hydronic (underfloor hot water heat

[Nat]

I'm building a new house and I want to use under floor hot water for heat. The local gas company will install 500 feet of line free and will give me 550.00 rebate to use on appliances, so I'll have a water heater and another water heater for the underfloor heat. I am going to use PEX piping and will install a manifold with a valve to each zone so I can adjust it after starting it up. I need to find the heat transfer plates, the al. pieces that help transfer heat to the floor. Does any one know where to find them? I've been told that they really help in heating the floor by pros, and been told that they aren't needed by others. Any imput?
Thanks, Nat

 

[keeney]

From what I found out:

1: In a staple-up application where you are putting the tubing under a plywood sub-floor, the aluminum plates are about the same heat transfer as using twice as much tubing.

2: Using twice as much tubing is actually cheaper!

3: When the tubing is embedded in a concrete or gyp-crete slab, the transfer plates are generally not used.

I used the aluminum plates under my bathroom floor in a staple-up application. I didn;t want to add thickness to the bathroom foor by putting the tubing under the tile. I really wish I would have put in even more tubing and more plates. I have to run the water to that zone at about 160 degrees to get that nice toasty feeling under the feet - a standard water heater might not go that hot!.

For general heating, the typical 8-12" spacing will probably suffice.

- Rick

 

[kayssupply]

How big is your house? A common BTU output for a hot water is 40,000 btus. That won't heat a very big house. It is more for an apartment.

 

[js5020]

Nat, I have a 2500 sq ft ranch with this type of heat I used the plates it's great. I was concerned about the hardwood flooring being cold in the winter and the effects of the heat system on an all wood floor, no problems encountered. I used a Bock oil fired hot water heater about 50 gal one, so I spaced the tubing at 8 inch centers 2 runs in a 16 inch joist bay, I used the plates I got them from the same place I got the other stuff. I also have the tubing in concrete no plates needed here of course just make sure you restrain the tubing from lifting and take your time with the concrete so you don't damage the tubing. I kept it simple 2 zones no fancy pumps or other stuff, works great and didn't spend a fortune.

 

[Red_Dog]

Sounds like a fun project that will reap some great comfort benefits down the road. Hopefully Murph (Thcri) will chime in on this thread with some additional knowledge. He owns his own heating company in MN and has a great deal of knowledge on hydronics. Personally, we used hydronics in our lower level of the house and our garage/workshop. I'm not sure about the BTU loads that are required in NC, but if you need to go with a larger heat source, I would put my 2 cents in on looking at Munchkin boilers. We have been very satisfied with ours and it's efficiency. It's a fully condensing, fully modulating unit from Approx. 40,000 BTUs up to 140,000 BTUs. If budget allows, I would also highly recommend looking at hyrdronics for your garage or workshop.

Good luck and have fun with the project.

Matt.

 

[jdmar]

Do a search on radiant floor and you will get a ton of info. I am at work and can't remember the name...but.... There is a company that makes a combined subfloor/aluminum channeled board. It is about 1.25 inches thick...and I am sure it is expensive but may work great.

Peter

 

[jdmar]

Try looking at Warmboard they make a combined subfloor with the aluminum lined channels already in place. Seems like a great do-it-yourself set-up.

We are planning a new home here NE Ohio) and would love radiant heat. But all our local builders say it will ADD over $10 per square foot above a regular forced air system. I know you still need ducting and a blower for A/C but this seems VERY expensive to me....does this seem right to you pros out there??

Peter

 

[rlw]

These two sites have good info on radiant heat:
RadiantDirect
RadiantCompany

I purchased some of my supplies from the second link when putting radiant in my workshop floor.

I'll second Red Dog's recommendation on Munchkin boilers. I just replaced the water heater I was using with one. It's an awsome unit. The Munchkin takes very little space - I got their newer model (T80M) that hangs on the wall. If you decide to go the Munchkin route for your heat source, you might want to get a price quote from these guys - they were nearly 500 bucks less than any other quotes I got.

 

[dmccarty]

Nat,

Are you on a crawlspace, basement or slab?

Do you already heat with gas or do you like the heat from gas vs heat pump?

Are you going to have AC in the house?

What is the square footage of the house?

Our new house is on a slab and we where going to put in radient heat but it was to expensive for our application. Some of the literature I was reading said to minimize the number of zones in the house since more zones cost more money and did not have much effect on the heating of the house. The heat would try to equalize across the house and the extra zones did not make much difference. I'm not sure if this applies in a house not using a slab.

You might need more than 500 feet of PEX depending on the size of your heated space.

The state of NC give solar credits for hot water generation. It might be worth it for you to put in solar panels to generate some/all of you hot water to heat the house.

Later,
Dan

 

[heehaw]

manyyears ago, over 20..one winter day, the temp was about 10F...and i went into a building where a guy raised birds..it was warm and very comfortable inside, and looking around, i couldn't find a source of heat. when i asked about it, he took me to the water heater, where 2 orange natural gas pipes were coming out of the concrete next to the gas water heater: he had just used the orange pipe that is normally used for natural gas around here, and put it in the slab when he built the building, and uses the water heater, with a pump thats controlled by a thermostat: and it worked great. i don't know about a comparison of heat exchange between the gas pipe and the pipe designed for this purpose or the price difference, but its an alternative.
heehaw