Under floor heating

[Boffin]

A while back someone posted details of an underfloor heating system that was self-regulating and could be retrofitted in the sub-floor area. I can't find the original post and I was wondering if any one had the details.

 

Andy

[Gregori]

Might have been Jamie? (KMG_365)

I know he put electric radiant heating in during his remodel.

[Boffin]

I think it did get mentioned during his install.

Luckily I was able to track it down via Google. The systemI was looking for is http://www.stepwarmfloor.co.uk/index.htm

 

Cya, Andy

[ESokoloff]

That looks like the same manufacture of the system Jamie installed.

 

I have to wonder tho if this would sufficiently heat a house outside of sunny SoCal

[Quinn]

It sure seems like a nice idea for a bathroom under the tile floor. I question how good it would be installed on the underside of a subfloor with wood flooring on top of that. It would have to get the heat up through almost two inches of solid wood and partical board while not losing most of it through R-17 insulation between the floor joices. I also wonder what the constant heat drying out the wood flooring would do to it.

[Berkley]

My dad retrofitted it in the flooring in parts of his house in the Northeast. He specifically used it in the entryway (soapstone floor) and the new bathroom they put in (also soapstone floor).

 

The soapstone is great - radiant heat all the way!

 

http://www.rodzander.com

[f86sabre]

 

I have to wonder tho if this would sufficiently heat a house outside of sunny SoCal

 

They use that tech in some of the colder areas of Europe and it works fine. I know of some homes in Minnesota that use something like it also and they have good luck with it.

[Boffin]

This is going down under a ceramic tiled floor in the kitchen. British houses are mostly brick or stone built with no sub-floor space. In this case there is a concrete foundation slab, then a layer of insulation followed by the heater then finally the tiles.

 

Andy

[ESokoloff]

 

I have to wonder tho if this would sufficiently heat a house outside of sunny SoCal

 

They use that tech in some of the colder areas of Europe and it works fine. I know of some homes in Minnesota that use something like it also and they have good luck with it.

 

I'm not questioning the tech(nique), but rather this particular system.

5 amps @ 24v is only 120-watts.

It may be enough to sufficiently warm the floor but will it be enough to adequately heat the entire house?

[Tony_K]

It may be enough to sufficiently warm the floor but will it be enough to adequately heat the entire house?

 

Radiant floor heat is only for a comfort factor. It's not intended to heat the home only a cold floor usually in a bathroom.

[Woodie]

It may be enough to sufficiently warm the floor but will it be enough to adequately heat the entire house?

 

Radiant floor heat is only for a comfort factor. It's not intended to heat the home only a cold floor usually in a bathroom.

Not true. I'm planning on heating an addition solely with radiant heat. (central Connecticut, 4 seasons including wayyyyy too much of that white stuff that falls from the sky.)

 

Hot water, above the subfloor, under oak flooring: water temp required is 127F.

Hot water, below the subfloor, same flooring: water temp required: 145F.

 

I'm opting for the above-the-floor install.

[USAF1]

My parents built their own home back about 1948-49 or so.....with in-floor heating............thru the whole house!! Concrete foundation of course. But, many a time I remember walking into the kitchen or the bathroom (tiled), and not being able to stand in one spot too long......it was that hot! Sure wish I had it in my house today!

 

Pat

[Flyer5]

I have hot water radiant heat under my floors . Love it, used 5 ton of coal to heat my home this winter including the domestic hot water . We are in a cold area of the N.E. on top of a hill . Works great . The best thing about it is when your feet are freezing from being outside when you come inside and take your shoes off you feel 90 degree floors . Warms you right up .There are lots of different systems out there . Dave

[KMG_365]

Yes Andy that was the stuff. We love it!

 

I don't know if you have the room for a concrete backerboard between the concrete floor and the ceramic tile, but the ceramic tile is generally too thin to spread the heat out and you'll need less space in between (i.e. more heating material) to avoid cold spots. Also, a thin and small dimensional ceramic tile will bond better to a more uniform surface like backer board.

 

When it gets down to freezing here we do have to turn it up all the way and finally close the windows, but otherwise it works almost too well!

