DIY hydronic underfloor system

I am researching on if it is possible to build a hydronic underfloor heating system from common materials. I was thinking about purchasing a medium size water heater or maybe 2 if it needs it, water pump, and about 1000 feet of tubing, maybe pvc, or even your higher end common garden hoses as they dont have much insulation to contain the heat in the hose. and it isnt like the lines will be under any serious pressure. I am on a 4' crawlspace now, and I am getting ready to install insulation. The joists are 16" apart. The commercial stuff is way over priced if you have researched you can pick up a water heater for under 150 and a commercial smaller boiler will run 2000. also the pex hosing runs about 10 dollars a foot, your most expensive hose isnt 30 dollars for 50 feet. I have central air now that works fine, its just the floors are rediculously cold. I live in NC. Any help is appreciated.. Thanks

Dukeofnc, welcome to the forum. Your plan sounds sound. What is it you are asking help with?

I was wondering if this sounds like it would work well. I am trying not to dump 10k into a radiant system. And I have never seen one in person or the components used. But looking online at a few sites I have seen where water heaters were used, and I am not sure if they work properly for this application, also the hose, or tubing. The pex tubing that is suppose to be used looks alot like a garden hose. I was also thinking about running PVC as it is cheap too. I would think the hose would be better as I can run it between the joists in a snake pattern because it is so flexible. I am not wanting to waste 1000 either if it isnt going to work correctly. I was hoping to get some answers from people that have experience with this stuff. Will the PVC or a garden hose distribute heat well? or is there another inexpensive hose/tube that would work better other than the PEX? Will the water heater work for a heat source on a 1000 feet of tubing and would a smaller tank 20 gallon or 50 gallon tank be better? Should I split the tubing and drop maybe 2 20 gallon water heaters in the system or would 1 be sufficient? How large a pump should I use? I was thinking the smaller the better. any help is appreciated.

Post edited by: dukeofnc, at: 2008/02/23 18:13

I know this is an older post, but since I was out looking for info, I thought I would throw out a few ideas on the topic.

First, if you want to try DIY hydronic, at least use quality tubing, like PEX or PEX with aluminum core. We did our entire house with floor hydronic for roughly the equivalent cost to forced air, but of course we had to do the installation. There are a few reliable DIY radiant floor suppliers online, and ours was very helpful, and quickly sent replacement parts for damaged items. I am not here to endorse them, but if you ask, I will give you the contact info. We did a staple up install using aluminum heat distribution plates that we fabricated ourself onsite. I read a few studies funded by the DOE that claimed this was the most efficent way to go. I would suggest that if you do go this route, put something slippery like tyvek between the PEX and teh aluminum, so that when the PEX expands each cycle, you don't hear the creaking sounds.

We used a 50 gallon high efficiency propane water heater as teh heat source in the house, and a 40 gallon unit in the shop. In hindsight, these units are perhaps not the best choice for this application. Our propane costs are through the roof the last two years. We are looking to change the system over to a boiler in the house, and probably electric HW heater in the shop, since we are putting up a 9Kw PV array.

I will start a new thread with my questions, but my hope is to find some suggestions regarding boiler selection and installation.

I really do not like to bury any piping under a slab I cannot have access to if possible
http://www.masterplumbers.com/plumbviews/2000/ plasticfailure.asp