Radiant Heating Anyone?

[DrDan]

That's it exactly Harv... Can't have any concrete touching copper. It will eat it up in a few years - I guess it's the lime in it. This PXC tubing is supposed to be good for 100 years. That's enough for me - I be in a place I don't need to worry about heat long before that.

DrDan

 

[Harv]

<font color=blue>PXC tubing is supposed to be good for 100 years</font color=blue>

That's a new one on me (PXC, that is). But then, a lot of things are new to me these days. /w3tcompact/icons/crazy.gif

I gather it's a type of polyethylene. Does it have good heat transfer properties? I guess it does or they wouldn't be using it for radiant heat.

Hmmmm... 100 years, eh? That's a good start, but I plan on living much longer than that. /w3tcompact/icons/wink.gif

 

[Egon]

But ifn you know how long it lasts you know when to trade in or maybe you will want to relocate after only 50 or so years.
Egon

 

[Mikemas]

Todd,
I may be able to give you some info on radiant heat. I designed and installed it in our home when we were building a few years back. It is good system, but there are some pros and cons.

Pros; very comfortable floors (nothing like stepping out of the shower on a cold day to a nice warm floor),
efficient (keeps the heat near the bottom of the room where it is needed, especially if you have a high cathedral ceiling), clean (minimizes air / dust movement), no ductwork (1" holes through floors and walls to run tubing)
Cons; price (twice the amount of a forced air system), labor intensive (insulate, insulate, insulate), no ductwork (a/c must be a stand alone unit), long recovery times (will not give an instant blast of heat like forced air, but it also holds the heat longer).

We are heating close to 3,000 square feet in our log home. The basement slab is insulated (bottom and sides). 4,000 psi mix with fiber and hepex tubing tied to reinforcing mesh. It is by far the most comfortable room in the house and the most comfortable basement I have been in. The upstairs is a standard plywood subfloor with the tubing run through aluminum plating in sleepers under the floor. The floors are covered with hardwood and ceramic tile. It radiates heat very well, but I feel the absolute best would be concrete with a ceramic tile covering. Two of the bedrooms are carpeted (thick), so we elected to use low profile wall radiators instead of radiant floor. The bedrooms are very comfortable also.
It is all heated by a natural gas boiler that provides domestic hot water from an immersed coil. I plan to add a high efficiency wood fired boiler with heat storage in the future. I would like to install this in my detached garage and run it to the house via insulated underground pipes. As you can see, radiant heating can accomodate heating needs for different rooms in various ways. Just figure out what your needs are and I think you will be very happy with it.

Good luck,

Mike

 

[MarkV]

Mike,
How have your hardwood floors done with the radiant heat system? I’ve been dealing with wood floors, as a contractor, for many years and flooring manufactures, in our part of the country, often discourage radiant heat. All wood floors will expand and contract with the seasonal changes in humidity. With a forced air system, this can be seen most dramatically around the floor registers. In the winter there will be gapping between individual floorboards and in the summer they become tight again. There is a school of thought that feels radiant heat draws to much moisture out of the wood flooring during heating season. If the flooring was not at the proper moisture content, at the time of installation, this can cause year round gapping in the floor.

Living in the south, our heating requirements are miniscule compared to many of you. As a result, we see very few radiant systems down here. I sure would like to hear anyone’s experiences with wood floors and radiant heat.

Happy Holiday’s Ya’ll,

MarkV

 

[Mikemas]

Mark,

Yes, the hardwood floors over radiant heat can be a very touchy subject. I have not had any problems to speak of in 6 years. I have witnessed a seasonal expansion and contraction on the floors and it doesn't seem to be any worse than floors without radiant heat. I used 3/8" Bruce prefinished planks in which the cross section looks like plywood. It was not recommended to use solid wood due to the potential for warping. The multiple ply structure with the grain running perpindicular in the planks was the only one recommended by Bruce for use over radiant floors. My floor has a rather generous expansion joint under the baseboard where it meets the walls. The whole floor is glued to underlaymant over a subfloor that is over the sleepers, aluminum plates, heat tubes and insulation. The whole floor sort of floats and expands and contracts as needed. Also, I acclimated the cartons of hardwood flooring in the house on the warm floor for about a month before installation.

