[Greenbuilding] staple up radiant

[Niko Horster]

HI Brian,

Staple-up radiant is done a lot. It works o.k. with wood floors somewhat
better with tile or stone covering. The issue is that in order for adequate
radiation to occur through the rather insulating covering of wood (or
subfloor/wood/carpet or area rug sandwich) you must run the supply
temperature to the floor at a much higher level than in a slab application.
I.e. around 120 - 140F rather than 90-110F. This brings a couple of issues
along: 

Higher fuel bill, because you have to expend more energy to heat the water
and do not have the savings that occur (at least in modern heating system
designs) by returning cooler water to the boiler and possibly even reaching
condensing mode in the boiler (if it is designed as such a unit)

Wood does not in general appreciate a lot of back and forth between cool and
warm. I would therefore make sure that the loops for your wood floor have a
constant circulation design that mixes the temperature to adequately supply
the needed water temp.

Then make sure you insulate well underneath and install the tubing with
aluminum fins to increase contact area. This will help you lower supply
temperature. 

I have heated an ash floor on sleepers over a slab that runs at a supply of
120F all winter long without much wood movement for almost a decade now in
VT. 

Good luck.

Niko Horster