Hi,

I have a question for anyone having actual experience with a floor based
radiant heat system.

I'm planning on installing a hydronic between-the-joists system. It will
use PEX fastened to the underside of the subfloor. The person who'll be
helping me with the install, and has installed these systems before says
that the aluminum heat diffusers you can apply along with the tubing are
useless, especially if you're using water heated to about 100F. I've been
reading Siegenthaler's book on the subject and he's absolutely in favor of
their use.

Does anyone have any comments? My biggest concerns are 1) will the system
be more efficient and able to react faster when needed, and 2) will you get
hot stripes on the surface of the finished floor without them possibly
leading to premature degradation of the hardwood flooring finish.

FYI, I plan on using mostly hardwood flooring (some tile). Subfloor is 3/4"
advantech. House is mostly one floor with a full basement. Joists are 16"
on center.

Thanks for your input.

guessing: your local answer may be directly related to your climate and
temperature swings of the basement.
nice cutaways at:
http://www.healthyheating.com/Page%2...adiant_sys.htm
no mention of the diffusers at:
http://www.neoheat.com/expert-zone/w...ge-design.html

Just Me wrote:
Hi,

I have a question for anyone having actual experience with a floor based
radiant heat system.

I'm planning on installing a hydronic between-the-joists system. It will
use PEX fastened to the underside of the subfloor. The person who'll be
helping me with the install, and has installed these systems before says
that the aluminum heat diffusers you can apply along with the tubing are
useless, especially if you're using water heated to about 100F. I've been
reading Siegenthaler's book on the subject and he's absolutely in favor of
their use.

Does anyone have any comments? My biggest concerns are 1) will the system
be more efficient and able to react faster when needed, and 2) will you get
hot stripes on the surface of the finished floor without them possibly
leading to premature degradation of the hardwood flooring finish.

FYI, I plan on using mostly hardwood flooring (some tile). Subfloor is 3/4"
advantech. House is mostly one floor with a full basement. Joists are 16"
on center.

Thanks for your input.

Just Me wrote:
Hi,

I have a question for anyone having actual experience with a floor based
radiant heat system.

I'm planning on installing a hydronic between-the-joists system. It will
use PEX fastened to the underside of the subfloor. The person who'll be
helping me with the install, and has installed these systems before says
that the aluminum heat diffusers you can apply along with the tubing are
useless, especially if you're using water heated to about 100F. I've been
reading Siegenthaler's book on the subject and he's absolutely in favor of
their use.

Does anyone have any comments? My biggest concerns are 1) will the system
be more efficient and able to react faster when needed, and 2) will you get
hot stripes on the surface of the finished floor without them possibly
leading to premature degradation of the hardwood flooring finish.

FYI, I plan on using mostly hardwood flooring (some tile). Subfloor is 3/4"
advantech. House is mostly one floor with a full basement. Joists are 16"
on center.

With hardwood floors you want to try to equalize the heat distribution
underneath the floor. Hardwood floors expand and contract with
temperature and humidity and the radiant amplifies the expansion and
contraction. The hotter areas will have larger gaps and that can tend
to look off. Use the diffusers.

R

Just Me wrote:
Hi,

I have a question for anyone having actual experience with a floor based
radiant heat system.

I'm planning on installing a hydronic between-the-joists system. It will
use PEX fastened to the underside of the subfloor. The person who'll be
helping me with the install, and has installed these systems before says
that the aluminum heat diffusers you can apply along with the tubing are
useless, especially if you're using water heated to about 100F. I've been
reading Siegenthaler's book on the subject and he's absolutely in favor of
their use.

Does anyone have any comments? My biggest concerns are 1) will the system
be more efficient and able to react faster when needed, and 2) will you get
hot stripes on the surface of the finished floor without them possibly
leading to premature degradation of the hardwood flooring finish.

FYI, I plan on using mostly hardwood flooring (some tile). Subfloor is 3/4"
advantech. House is mostly one floor with a full basement. Joists are 16"
on center.

A commonly used system in my area is to suspend the tubing between the joists. It is critical that the joist cavities are insulated with reflective insulation. Haven't used it myself, so I'm not exactly answering your question, but this is what I am hearing from our plumbing supply house in Duluth, MN. If it works here, it ought to work anywhere.
R

"Just Me" kenk228@adelphiadotnet wrote in message
The person who'll be helping me with the install, and has installed these
systems before says that the aluminum heat diffusers you can apply along
with the tubing are useless, especially if you're using water heated to
about 100F.
Does anyone have any comments?

Heating engineers spent a lot of money on R & D to come up with the ideal
method of heating the floors. What has your friend done for testing? Use
the diffusers.

#1. if your water is only going to be 100 degrees, don't bother.
#2. if you don't "radiate" the heat out from the tubing, what's the point?
the aluminum plates are essential for this type of install.

--
Steve Barker


"Just Me" kenk228@adelphiadotnet wrote in message
...
Hi,

I have a question for anyone having actual experience with a floor based
radiant heat system.

I'm planning on installing a hydronic between-the-joists system. It will
use PEX fastened to the underside of the subfloor. The person who'll be
helping me with the install, and has installed these systems before says
that the aluminum heat diffusers you can apply along with the tubing are
useless, especially if you're using water heated to about 100F. I've been
reading Siegenthaler's book on the subject and he's absolutely in favor of
their use.

Does anyone have any comments? My biggest concerns are 1) will the system
be more efficient and able to react faster when needed, and 2) will you
get hot stripes on the surface of the finished floor without them possibly
leading to premature degradation of the hardwood flooring finish.

FYI, I plan on using mostly hardwood flooring (some tile). Subfloor is
3/4" advantech. House is mostly one floor with a full basement. Joists
are 16" on center.

Thanks for your input.

Steve Barker LT wrote:
#1. if your water is only going to be 100 degrees, don't bother.
#2. if you don't "radiate" the heat out from the tubing, what's the point?
the aluminum plates are essential for this type of install.

#1 and #2 seem to offer conflicting advice. What are you recommending?

R

So I've seen these diffusers which look basically like a piece of sheet
metal with a channel formed to fit the PEX tubing. My guess is that you pay
a pretty hefty premium for the form-fit. What about just fastening flat
metal to the underside of the subfloor, then fastening the PEX to the
metal.. It may not be 100% as efficient as the formed diffusers, but if you
get 80% of the value for 20% of the cost it might be worth considering.
Also, I would guess that a flat piece which is *between* the PEX and the
subfloor will reduce striping *more* than the form fit diffusers. Just
seems intuitive to me. Anyone have an opinion?

"RicodJour" wrote in message
ups.com...
Steve Barker LT wrote:
#1. if your water is only going to be 100 degrees, don't bother.
#2. if you don't "radiate" the heat out from the tubing, what's the
point?
the aluminum plates are essential for this type of install.

#1 and #2 seem to offer conflicting advice. What are you recommending?

R