DIY Hydronic Floor Heating

[Mobile Master Tech]

Concerning thermal transfer compounds, I saw a computer forum where a guy tested various kinds, from high dollar to toothpaste! The toothpaste performed nearly as well as the most expensive for quite a while-it dried out and lost much of its conductivity, but was still better than none at all.

The Blue Ridge Company is the best place I found to order PEX. They have 1/2"
American made RHT oxygen barrier PEX-C(which I used even though I have an open system), which is currently 30 cents per foot with free shipping, and lengths from 300ft to 1000ft per roll. I tried 4 brands of PEX including A,B & C crosslinking methods and theirs was noticeably easier pulling, more flexible and more kink resistant than the others. PEX A is supposed to be more flexible, but the brand I tried wasn't as good as the RHT, plus the outside was "grippy", making pulling/handling more difficult.

[Mobile Master Tech]

New projects? Yup-firing my energy utilities! Even with 4 people, 2 businesses, electric clothes dryer, and shop equipment in the house, I've gotten my daily KWH use down to 17-21 without AC and 27-33 with my new 23 SEER Nordyne AC set on "meat locker", including a couple of parties with 40 people present. All my light fixtures except one are now CFL or LED. Costco just came out with a 3 pack of great LED bulbs for $20, and they work great and are dimmable.

That usage, my friends, is within the capabilities of an off-grid "prepper" solar PV system with hybrid heat collectors feeding heat to a hacked GSHP that uses boreholes around the house to raise all the surrounding dirt temperature enough to increase the GSHP efficiency-Passive Annualized Heat Storage.

I want off-grid capability, and my utility only pays 2.5 cents per KWH for surplus capacity right now. If they change, I may go grid-interactive so I can sell to them.

Oh yeah-I bought a Mazda Miata that I plan to convert to electric!

[Daox]

Sounds like you have some fun projects coming up! Thanks for sharing.

[Mobile Master Tech]

Forgot to say that my piping choices are for non-buried use. For underground, I wouldn't use PVC/CPVC-it cracks with ground settling as it gets brittle. Use copper, PE, PEX, etc. If you can just unroll a stiff coil in one direction inside a trench, then PEX might make sense. It's just too hard to manipulate in the larger sizes for anything else.

[AC_Hacker]

Originally Posted by Mobile Master Tech

They have 1/2" American made RHT oxygen barrier PEX-C(which I used even though I have an open system)...but the brand I tried wasn't as good as the RHT, plus the outside was "grippy", making pulling/handling more difficult.

MMT,

This sounds exactly like what I am looking for. However, when I went to THIS LINK, there was no RTH PEX-C.

Did you make a typo or did they discontinue the above mentioned product?

Best,

-AC

[Mobile Master Tech]

It's there, just not described as PEX-C on that page. The one that lists "electron beam processing" is what I used, and once you click on it the description shows PEX-C (the most environmentally friendly kind).

I think I bought it for 23 cents/foot-it's gone up. The PEX-B 900ft roll is on sale for 24 cents/foot. Probably good, I just haven't tried it.

Craig

[48flh]

hi everyone new to the site:

[michael]

Checking in after a long absence. I'm working on a new house (1200 SF). The plywood subfloor is installed, and I'm just beginning work on the radiant system which will be in a 2" concrete slab. Here are a few of the many photos I've been taking showing the joists and girders, the subfloor, and a look at the front porch slab in which I brushed out simulated grout lines to give it the look of the tile that will be inside the house.

I just went back and skimmed through all the posts in this thread hoping to uncover whether or not any other poster has looked at Vanguard Pipe & Fittings Ltd. - Pex, Hydronics, and Geothermal Products Manufacturer. I stumbled across the site while looking for pex and parts, and they have a link to installation manuals that seem pretty good to me. One details doing the calcs for and installing a radiant floor in slab on grade, on plywood, in the joist spaces, any way you can think of. Another details how to weld HDPE pipe. All the manuals and tutorials can be found in the section of the site titled "Download Centre." If it's already been mentioned here, then I offer my apologies. A couple of links are below.

Once the pex is installed on the plywood, I'll add photos of the progress. I'm having way too much fun with this project.

The first link is for the installation manual, and the second for the download center where the manuals are found.

http://www.vanguard.ca/guides/Hydron...n%20Manual.pdf

Vanguard Pipe & Fittings Ltd. - Pex, Hydronics, and Geothermal Products Manufacturer

[AC_Hacker]

Originally Posted by michael

...I stumbled across the site while looking for pex and parts, and they have a link to installation manuals that seem pretty good to me. One details doing the calcs for and installing a radiant floor in slab on grade, on plywood, in the joist spaces, any way you can think of...

This looks to be a really great resource you have linked to... very well presented.

One of my favorites is the Watts Radiant computer program called RadiantWorks, it's free. It appeals to me because it is so easy to do "what ifs".

However, your resources should work just great for you.

Good luck on your project and be sure to keep us updated as you go along, we all want to see your progress.

BTW, have you made a decision as to what method you intend (oil, gas, electric, firewood, solar, geothermal, air source heat pump,etc) to use to heat your hydronic water? That can make a big difference in your design.

...and while I have your attention, what is your zip code? I can do a degree day calc for you.

Best Regards,

-AC_Hacker

[michael]

Zip code 95460. The house has energy compliance heat loss calculations to predict how it's supposed to perform. They were part of the permitting process, and they predict 17k BTU/hr loss in the worst case. As an aside, I have professional heat loss calcs for my current residence which I built 25 yrs ago, and I'm monitoring our heating system in order to calculate the actual energy required to maintain the comfort level of the house. It will be interesting to see how they compare. We have a mild climate stabilized by the proximity of the Pacific Ocean and not hard on a heating system.

The plans call for a geothermal heat pump to provide space heat, but that's another story.