Walls and ceiling can make excellent radiant panels___ Do you agree?

[Mushroom Man]

According to the Manual of Hydronic Heating ...

Although the majority of hydronic radiant heating systems are installed in floors, the walls and ceiling of a room
can also make excellent radiant panels. This is possible because radiant energy travels equally well in any
direction. Just as visible light travels downward and sideways from a ceiling fixture to illuminate the surfaces
below, infrared light (e.g. radiant heat) will travel to warm the objects in the room below.<<

I hope this is correct because it would greatly simplify my barn renovations.

Has anyone here used radiant in the walls or ceilings? Do you agree that it works as well as floor heating?

 

[Gooserider]

There was an article I read that sort of agreed but had a couple of cautions to consider...

1. They suggested not running tubes above 4' in a wall - reason being that people tend to want to hang pictures, install shelves, etc. on the walls, and often use nails - aka "tube finders" to do it...

2. Ceilings above 12-14' tend to make poor panels, because even though radiant does travel in all directions, it follows the inverse square law like all radiating sources (power at a point will drop as one over the square of the distance, or double the distance get one fourth the intensity) and a high ceiling will be to far from the people and other things in the space to work well as a panel.

No personal experience, but it makes sense to me...

Gooserider

 

[DaveBP]

Although the majority of hydronic radiant heating systems are installed in floors, the walls and ceiling of a room
can also make excellent radiant panels.

They do make excellent radiant panels.

Do you agree that it works as well as floor heating?

That doesn't mean they work as well as floors. Yes, they radiate as well but the radiant floor also warms the air that it is in contact with. That warm air rises and makes the room temp "feel" different than a ceiling panel. And when you have heated floors you tend to run around in stocking feet because it feels so good. The amount of radiant area needed for ceilings and walls might be different than floor because of the way we perceive the heat.

Have you talked to a radiant designer to see how much they might charge you to design your system that you could then build yourself? Compared to the total cost of a radiant system it might be pretty small money to get it right the first time.

 

[tom in maine]

If you want to get away from radiant floors, consider radiant panel radiators. They can utilize lower temperature water than radiant walls or ceilings and will cost less.
I have radiant walls in several rooms and would install the panels in a heartbeat next time, since they are simpler and a small package can put out a lot of heat.
And they can be controlled with a passive onboard thermostat.
And they cost a fair bit less.
We installed a whole house (6 panels) in about 2 hours including tubing back to the boiler and purging the air.

 

[pybyr]

If you want to get away from radiant floors, consider radiant panel radiators. They can utilize lower temperature water than radiant walls or ceilings and will cost less.
I have radiant walls in several rooms and would install the panels in a heartbeat next time, since they are simpler and a small package can put out a lot of heat.
And they can be controlled with a passive onboard thermostat.
And they cost a fair bit less.
We installed a whole house (6 panels) in about 2 hours including tubing back to the boiler and purging the air.

Some friends of mine once rented a house that was on a windy hill within spitting distance of the Canadian border, and that had those Euro-type panel radiators that Tom mentions, and they indeed seemed like the cat's meow.

One big thing that I noticed is that they responded quickly to calls for change in temperature (such as if a spare room was turned down in general, and then was turned up for a guest), which is something that "in-structure" radiant (floors, walls, etc.) is infamously slow at.

Radiant floor gives you the wondrous comfort of cozy feet, but if you're not going to have that, then might as well go with a simpler system like the panel radiators.

 

[pybyr]

wonder if they'd radiate better if painted black?

Maybe that's what all of the "Goth Fashion" types who dress in black are really up to-- trying to be more efficient heat receptors...

 

[DaveBP]

I'm with Tom on the radiant panel radiators for ease of installation. For renovation work where you don't have the walls down to studs and joists they would be much easier to put in.

They use a little higher temperature water than tubes in walls or ceiling I believe. I'm not so sure they are less money for BTU/dollar.

Look up Runtal or Myson, those are the two I remember looking over. I think PexSupply.com sells Runtal; quick way to check ballpark prices.

And beware! Different manufacturers rate their panels' BTU output at different temps.

The house I'm building will be all radiant floors but I'm putting in a strip of radiant panels along the bottom of the south-facing window walls to cut the cold air that settles down from them on a winter night. Haven't yet decided which.

 

[Como]

Radiators are principally convectors.

