Trying to Eke out a few more degrees with Radiant

14 years ago

Greetings, Happy Holidays to all...

Did a complete gut and remodel of our kitchen this summer and installed an underfloor hydronic system. Until this week, system heated room well. Winter seemed to arrive this week and I can't get much above 65 degrees (air temperature). Manufacturers site for my flooring (wood look laminate) recommend that the "surface" that the flooring is installed on is not above 90 degrees. Temperature sensor is reading 90 degrees.

The floor construction is 3/4" red oak (original 125 year old planking), in various places building felt to level the surface, then 1/2" plywood subfloor, foam underlayment and then the laminate. The sensor is on the bottom of this cross section. It is mounted in a 4"x4" area where the metal heat transfer surface was removed, thus the sensor is mounted directly to the bottom of the red oak planking. Downward heat loss is limited by 3.5" fiberglass batts between the floor joists.

Here is my question. With a 90 degree measurement on the bottom of the red oak planking, what might the temperature of the top of the 1/2" subfloor be? Is there some heat transfer loss through this cross section, OR does the whole floor eventually reach 90 degrees. Obviously where I am heading is whether I can nudge the slab sensor limit up a bit? I don't have any way to directly measure the temperature of the subfloor without pulling up the laminate. THANKS for all help

Sort by:Oldest

Comments (8)

wisehvac
14 years ago
The answer is yes usually the temp you want it is 110, 90 is low. try not to go over 125. What product did you use? did you go with viega, wirsboro or someone else. Did you use climate panels or stapple up. if staple up do you have a barrier between floors?
tmy23
Original Author
14 years ago
The tubing is 1/2" Zurn. The controls, valves I believe were a pre-packaged wirsbo that the HVAC installer put in. I fabricated my own heat transfer panels with flashing that I cut to length and pressed using a form made from a 1/2" piece of PVC screwed to a plank, with a "mating" plank that had 2 pieces of 1" furing strips screwed 5/8" apart. By simply placing a piece of flashing between the positive and negative forms, and standing on the stack, I was able to press a "U" shaped channel into the flashing stock. This was then stapled up to the bottom of the oak planks enclusing the PEX in the "U". It worked well. The flashing is sized to fill the entire joist bay from joist to joist. Then as said above, I put 3.5" fiberglass right up against the metal flashing. In terms of "barrier" do you mean the foam barrier that I put down between the playwood layer and the finished laminate? I used Unison 2 in 1.

So your saying I can raise the floor temp a bit?

