My current plan... Staple up 1/2" pex-al-pex (already have), make some plates from al sheet (.016), dedicated water heater as heat source. Floor cverings will be floating hardwood, ceramic tile, and some carpet.
Questions: Joists are 16" on center, should I have two runs per joist or would one be sufficient? Is the aluminum sheet going to provide any benefit? How thick are the plates you guys talk about?
My goal is not so much heating, just like the warm floors.

8" OC for the staple-up is probably the only option... 16" OC staple-up and you'd have to add supplemental heat for anything cooler than a summers night.

As for transfer plates, don't mess around. Just go and buy Thermofins from Radiant Engineering and be done with it.

Don't forget to insulate like heck below either, you really have to squeeze the heat up.

Constantin! This is supplemental!

Sheesh... thermofins for supplemental is like buying an RV for your morning commute!

.016 grade is ok, but you need to be careful to make grooves that will seat well with the tubing. they also need to have as much contact with the subfloor as possible (staple the bejeezus out of them).

You do definitely want 2 runs per bay for even floor temps above.

If you are really only doing floor warming, you probably don't even need the plates at all.

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Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

Rob, I commute to work in my Winnabego (?) all the time!

But seriously, I doubt that a DIY plate manufacturing operation is much cheaper than buying pre-made stuff that fits the tubing perfectly. Surely the price of the Thermofins isn't rapacious, is it?

Besides, being a creature of comfort, I'd strive to make the system as efficient as possible to warm my toesis.

the price is very different. veeery different.

If he is using a water heater he does probably need plates even for floor warming, but he doesn't need heavy gauge plates. That would be total overkill.

------------------
Northeast Radiant Technology, LLC
-=RFH Design, Supply and Consultation=-
RPA certified Radiant Designer
http://www.NRTradiant.com
rob@NRTradiant.com

I gotta agree with Rob,If it's just about taking the chill off the floor than thin plates will do the trick just fine,(Sorry Dale I can't believe I said that myself)

However if it's good track why not use the radiant as the primary heat source?

Thanks guys.
I'll stamp the plates using a pipe the exact size of the tubing so there will be good contact.
I have some reflective insulation, is it effective in the long run? I read that after a while dust pretty much eliminates any benefit. Is it worth the cost to buy more?
It would be my primary heat source but I already have a very efficient heat pump. I may add a HE to replace the electric emergency heat (currently disconnected).
I'm also going to change from all electric to some NG.
If I use a water heater and a HE as the heat source(s), is better to get the DHW from the tank with the radiant from the HE or vice versa?