But there is a product for wall use, basicaly aluminum base board with 2 pipes built in. They have a greater radiator effect and do not take up wall space. I am coming to the conclusion that mix and match is the best solution, for example you may need just a heated towel rail in a bathroom, but it is all going to be down to indvidual circumstances.

 

[tom in maine]

Radiant panels are radiators and convectors. A lot of the higher output units are convection driven.
I think the baseboard mentioned is the Heating Edge, from Smith's Environmental Products.
www.smithenvironmental.com

They put out about 5-600 btus/lf.

Of course they still look like baseboards!

The panels use a lot less wall real estate.

 

[Nofossil]

The issue about radiant ceilings losing effectiveness with height is to some degree an infra-red herring. The inverse-square law holds for point sources. If you're twice as far away from a point source, you'll be exposed to 1/4 of the energy. That doesn't work for diffuse sources such as an entire ceiling. the heat that you feel is basically the average of the temperatures of all the surfaces that your skin is exposed to. If it's the whole ceiling, that's a high percentage of the area regardless of the distance to the ceiling. In a very small room, you will lose some effective output to the higher walls, but in general that's not very much of an issue.

 

[Fred61]

The house I'm building will be all radiant floors but I'm putting in a strip of radiant panels along the bottom of the south-facing window walls to cut the cold air that settles down from them on a winter night. Haven't yet decided which.

I may be wrong but I don't think the radiant area below the windows will replace movable window insulation. The cold dropping off the windowsill is simply reverse convection. The room air is washing up against the cold glass and dropping. By placing radiant tubes below the window, I would think you are just pumping that air back up past the cold glass and cooling it. I would personally add some sort of low conductive window cover whether I had or didn't have radiant below the window. It doesn't take much to stop or at least slow down the convection as long as the insulator is closed on either the top or bottom. If both top and bottom are open you are making it into an even better convector. Like the panel on the front of your baseboard convector.

 

[DaveBP]

Fred,
The radiant strip I described is nowhere near as good as insulated shutters or blinds for heat retention. We used to use foam panels on the window walls in the one-room cabin we currently live in. The difference is astounding.

However, I have given up trying to gracefully install and remove insulation over windows filled top to bottom with cactus and other succulents. The new house will undoubtedly be the same or worse so I'm going to plumb for the radiant baseboard below those windows. With 110F water supply it will only just break even as far as adding heat to the room. It's one of those compromises I've learned to make between my ideals and my own basically lazy nature. These radiant panels will be something to add later if I find I need it. Maybe i won't find it necessary. I often find procrastination a useful design technique for reaching optimum balance between what's most efficient and what suits my lifestyle.

an infra-red herring

God, I do love a bad pun.

 

[Mushroom Man]

It seems as though the idea of using radiant heat from the wall, is deemed to be viable; especially when it is easier than the alternatives in my Mush Rooms.

The decision on whether to use radiant panels or staple up is a logical extension once the wall decision is made. I looked into the radiant panels and decided that the cost is more than I can rationalize in this application, unless I was able to find used units.

So, looking into staple up methods, I see metal heat shields or reflectors being used. I understand the principle.

Now the question arises of even cheaper alternatives (in my mind). At Home Depot, I saw some inexpensive foil sided (both sides) poly insulation (might be referred to a bubble wrap on this forum, I'm not sure). It is typically used for wrapping pipes. It sells in various widths and lengths.

I thought that if that foil wrap was used against the already well insulated plywood walls, in strips, and then the pex stapled (proper clips) up over it, an effective radiant reflector would be achieved. The first room is 41' long and I was planning to string the pex out 40' then loop back a foot lower, then loop back another foot lower etc. I was planning on 3/4"x10" boards in betwwen the loops that would support the inner sub-wall of Apenite or chipboard. Because mushrooms need a high humidity environment, we use a water sealer on that interior wall before painting. It works well to resist the moisture.

Would it work?

 

[tom in maine]

Most radiant panels I am familiar with are less expensive than a radiant wall would be and given the fact that they use convection as well as radiation, they put out
more heat with lower temperature water.

Here's another idea: install hot water baseboard fin tube and build your own enclosure. Baseboards work by convection and the taller the enclosure, the more heat output.
You mentioned Mushrooms or mush room--am not sure if you are talking about growing fungi or dealing with dogs.

If this is a utility space, a simple convector could be built with fintube and plywood. The only limitation to heat output is the height of the convector and the water temp.
This would work well with low temp water, which would greatly enhance the performance of baseboard fintube, which is usually limited.