[Rob_Mayes]

I can see where it would be great undet tiled floor in the bathroom.

 

I check into hot water tube/heat in the concrete floor of a garage I am building. If I always wanted to keep the garage warm, it would be the way to go, despite the high cost. If I plan on just wanting to cranks up the heat when I am out there, some kind of forced air would be better.

[Quinn]

I can see where it would be great undet tiled floor in the bathroom.

 

I check into hot water tube/heat in the concrete floor of a garage I am building. If I always wanted to keep the garage warm, it would be the way to go, despite the high cost. If I plan on just wanting to cranks up the heat when I am out there, some kind of forced air would be better.

 

I'd be afraid of using in a garage; there's a lot of weight on a garage floor if you're parking cars. I'd worry about crushing or pinching the underfloor piping.

[Shaman97]

I'd be afraid of using in a garage; there's a lot of weight on a garage floor if you're parking cars. I'd worry about crushing or pinching the underfloor piping.

 

If you're doing new construction, not to worry. The local FD has installed it in their apparatus bay (where the engines and trucks are parked) without incident, and it works fantastically. The hot water tubing is buried deeply enough in the concrete that it's not an issue. However, if you're looking at a retrofit situation, do something else.

[KMG_365]

You can see some pics of our retro-fit install here:

 

http://kmg-365.smugmug.com/gallery/617228_mRmrg#55435660

 

If you look on pages 8+9 you can see the heating elements getting stapled down right on top of the backerboard (which was floated above the wooden floor over a crawlspace) as we were putting down almost 1" thick Mexican Pavers in a 14" hexagon pattern there was enough thickness of tile to distribute the heat very evenly. We still get a few cold spots as the floor is warming up, but once it's been on for half a day it's pretty uniform. Leslie has to have bedroom windows open to sleep, so this way we heat the contents of the room and not the air. The master bedroom is a peninsula sticking off the house with three external walls and on the due north end of the house as well so it used to get REALLY cold in the winter. We need no other source of heat on that end of the house now! When it gets below 40*F for a few days on end, we close down all but one window and still if we leave the floor on high all day with the door closed, we have to open more windows to cool it off enough to make it comfortable enough to sleep. Insulation is the key!

 

For the existing tiled bathroom floors, I just stapled it to the subfloor underneath and added extra insulation below it to drive all the heat up into the floor. I've only got two strips under the relatively small bathroom, but I ran it under the mud shower floor tile as well and it's REALLY nice to step into a morning shower in the middle of winter and feel the warmth on your bare feet!

 

The strips only get to 80-90*F or so and I would worry about pyrolysis with a system in contact with a wooden floor that got over 110*F. For concrete that would be fine, I suppose, but I also don't mind not having to deal with the plumbing aspect of the install. The material is millimeters thick and the wires are easy to hide in the thinset.

[velomoto]

It may be enough to sufficiently warm the floor but will it be enough to adequately heat the entire house?

 

Radiant floor heat is only for a comfort factor. It's not intended to heat the home only a cold floor usually in a bathroom.

In CA there many homes built with radiant heat concrete slab floors to heat the entire home. In CO many of the high end homes use radiant heat in baseboards and/or under the subflooring. Radiant heat is also used to prevent ice buildup on drives of some of the uberexpensive homes at Vail, Aspen, etc. etc.

 

Pro's of radiant heating are:

- Quiet: no air blower

- Comfy: not much beats a warm bathroom floor in the morning

 

Con's

- Slow to warm so one needs to keep the heat running. With forced air one can allow the home to cool when away and the furnace can bring it up 5 to 10 degrees relatively quickly.

 

- Expensive to install. These systems aren't cheap.

 

- Need to install air ducts and blower if one also wants air conditioning.

 

- Very expensive to repair if installed in a concrete slab or if the ceiling is installed below the radiant heating elements.

 

For the most part, friends who have lived with radiant heat absolutely LOVE it. The single largest complaint I have heard is that it is expensive to use, and as I pointed out above this is primarily because then could not drop the temperature of the home during the hours they were away. One can certainly warm a garage with radiant heat, but it is important that the concrete slab is well insulated otherwise much energy will go to heating the soil beneath the slab.