Radiant floor heating on pier foundations

[GitcheeGumee]

We are planning to construct a small cabin across the highway from Lake Superior, using radiant floor heating throughout the first floor.  We also plan to use pier foundation construction, both to reduce concrete usage and because the cabin will be adjacent to a high wetland.  

Are pier foundations and radiant floor heating compatible?  If so, could you point us towards an online or paper resource to read about how they are compatible?  We assume that more attention must be paid to the construction of the structure below the radiant floor but are having trouble locating info on combining the two building methods.

Thanks.

GitcheeGumee

[glenn kangiser]

I know of a couple of ways to do this - one uses expensive 1 1/8" ? plywood panels with the tubing grooves routed into the plywood then your floor goes over that.  It could be used over a pier foundation.

There are also aluminum pressed plates to support the tubing under the floor which I think would be much more cost effective.  In either case you would insulate under the tubing to prevent heat loss.  Many like to put something under the insulation to help keep it in place and keep small creatures from making their home there.

http://www.pexheat.com/catalog/index.php?cPath=20008_62

http://www.pexheat.com/
Radiant Floor Heating Installation Do It Yourself Radiant Heating Pex Tubing Pex Plumbing

http://www.radiantdesigninstitute.com/page2.html
Radiant Heat Index Page

[GitcheeGumee]

Thanks!  That will be a great help.

GitcheeGumee

[glenn kangiser]

No problem -- and I forgot to say --

Welcome to the forum.

The second site tells of a relatively cheap way to use a tank type gas water heater as your heat source.  Most other types of standard water heaters don't work near as well and they do not recommend tankless heaters.  They can be made to work but seem to be more problematic.

[builderboy]

Glenn, would that be a separate tank from the hot tap water supply?

[glenn kangiser]

For a small system this company was using the same tank.  The PEX does not need the oxy barrier - normal drinking water quality PEX.  Here is pretty complete instruction from them.

http://www.radiantdesigninstitute.com/page62.html

Also in praise of regular tank type heaters.

http://www.tesmar.com/html/in_praise_of_water_heaters.html

[JRR]

Folks who are lucky enough to have well insulated homes ... and have comparatively low electric rates can have the simplist water radiant heating systems.  Fuel fired hot water heaters have inherent loses due to high fire requirements (to prevent burner box corrosion) ... not a problem for electric heaters, as they can operate near the desired final temperature ... this means high-efficiency.  And electrics require no combustion vents.

The heating water loop(s) should always be TOTALLY separated from drinking water supplies ... only then are you absolutely sure of no cross-contamination, which can be deadly if anti-freeze is added to the heated loops.

Replacement electric water heater elements are available now in 15K BTU units.  Two of those in a small water heater tank ... thats a lot of output!

Because of the lower costs of electric heaters, one should consider making each heating loop/area a separate system .... separate heater, pump, controller, etc.  Can't be any cheaper, simpler, and safer than this .... and because there are no big bucks to be made by some contractor on this simple low-cost scheme ..... this will not be acceptable in areas of the country where the "Man" has already placed his hand on local codes.

[scottb]

do not use hot water supply to heat floor. use seperate systems. no, warm stagnant water  i.e. legionaires disease http://www.radiantec.com/ has great downloads.

[scottb]

great downloads here http://www.healthyheating.com/  and think of passive heated shower stall http://www.sunfrost.com/efficient_shower.html