I would build something at least a foot high.

And you can usually scrounge up fintube from a rehab where someone is installing radiant stuff.


Tom
www.americansolartechnics.com

 

[Como]

http://www.discreteheat.co.uk/downloads/technical/discreteheat.pdf

Page 4 has a diagram showing heat distribution between radiators and Alu Baseboard. UFH is actually better in distribution but a more complicatd install especially in a Refurb and taks a long time to heat up.

It is a UK site but they export and I was told they will be soon announcing a US Distributor - NJ I thing, certainly East Coast.

I have a high heat loss environment, but was shown how I could stack them, one on top of the other. Radiators will take up a lot of wall space, taking up the foors would be extremly costly. So I am thinking a combination of Radiators and Baseboard. Operate both of the same heat supply.Have yet to work out price comparison, usually Radiators would be cheapest, UFH most expensive, but US Prices for Radiators are relatively high.

 

[tom in maine]

I am EXTREMELY skeptical of any device that has aluminum as a water passage.
I have had too many corrosion nightmares any time aluminum has been in the loop.

These types of baseboards seem to show up every couple years and then disappear.
I would suggest extreme caution, at very least, when considering aluminum in a heating loop that has any other
metal in the same loop.
And be mentally prepared to deal with a problem within a year or two.

 

[Como]

In the UK Steel is normal for radiators, copper for piping. In Europe aluminium is more common than steel.

But pex seems to be replacing copper.

I do not know what manifods are made of, SS?. So with pex that would leave the heat exchanger, copper.

If you add radiators in then of course that would could add other metals, unless they were o a seperate circuit.

Certainly something I will check.

 

[tom in maine]

If we were talking about a PEX and aluminum heating system, aluminum might be okay.
But there is usually always some other more or less noble metal in the loop and then you are circulating water through it.
Galvanic reactions start to take place.

I have heard rumblings about problems with the aluminum radiant panels (like the steel ones we are talking about) having some serious issues.

Having to replace whole systems that had minor amounts of aluminum in them (at a large cost) and then watching the same thing repeat itself
several times over the years, I will take a pass.

There is one radiant baseboard I have seen that uses an aluminum fin with a snap fitted PEX tube. The thermal performance cannot be that great,
but the corrosion issue is gone.

If anyone wants to use a radiant baseboard, there is a significant cost associated with them and the btu output is quite limited. They rely on higher temp water to get anything appreciable out of them.

Would be a lot easier if the aliens would share those shiny suits they wear to keep warm! Wonder if it is foil faced bubble wrap?

Tom

Time for more coffee!

 

[DaveBP]

I am EXTREMELY skeptical of any device that has aluminum as a water passage.

Look at the automotive radiator industry. Even with the expensive special coolants aluminum radiators don't last very long. I've never heard of one being flushed out and reinstalled like the traditional copper radiators. They just throw them away after a relatively short life.

Then what happens when some well intentioned boiler guy puts some boiler protective chemical in the system? Ever seen how well aluminum holds up to alkali?

 

[BrownianHeatingTech]

I have to agree on the aluminum thing...

I won't use aluminum anywhere that gets wet in a heating system, whether radiators or aluminum-block boilers. Steel (never galvanized), stainless steel, copper/brass/bronze, and pex.

There are plenty of options that avoid the use of aluminum, or limit it to applications like heat transfer plates and fins, where it never interacts directly with the system water.

Joe

 

[Gooserider]

Aside from the material, is the basic concept sound? - I could see where it would be a useful thing to have the heater looking like trim wood rather than a more conspicuous baseboard... I also liked their concept of the snap in gaskets for the top edge finishing and floor edge, with the space for running low voltage wiring - nice touches.

Assuming it is a viable concept, do you know if there are people making an equivalent product in a more compatible metal (i.e. copper or steel)

Gooserider

 

[BrownianHeatingTech]

Aside from the material, is the basic concept sound? - I could see where it would be a useful thing to have the heater looking like trim wood rather than a more conspicuous baseboard... I also liked their concept of the snap in gaskets for the top edge finishing and floor edge, with the space for running low voltage wiring - nice touches.

The radiative surface area of baseboard molding is pretty small, so you have limited output potential, if you keep the surface temp low enough to be safe.

It could work for a super-insulated house, possibly, but for the majority of construction, you would need to have a larger area than just that, like the floor, ceiling, or a larger chunk of the wall than just the first few inches.

