Hot Water Radiant Ceiling?

iced98lx · February 2021

TL; DR: We have baseboard heat in our home, we are heating ~4500sqft with it. It works fine. All copper, installed in 1978 and starting to fix some seepage/pinhole leaks. I don't believe any sort of water filter/conditioner has ever been used. Boiler is also from 1978. House is 2x6 framed with decent windows which we do plan to replace.

House has drywall issues, a trusted drywall contractor says it'll be more expensive to fix them vs me taking it all down and him putting up new, especially since we want a smooth finish.

I am going through doing heat loss calculations right now since we want to be ready to replace the boiler if something were to go catastrophically wrong so we'll know more about that shortly.

Generally, I know radiant ceilings haven't gotten a lot of love in the states, especially since the days of embedding resistive wiring in the plaster ceilings. I would like to do away with the baseboards since I feel like we're about to start replacing a lot of connections and probably covers for them anyway. I'd prefer of course to do floors and we do have access to below (the house is built on engineered floor joists so a solid 2 feet of working room) but the flooring we've picked out is 3/4 inch wood for the main living space and thicker carpet for the bedrooms, two choices that seem to rule out efficient floor heating.

We are planning to spray foam on deck roof as the forced air cooling system lives in there and the space is un-conditioned. Bringing the attic into the envelope seems like the right choice for cooling efficiency. That leaves us with ceilings open and new drywall going up and hte attic space conditioned and walls being reinsulated when they get drywalled. Seems to me like a good fit for radiant ceilings...

Anyone have experience with radiant hot water ceilings and care to chime in or point me to some documentation? My initial look at things ended with me thinking we'd use oxygen barrier pex and set it up similarly to a floor but I'm seeing it'll need to be a bit more dense and run a little hotter as the estimated BTU/H output of ceilings is lower?

Any input is welcome, I appreciate the time.

Zman · February 2021

I have done several radian walls and will be begin working on a ceiling design next month.
I think it is a great option and in most homes can run at low temps similar to radiant floors.
Here is what the master has to say:
https://www.pmmag.com/articles/96488-radiant-ceilings-are-a-great-option-in-many-systems

hot_rod · February 2021

I retro fitted some radiant ceiling in my home. It is a close second to radiant floors, comfort wise
Walls are another option, or a blend of wall and ceilings

Floors in bathing areas if at all possible

iced98lx · February 2021

Zman said:
I have done several radian walls and will be begin working on a ceiling design next month.
I think it is a great option and in most homes can run at low temps similar to radiant floors.
Here is what the master has to say:
https://www.pmmag.com/articles/96488-radiant-ceilings-are-a-great-option-in-many-systems

That article is what sparked my thoughts. I keep going back to it as proof this isn't a terrible idea.

hot_rod said:
I retro fitted some radiant ceiling in my home. It is a close second to radiant floors, comfort wise
Walls are another option, or a blend of wall and ceilings

Floors in bathing areas if at all possible

What puts it below floors in comfort in your opinion? One of the rooms we'd be doing is the dinning room and I fear cold feet during dinner for example.

All bathrooms will be tiled and will 100% be heated in floor. I'm also planning to heat the tile walls of a larger walk in shower in the master, probably resistive so it can be manually bumped on for shower times.

Did you use a panel system on your install Bob? I don't really want to give up any ceiling height by putting panels below the joists, I was hoping to just install between the joists and drywall directly to the joists, perhaps I'm going to limit contact and thus thermal transfer?

unclejohn · February 2021

I worked on a house in DC that had rad. heat in cealing. Was a large home near the Cathedral. Had to bleed air up in the attic and that system keep the house nice and warm. Figured I had and air problem since the boiler was hot and pumps running but house cold. Went upstairs and guess what no radiators. Saw a cealing hatch in kitchen went up and found three auto bleeders valved off open up and all was fine.

hot_rod · February 2021

iced98lx said:

Zman said:
I have done several radian walls and will be begin working on a ceiling design next month.
I think it is a great option and in most homes can run at low temps similar to radiant floors.
Here is what the master has to say:
https://www.pmmag.com/articles/96488-radiant-ceilings-are-a-great-option-in-many-systems
That article is what sparked my thoughts. I keep going back to it as proof this isn't a terrible idea.
hot_rod said:
I retro fitted some radiant ceiling in my home. It is a close second to radiant floors, comfort wise
Walls are another option, or a blend of wall and ceilings

Floors in bathing areas if at all possible
What puts it below floors in comfort in your opinion? One of the rooms we'd be doing is the dinning room and I fear cold feet during dinner for example.

All bathrooms will be tiled and will 100% be heated in floor. I'm also planning to heat the tile walls of a larger walk in shower in the master, probably resistive so it can be manually bumped on for shower times.

Did you use a panel system on your install Bob? I don't really want to give up any ceiling height by putting panels below the joists, I was hoping to just install between the joists and drywall directly to the joists, perhaps I'm going to limit contact and thus thermal transfer?

Radiant energy travels in line of site, so I noticed at the dining table, feet under under coffee tables you did not get the true radiant experience, certainly it still covered the heat load, just not a 100% comfort system in my opinion, having lived with radiant floors in all our previous homes. It may not bother others.