Mike

 

[GlueGuy]

The floating floor concept sounds like a winner. Flooring contractors around here seem to advocate it. They just make sue the trim around the edges is big enough to cover the expansion/contraction.

The GlueGuy

 

[Paul_in_CT]

I`m about to put radiant floor heat in my first floor. I have a crawl space and will be putting the tubing in between the floor joists. I decieded to go with Kitec tubing from www.americanradiant.com . They are really good guys answered any question Ive had. As far as wood floors go that is pretty much and old problem. The earlier systems were designed to run at a hotter temperature (I think around 160-180 F) the newer systems run around 135 if I remember correctly. So even in a retrofit application (like mine) the wood floors should be fine. Two other friends of mine have put in radiant (one new construction and one retrofit) and both are very happy with the system. Now all I have to do is get my one manpower machine (my lazy a$$) started and get the tubing in /w3tcompact/icons/smile.gif .

 

[DrDan]

Sorry Harv

It is PEX tubing. It is thin walled so heat tranfer is pretty darn good.

DrDan

 

[Boondox]

PEX is wonderful stuff! I helped a friend install it in his floors (with little metal backings to direct the heat upwards) and it is the most comfortable, even heat I've ever experienced. Great to work with, very forgiving, and (from personal experience in my own basement last winter) it didn't rupture even when frozen solid!

Pete

www.GatewayToVermont.com

 

[DrDan]

Hey Pete

My god these holidays have to get over so I can get my mind together and order coffee - I am totally spoiled on that "La Minita Terrazu". Ooooh it is sooooooo good!

One of the very "big" benefits of in-floor radiant is it doesn't dry the hell out of the air. That's the thing I hate worst about winter - hands cracking and ya feel like an overroasted turkey all winter long. I may move out into my woodshop as soon as they get the dang concrete poured (If it "ever" quits raining).

DrDan

 

[Paul_in_CT]

Harv you are correct it is actually crosslinked polyethelene

 

[Rch]

http://www.jlconline.com/jlc/archive/energy/water_heater_heat/index.html
http://www.taunton.com/finehomebuilding/pages/h00028.asp
Here are 2 links re radiant heating, one with a hot water heater as the source (jlconline) and the other discusses PEX (about 80% into the taunton one)

RCH

 

[DrDan]

Those are some great links RCH! TU

I will have a picture up soon of my room where the tubing is down and concrete is yet to be poured.

I love that Polaris Hot Water heated. It is hi efficiency (vent gas is cool-run through PVC) and the insides are all stainless steel. Costs $1600 but well worth it.

DrDan

 

[MarkV]

Mike,

Thanks for the information! The laminated flooring, like your Bruce flooring, makes sense over radiant heat. The plywood type of layering would make the product much more stable. I have not installed glue down flooring for a good number of years now. We have done some in commercial applications over concrete, but I have kind of drifted away from that kind of work during the last 10 years.

I love radiant floor heating and it is good to hear it can be workable with wood floors. Thanks again for the information.

Happy Holidays

MarkV

 

[DrDan]

PEX PEX and More PEX

Here's the tubing ready for the pour - The manifold box forms conceal the hookup of the tubing. We have some scraps of concrete barrier insulation in front of the boxes to keep the pour away from the manifolds. As mentioned previously the lime in concrete eats copper and brass fittings so that's the reason for the forms.

 

[DrDan]

I\'d think twice about wood flooring

No matter what thickness - wood is an insulator and there will be heat loss.

Personally after staying in a bungelow in Goose, Holland for two weeks last year, I am sold on ceramic tile which is a much better conductor of heat. One of the drawbacks of ceramic is that it is cold, but not so with in floor heating. It can be cleaned so easily with a damp mop and drys in seconds with in floor heat. We loved it! Will be using it in our office room. I like wood too but hell put it on the walls and leave the floor something which is a better heat conductor - easier to maintain - more durable -etc.

DrDan