thanks
Related Discussions
Just dug out a few potato plants
Q
Comments (14)
I agree, you definitely can not bake or fry the canned potatoes, they are for a different purpose. Just had some home fries for breakfast from canned potatoes, they were very good and super quick. Of course I am a mother of a 2 and a 3 year old so sometimes super quick is a huge benefit in our house and may not be in everyone else's house. I don't can all our potatoes, and we do two crops, one in spring and one for fall. So we keep baking and frying potatoes also. Our fall potatoes I do more for storage and will store in a mound in the garden through winter. In the summer I am using that space and don't have that ability. I realize that canning potatoes isn't for everyone, but canned potatoes serve a purpose that works very well for some depending on your cooking style and your family's favorite recipes. To each his own. So @Hobbiest, try some, you may find out it is not worth the bother for you or you may find it is a huge time saver and a great use of your potatoes.
...See More
Took a few pictures this evening while trying to water
Q
Comments (15)
Debra. WOIA does get special attention as I just love this daylily so much.It gets watered early each day when I go out after my paper.I take my 2 gal water can full of water with me and give it a good drink, then it gets water again in the evening in this heat.It geta a water soluable fertilizer once a week, too.Its in a big pot, and I will have to put it in a bigger pot or divide it maybe, this fall. Sarah. Thanks for looking and commenting. Julia;WOIA is blooming its heart out for me and had 8 big blooms when I took the picture, but only took a picture of the one bloom. Nancy;Wish you would please send some of that rain this way.We are really needing some rain here. Cindy. I like El Desperado, too, and it was faded a little too.I think most of them fades in this hear.Even Ms blackie keeps going from one shady spot to another,I guess to see if one place might be cooler. Kay: No, am not better yet with this knee.Just decided I was tired of not taking pictures and decided to go out and try again. I paid for it last night, but, lucky me had a couple super duper pain pills left for when I had broke my wrist and didnt take them all, so I took one of them last night,and it helped. Rita;Grant's play is a very pretty red,and I am like you.I like the bright colors.Even the oranges now,and I didnt like orange ones for awhile. Ms Blackie is tired from going to place to place looking for a cooler place to rest. Ellie; I cant believe that any one would not just love WOIA. I go out every few hours to look at it.I just think it is soo pretty and can't get enough of it.It has just had its last bloom on the first scapes and is now starting on the rebloom scapes and so far I have counted 7 rebloom scapes on it. I LOVE IT. Val, Yes, this WOIA truely must love the heat,as it is sitting in all day sunshine and always looks beautiful.Its in a pot, too, but a big pot and is fast filling it to the brim. Ms Blackie wears herself out when I am outside watering or taking pictures because she thinks she has to stay within a foot or two from me,and she hunts for shade to get in each time she moves to follow me. Maybe shes just so grateful that I took her in and feed her regular meals.She was a stray that came here about 7 years ago, just starving,and nothing but skin and bones,and she was so wild,I could not get close to her at all. I went in and only had some sliced ham in the fridge that a cat would eat, so I took a few slices and chopped it up small pcs,and took it out to her,and she would not come eat it until I got at least 15 ft from her, then she came and ate it.That went on for months and months,and each time I few her,I stayed a little closer to her, until finally she would let me closer. A few months after that,I was able to pet her.Now, she dont want me out of her sight.Shes just a loveable little doll. Jean
...See More
A few questions about radiant heat
Q
Comments (10)
Shaughnn covered everything. Agree with shaughnn. In each sentence, one could add a detail or a "but not if"; this does not change the overall thrust of what he wrote. If I had to work for Shaughnn, or if had to hire him I know I could talk and communicate about everything necessary. The majority of people experienced with heating cables would not think of mentioning the difference between an installation on a concrete slab or on a wood structure. Go figure. It makes a huge difference, and they don't mention it. Operating costs depend on Watts. More wattage, more heat, more power, more consumption, more cost, they are all the same things (wattage = heat = power = consumption = cost) as long as the building's insulation is effective. If you heat a slab that you own both sides of, and that you live both sides of, you get all the heat energy back as it acts as a radiator on both sides. If you heat a slab on grade, in a damp basement, you are heating Mother Earth and using (cold) ground water as the conductor (heat conductor) to accelerate the heat transfer into the Earth. Not as good. This is where a thermal break is a good thing. If you heat a slab on grade, and you think it's dry and won't conduct as much into the Earth as a damper comparative slab, you are right but you will still spend a lot to heat the slab, and most of the heat you are paying to produce will go into the ground. "Most" is how much? Since it's a sink, in thermal conductivity terms, it's way way more than half. As shaughnn wrote, a question about brands will never get any specific answer, as a heating coil is a heating coil, as dumb and simple as a toaster. They are all the same as far as heating goes. In a toaster, the heating coil is "a heating coil" and nobody asks if one or another is better or the best, in a toaster. Same thing with a heating cable in a floor heating system. "It's a toaster" is a common phrase in certain engineering circles, meaning if you're consuming power, you are generating heat. It also means that's the end of that analysis, move on to the next subject, there is nothing more to ask about here. Power = heat. Yes one can put heating coils under tubs / showers, near toilets too, and a little bit into cabinet space (but this is best when you know how to plan for heat transfer and air movement, and not advisable to the average bear, or else you get a very warm box that thwarts your goals because you have to reduce heat to compensate for the box heat, or you have to leave the cabinet door ajar, or drill holes somewhere, or...) Mats yes. Loose cables can be pulled off a mat if needed. Buying a long loose cable is just a few extra days work, nothing serious if you have all the time in the world and nothing else to do. To find out if he / she got it right, the average person reading about heat cables needs to post about "watts per square foot" they might want to have, and tons of information about their slab or subfloor, and the cork or other insulator or membrane as a heat break between the cables and the slab or subfloor, or about the insulation under the subfloor or about their building envelope. Although it IS possible to use electric cable radiant heatings systems as a primary heating source for a room, the average homeowner should not try to achieve this after a bit of internet reading. There are so many reasons why you may be less than satisfied that it's best not to get your hopes up. plumberry asked for confirmation that electric is the way to go. I guess this means "electric and not a hydronic loop" but this was not specified. Since we received no information from plumberry about anything, the answer is NO, not yet, not enough is known about plumberry's situation. But it is true that electric is a great way to warm one room. . Here is a link that might be useful: A thread that shows all the problems and ends in a Thank_You
...See More
Upstairs too warm, trying to sort out causes and find solution
Q
Comments (29)
Follow-up: I got a full audit with blower door test, which was awesome. Found a number of prominent leaks, some of which I'm plugging myself (supply registers, outlets, windowframes), some of which are for future consideration (basement), and some were plugged when I got my attic sealed and insulated yesterday. It turned out that after my recent roofwork, there were some areas of the attic that really needed to be sealed and insulated, so I am I happy I got that done in any case. Now we will see how the house performs on a hot day, assuming we ever get another one around here. Next on my todo list is probably my horrible supply ducts in the basement for the upstairs supplies (undersized, uninsulated and leaky). But we'll see how things go in the meantime.
...See More
wisehvac
14 years ago
well when you make your own heat trasfer plate your only lookig for trouble it may not be working right ...... google radiant barrier, insulation isnt enough. but you should be able to go to 120 no propblem check with the manufactors specs.
freedee
14 years ago
One thing you might want to rule out is having air bubbles stuck in one point of the tubbing. If it used to work well them it became less effective, it could be because air bubbles formed. They weren't there when the system was first installed. They form latter. water breaks down into the two gases that they are made of. I think that's how it works, but I'm not sure about that part. I am sure that I had areas of my system that stopped working. I raised the temperature a lot. It didn't work any better. I bled that run of tubbing and it worked better.
chrisny
14 years ago
I see a bunch of issues (no experience with radiant myself).