Radiant floors, even under furniture will still perform. The exception being under cabinets, beds with ruffles to the floor, etc. There is a convection component to radiant panels.

You get a slightly better output from walls, often just the lower portion of the wall is adequate. The ceiling radiant does experience some stratification so the output is reduced when the ambient at the ceiling is higher than the rest of the room for example.

If you can get it above and in contact with the ceiling sheetrock, that would be my first choice.

Mine was a retro-fit, proof of concept, installed when my wife was out of town. Being exposed, it was not a crowd pleaser at my home

iced98lx · February 2021

Thanks Bob, that looks much like how I prototype things, my wife is similarly not impressed typically but if I'm going to do something multiple times the first time is going to involve the least amount of work possible!

I'm planning to augment my ceiling heat with toe-kick heat in a few places (the great room for instance has a very large island/bar separating the kitchen and living room, there is a fake fireplace in the dinning room we could use as a heat emitter etc) to try to up the comfort level in some of those areas and have some "reserve" BTU/H available for design days, doors being left open with the dogs etc. My current plan is to have an easy way to keep them off until needed to avoid the noise and air movement.

We also may upgrade the current forced air which is currently AC only to either be ducted mini splits or include a heat pump when we are to that point, which would also provide some options for shoulder seasons etc. This house is a very large project compared to our 900sq/ft fixer upper we're coming from.

TAG · February 2021

HR -- I like the industrial look.

I may try that some place ... may look cool with copper pipe and polish the plates .... brass screws. I think I will !

BirchwoodBill · February 2021

I have warmboard with With carpet and wood floors, it was a retrofit on 1986 construction. No problems with heat transfer. Our system is micro zoned using DHW tank with heat exchanger. 1 inch wood floors are warm running water between 83f and 103f on ODTR. Be sure to insulate the rim joists.

iced98lx · February 2021

BirchwoodBill said:
I have warmboard with With carpet and wood floors, it was a retrofit on 1986 construction. No problems with heat transfer. Our system is micro zoned using DHW tank with heat exchanger. 1 inch wood floors are warm running water between 83f and 103f on ODTR. Be sure to insulate the rim joists.

Thanks for the feedback Bill, what climate zone are you in out of curiosity? We're in Zone 6 here and just experienced what can only be described as a "Design testing week" of below zero temperatures and new record all time lows.

Steve_Wheels · February 2021

I LOVED my radiant ceiling. I had it in my master bedroom because I wanted "moon bounce" carpet and padding which was way to much of an insulator for radiant floor. I designed the ceiling to run at very low temperature (more plates, more tubing) so i would not get HOT while sleeping. BEST system I have ever had! Designed correctly, designed to what your expectations are for comfort, Radiant Ceiling is excellent!!! Please note: without proper precautions radiant ceiling is NOT advised to be used over concrete slabs.

Alan (California Radiant) Forbes · February 2021

What if you want to put a mirror on the bedroom ceiling? It's just a simple question.

iced98lx · February 2021

Alan (California Radiant) Forbes said:
What if you want to put a mirror on the bedroom ceiling? It's just a simple question.

At that point, once the divorce is finalized I probably won't own the house to worry about it, tbh.

jamplumb · February 2021

So Bob, Are you leaving your ceiling that way? This looks like the retro I would like to do but with a finished cover.

JohnGellatly · February 2021

Have thoroughly checked out Messana radiant panels, Google that idea. I love that the engineering data is available to tell you if it'll work in your space with heat load calculations done. Oh, and if you are redoing your walls anyway, take a look at cntradematt.com and check out their building insulatin Aerogel. With a 3/4" thickness you can get R60 walls, pretty sweet idea.

Sol_Brother · February 2021

To those who have installed hydronic radiant ceilings without using pre-made products like Messana panels, how did you achieve good thermal contact from the pipe/transfer plates to the drywall (or other finish ceiling)?
And to Steve Wheels, what is the issue with radiant ceiling above concrete floors? Do you mean that only if the concrete is uninsulated?

Mosherd1 · February 2021

@Sol_Brother I first ripped 3/4” plywood into strips and fastened perpendicular to the bottom of the framing. Pneumatic stapled my heat transfer plates up, then slid another 3/4” strip on the other side of the transfer plate and screwed it up to the bottom of the framing Then used 100% silicone caulk in the transfer plate as I put the pex tubing in the groove. Had to use some foil tape to hold pex up in certain spots until the drywall was installed, which sandwiched the aluminum plates tight to the back if the drywall, then blew in cellulose over everything from the attic side. The area over the kitchen with a vaulted ceiling had all the insulation work done first.

Sol_Brother · February 2021

Mosherd1, that is some very impressive work. Thanks for posting the photos.

iced98lx · February 2021

Thank you all for hte input and photos especially @Mosherd1 that is very helpful!

OaklandNS · July 17

https://forum.heatinghelp.com/discussion/comment/1646811#Comment_1646811

How is the system performing? Are you happy with it?

Hot Water Radiant Ceiling?

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