pretesting the feel of radiant heat?

heatless

I ran some pex thru the joist in my house, then hooked it up the my tankless via the tub/shower. when some take a bath this should heat the floor giving us radiant heating. Well it doesn't. Can give me some idea how I can produce the feel of radiant heating . so I can convince my wife it is worth the upgrade from our floor heater.

 I ran 1/2 pex thru the joist at roughly 8" on center, used the clip to attch it directly to the subfloor. the subloor is just 7/8 thick wood and even though the pipes heat up. I feel nothing thru the floor? The water heater is set at 140. Any ideas.

Mark Eatherton

Got insulation??

Gotta have it below the tube. Probably ought to use some foil backed, and leave a gap of air between the reflective and the tube, and seal the ends so the heat doesn't leak out the ends.



Better yet, find some extruded aluminum heat transfer plates, and try it again.



If your wife needs convinced, send her here!



ME

KevinCorr

Is it a circ loop.

Do you have a circ pump on this loop?

If it is just one pass on the way to the bath it will not have time to heat the floor.

Timco

staple up

I used the extruded aluminum plates with 1/2" pex on 8" centers, and that is under 7/8 fir sub and backer / tile and the floors can get up to 80*+ easy. Used standard staple-up insulation in rolls from Depot. Heater is 7 gal electric at 140*. When yours works correct, you may end up with less hot water in the shower than desired because of the heat transfer. does not sound like a very good way to get radiant floors. Kev made a great point as well...one pass will not do the job.



Tim

Unknown

Thought you knew better than that Tim,,,,,

even a Canadian wouldn`t expect much from that setup!!!  ;-)

Ex Maine Doug

Wood is a lousy radiator

under a bathtub.  My clawfoot tub is warmed by the radiant floor which is polished concrete with closely spaced tubing under the tub area.  If you can get access to the cavity around the tub, perhaps from other side of the back or faucet wall, you could run some tubing around the tub. 

Paul Pollets

Why not...

...get her an electric blanket?

ScottMP

Unless you have kids

And the kids take a 45 minute shower ,.... you will not run the floor long enough to transfer heat thru the wood floor. Even a tile floor wouldn't heat up in that short amount of time.

Just put the radiant system in and your wife will love you.....

By the way ... maybe hooking it up to the the heat in the rest of the house might make it work .... a little

Scott