Joe

 

[Como]

From their web site:


ThermaSkirt ® is aluminium & does not use copper lined bores – isn’t that a problem?

Ask what the heat exchanger in your boiler is made from: Aluminium. Ask what the best radiators are made from: Aluminium. Ask what UFH allupex pipes are lined with: Aluminium. As a result if not having copper lining were a problem, every boiler and every aluminium radiator and every UFH system would have a problem. It’s a misnomer. The use of copper lined bores or pipes is a throwback to old technology when joints were soldered. The use of plastic push-fit has revolutionised plumbing, and ThermaSkirt ® is the only one that uses patented inert plastic push-fit fittings.
Back to Top
Wont copper bores last longer?

Hey? Aluminium has a greater corrosion resistance than copper (or steel) especially when there is no oxygen present such as in the central heating water. In fact, mixing copper & aluminium in close proximity may facilitate a cathodic (electrolytic battery type) reaction. Mix that up with brass and stainless steel fittings and moisture and you have a recipe for a real event!. Discrete Heat recommend a corrosion inhibitor suitable for alluminium radiators. Fernox F1 or similar in accordance with manufacturer guidleines will reduce chemical reactions with the alluminium and inhibit limescale depsosits.

As far as super insulation is concerned, not required. I have a relatively massive load, if I just use Radiators, still a possibility, it will use a lot of wall space.

 

[Gooserider]

From their web site:


ThermaSkirt ® is aluminium & does not use copper lined bores – isn’t that a problem?

Ask what the heat exchanger in your boiler is made from: Aluminium. Ask what the best radiators are made from: Aluminium. Ask what UFH allupex pipes are lined with: Aluminium. As a result if not having copper lining were a problem, every boiler and every aluminium radiator and every UFH system would have a problem. It’s a misnomer. The use of copper lined bores or pipes is a throwback to old technology when joints were soldered. The use of plastic push-fit has revolutionised plumbing, and ThermaSkirt ® is the only one that uses patented inert plastic push-fit fittings.
Back to Top
Wont copper bores last longer?

Hey? Aluminium has a greater corrosion resistance than copper (or steel) especially when there is no oxygen present such as in the central heating water. In fact, mixing copper & aluminium in close proximity may facilitate a cathodic (electrolytic battery type) reaction. Mix that up with brass and stainless steel fittings and moisture and you have a recipe for a real event!. Discrete Heat recommend a corrosion inhibitor suitable for alluminium radiators. Fernox F1 or similar in accordance with manufacturer guidleines will reduce chemical reactions with the alluminium and inhibit limescale depsosits.

As far as super insulation is concerned, not required. I have a relatively massive load, if I just use Radiators, still a possibility, it will use a lot of wall space.

As I understand it, Pex-Al-Pex tubing has an inner lining of Pex, so the water never touches the aluminum... Not sure what they are referring to by "UFH allupex pipes" Not sure about some of the Euro stuff, but seems like all the boilers I see folks talking about in the US are using steel or stainless heat exchangers. The circs we seem to use are cast iron or brass, ditto the valves and other fittings, pipes are steel or copper, I don't see any aluminum anywhere in these systems.

My recollection is that there were a LOT of problems in the early automotive days when they tried to use Al rads w/ cast iron engines, or copper/brass rads w/ aluminum block engines. However if an all aluminum system is used, they work pretty well. I used to do a bit with liquid cooled computers - same thing, if a system was built with a mix of copper/brass and aluminum, it was very likely to develop leakage problems - anodizing the aluminum helped slow it down, as did use of regularly replaced anti-corrosives, but it was still a case of "when" it leaked, not "if"... However all Al, or all Cu/Brass systems worked quite nicely.

I don't know, but I would think that an all Al based heating system might work alright, but I wouldn't want one where mixed metals were used.

Gooserider

 

[tom in maine]

If aluminum is present in all these aforementioned places and you feel it is not an issue, then go for it.

Aluminum in contact with anything that has copper in it will sacrifice and corrode. Period.
If it is in contact with steel or iron, the steel or iron will corrode and plug it up. Period.

If you do not believe that, that is fine.
Just be forewarned.
Anyone who has worked with this material can pretty much guarantee a future corrosion problem in a conventional plumbing system with aluminum
baseboards is as sure a thing as the air we breathe.

These baseboards have made at least three go rounds that I can recall. All those companies have taken these baseboards off the market.

Once bitten....