decent job of keeping the tile cozy. The most expensive item was the damned programmable thermostat. I plan on doing the same when I tile the kitchen and bathroom. This will supplement the forced air gas furnace.

A number of years ago I rented a house in Germany that had hot water piping heating the tile floor in the bathroom. Many homes in central Europe use boilers to circulate hot water through radiators placed at the window in each room. This in floor system was tied into the main boiler that also supplied the radiators in the other rooms. That convinced me to make plans for in floor heating when I finally settled down in my own home. Reportedly more efficient than forced air systems by far since the warmth rises slowly. Forced air systems tend to send heat to the ceiling too quickly, so only tall folks benefit....

Best of luck with your project, should be a great way to go.

[MitchM]

I just built an 1800 sq ft. workshop with infloor heating. I use a NG boiler supplemented with 60 vacuum solar tubes. I really like the dustless infloor heat.

Use this heat loss calculator

http://www.builditsolar.com/Referenc...s/HeatLoss.htm

It will give you a good idea of what size heating unit you will be looking at.

What size/type pex pipe do you have?
Make sure that you get a compatible glycol.

Mitch

[MitchM]

A few other points:

my system runs at about 15 psi
the pumps are: http://www.bellgossett.com/productPa...rts-NRF-22.asp
the pumps run about 5 gpm, take 92 watts of power each
system temp is 120F

HTH,
Mitch

[MitchM]

One more thing...

If a pressure test has not been done on the pipes....do one.
If I remember correctly, we did 60 psi for 24 hours.

Mitch

[hillegom]

+1 on the pressure test.
You have to ask yourself, the previous owner went to the expense of laying the pipe, why did he install a different type of heating?

[russp]

I built a 1400 sq ft house with attached garage, for the main heat I installed a forced air furnace but I also ran in floor heat in the basement & garage. I used a standard 33 gal gas hot water heater & it works fantastic. It is a closed system and I run a max pressure of 10lbs hot. If you hire a plumber to install it they will tell you that it is not allowed but if you do it yourself it is a great way to go. I could easily maintain a 20dg temp all winter & the square footage of the heated area was about 1000 ft in the house & 500 in the garage. The main items you will need are a water heater , circ pump & expansion tank. but as previously mentioned the first step is to pressure test the pipe layout.

[intarsiabox]

A friend of mine just did in floor heating in his new garage. He was going to use a hot water tank but found that it is a code violation. He found a hell of a deal at Bartle & Gibson on a boiler, pump, manifold, plumbing, etc for only a couple hundred bucks more than a high effeciency hot water tank alone. The catch is he rebuilds classic cars and so did the salesman so he ended up with a better deal than most would, but even before this B&G was way cheaper than anywhere else.