making my radiant more efficient?

[wheelinguy]

When we built the house about 9 yrs ago we put staple up radiant tubing on the underside of the floor, I was curious if anyone had a method to make it transfer heat a little better?  I know that pex can be run in aluminum channels but is there something similar to help the onyx tubing?

[John Mc]

You did put insulation under your tubing, didn't you? That will help make sure the heat goes up through the floor, rather than down into the space below.

[wheelinguy]

Yes we put foil faced r-19 in, foil face up.  Just looking for a way to make it more efficient on the really cold nights.  Was wondering if anyone had experimented and come up with something that improved it.

[Corley5]

Larger circulating pumps 

[Holmes]

You can get snap on aluminum panels and staple them to the sub floor or extruded aluminum panels and screw them to the sub floor. If you have 5/8" tubing it will be difficult to find panels that size. What you have is called joist bay heating and it very slow reacting.  You should check your insulation, make sure that the ends of the bays toward the exterior are insulated with at least 6", more will be better also make sure the heat is not escaping along the sides of the insulation into the basement.  There is, was a radiant company in Vt. that sells an aluminum fin to put on the pipe . They say it helps deliver more heat.

[maanma]

What is above heating pipes? Gyproc, concrete, tiles, wood floor or what? Wood floor is an insulation.

[wheelinguy]

maanma, we had a laminate floor above the radiant before, now we have tile in the kitchen and jotoba (brazilian cherry) over the rest.  The wood is very dense and acts as a great heat sink, it along with the tile have made the floor better but I would still like to improve it.  I'm open to suggestions.

[711ac]

There are 2 types of these aluminum heat transfer plates for the exposed (staple up) radiant tubes. One is a thin (alum. flashing like) panel, the other type is an extruded, much heavier aluminum and will transfer more heat. I am not a radiant design guy but I did hire one for my project, and this is what I was told. Both types are about 3' long and you may have to remove some of your staples to fit these panels over your tubing, the panels can then be nailed, stapled screwed, etc and will hold up the tube. They http://www.nrtradiant.com/  spec' diferent panels in certain areas and I am very pleased. You'll need to know your tubing size, but they do sell this stuff and are not far from you (in Gardiner ME) and  good folks. 

[forest]

A different thought might be to use a combination of floor and radiators on the walls. I heat with the hot water radiators and they are the pipe with little metal fins and provide approximately a third what an eclectic wall radiator would provide. You could have perhaps one circuit for those cold times when the radiant floor heat wasn't enough. 

[wheelinguy]

711ac I tried to email NRT but was kicked back, I will try to call them later.  Forest I don't want to have to cut in to the existing system or make any major modifications, just looking into making it a little better.  Thanks for the ideas, keep them coming.

[John Mc]

Wheelinguy -

Are you looking to make your system more efficient (ie use less fuel), or are you looking to get more heat out of it (if it's not keeping up on those really cold days)?

Or maybe you are looking for something else... more even heating?  Faster response time?

Your goals may influence the answers you are getting. 

[beenthere]

What water temp are you sending out through the runs? And what is the drop in temp when that water returns? Seems that will tell you what the efficiency is for radiating heat in that run. 

Sounds like you are wanting more heat from your system, and tearing into your present system as forest suggests may be necessary.

I assume you are heating the water to the highest temp. possible. And also assume you are pushing as much water through the run as possible (and have purged all the air out of that run which is basic to your system).

[bandmiller2]

Wheeler,those staple up thin aluminum sections are quite costly.Its possible to get a roll of flashing and bend your own.I made a set of dies when I did mine and installed them in a small press brake.You could make them out of wood and use a vice or clamps to bend them to shape.two parallel 2x4's and a dowel or pipe on anouther board to press down.If I recall their should be an air space between the pex and the foil insulation,I used cellotex foam board with foil. Frank C.

[r.man]

Could you define costly Frank?

[Don_Papenburg]

You need to slow the water speed passing through the pex so that you are extracting at least 20*  Close your return valve a bit  at a time till you achive the temp.drop needed .I run my temp drop in the 20* to 25* range.  Water rushing through the pex will not have time to radiate heat into the room.
On wood floors I was told to keep the temp below 120* max incoming and out at 100* to 90*.  Tile floors can be higher ,but not realy needed.