Seems like the foam is adding a layer of insulation so the temp reading for you sensor is probably higher that the laminate temp. Based on that I think it would be safe to raise it a bit.

I also wonder about the ability of radiant to work in such a non conductive medium (wood/foam). I know it can be made to.

Are the loops laid out/spaced correctly, who engineered (or lack thereof) the system, is there enough capacity/zones
tmy23
Original Author
14 years ago
The HVAC installer who did the piping to the radiant panel, and installed the sensors and programmed the system told me what size tubing to use, how to run, etc. etc. As I was saying up earler in this post, it seems the 1 1/4" wood and then foam underlayment, would prevent 100% heat transfer, so the top of my floor might be cooler. I wish I had thought of drilling out a little hole in the floor to put the sensor right up against the laminate. I raised the floor temperature max from 90 to 95 degrees and the room air temp is now up to 67 with an outside temp of 36 degrees. I am tempted to take it up another 5 degrees to 100 which should get me close to 69-70 with an outside temperature of 30. Again, I just didn't want to screw up the flooring, but I don't think the floor is getting up to 100 on the top side?
freedee
14 years ago
If you could run some tubes up a wall in that room, that could help. Also, did you insulate the part of the tubes that are not under the floor? If not, it sounds like the water could be losing all it's heat (radiating) in areas other than that room. When it gets to that room, it is insulated by the foam in the floor and not losing or radiating heat.
zl700
14 years ago
On average insulated homes with kitchen cabinets and appliances consuming a % of the floor available in kitchens for radiant it is not uncommon for the need of supplemental heat or a connecting room beefed up to cover the difference.

The design/heat loss calcs would have disclosed that.

Trying to Eke out a few more degrees with Radiant

Comments (8)

wisehvac

tmy23
Original Author

Related Discussions

wisehvac

freedee

chrisny

tmy23
Original Author

freedee

zl700

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Trying to Eke out a few more degrees with Radiant

Comments (8)

wisehvac

tmy23Original Author

Related Discussions

wisehvac

freedee

chrisny

tmy23Original Author

freedee

zl700

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

tmy23
Original Author

tmy23
Original Author