Thread: ceiling/floor/wall hydronic systems

I'm writing my employer about some errors in their training materials and want to be sure I have my facts right.

Has anyone ever seen hydronic radiant panels on ceilings or walls in houses? I gather they're used mostly in commercial settings.

In-floor radiant is not normally used for cooling - am I right?

Steam is not used in in-floor radiant - true? (What are they thinking? - they're HYDRONIC systems! Apart from electric ones, of course. And hot air, which I've heard of but can't imagine being very effective.)

Is it true that open-loop geothermal is not used so much these days because of biological problems created by pond/lake water?

And finally, more of a question. When a boiler is used to supply radiant in-floor, is the temperature simply set lower than for radiators, or is it more common to have an indirect water heater as part of the system? Seems like the latter is much more efficient.

Thanks!

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Sorry not able for long response right now.

1) ".hydronic radiant panels on ceilings or walls in houses? ..."
Yes, call radiators. European design look more flat than typical older radiators.
I have not seen them on ceilings in a house.
Design is for cold air to rise off floor over radiator raising to ceiling and then cooling, creating a convection cycle.

2) "...In-floor radiant is not normally used for cooling ..."
Normally no. Will depend on floor materials for the idea to work. Cold air drops and it would be difficult to build cooled air in a room from the floor up.

3) "...Steam is not used in in-floor radiant ...'
Normally - no. Temp would be to high. Depending on floor material and design. Though it is possible.

4) "..open-loop geothermal..."
Still being installed. Typically it is a cost to payback issue is why many do not use it.

5) "...boiler is used to supply radiant in-floor ..."
Boiler can be used it is just a matter of temperature settings.
If there are radiators in addition to radiant floor there has to be mixing valves and more design since the floor is cooler than radiators would be.

1) I'm talking about systems that have special wall or ceiling panels with tubing installed within or behind them. They are being made, but my understanding is that they are used so far in commercial or public settings (schools, hospitals, offices, etc.), not in houses.

2) The main problem with trying to cool hydronically besides the inefficiency Garry mentioned is condensation due to cool tubing resulting in mildew problems in the flooring materials. That's for standard floor installations; some of the ceiling panels mentioned in 1) are designed to cool as well as heat.

4) I should have said, open loop as opposed to closed loop geothermal systems. Both are expensive to install (if anything, I would think closed loop more expensive).

From this site:
"Water quality is an important issue with open-loop systems. Mineral deposits can build up inside the heat exchanger, iron and other impurities can clog a return well, and organic matter from ponds and lakes can quickly damage a geothermal system. Water should be tested for acidity, mineral content and corrosiveness."

I hadn't thought of mineral buildup, but I was under the impression that these kind of problems are what favor closed loop systems vs. open loop systems these days.

5) Ah, I totally forgot about mixing valves! That would make sense.

Thanks, Garry!


A just-for-the-halibut photo: digging wells for closed-loop geothermal in SE MN. A cementitious slurry is pumped into the wells that soaks into the sides and keeps them from collapsing before the pipes are installed. The wells are 140-160 feet deep.

Kristi,

I'm not an inspector but a contractor.

To answer your 1st question (radiant in ceiling)...yes. Radiant panels or tubing in a ceiling are perfectly acceptable ways to install radiant. The floor is preferable but the ceiling and/or walls will work fine too-it's all about proper design.

Radiant heat does not care which direction it goes- if it did the sun would only work if it ws 'under' us. Radiant heat heats objects, not the air, and hot air is what rises. We just worked on a system (residential) that has all radiant tubing in ceiling and we are running hot water thru there at 100 to 130degF and customers are perfectly comfortable.

I don't know enough about radiant cooling to post, but it does exist, can be done, but not typically in residential settings.

Steam in radiant tubing? Never.

The indirect WH on the system is fine. Again, it's all about design and using the right controls to send the right temps to the right zones.

Hope this helps.

Jeff W

Radiant heat in ceilings is common in older homes in the Chicago area. I did an inspection of a Frank Lloyd Wright home recently to locate a malfunctioning zone valve. In the image with the valves, the center valve is cooler and malfunctioning.

Originally Posted by Linas Dapkus

Radiant heat in ceilings is common in older homes in the Chicago area. I did an inspection of a Frank Lloyd Wright home recently to locate a malfunctioning zone valve. In the image with the valves, the center valve is cooler and malfunctioning.

Awesone photos Linas, thanks for sharing those.

I concur with Mike's comments above. I also did a house in Park City where the radiant contractor placed radiant tubing behind a rock wall at the entry and in the great room. The space was probably 20 feet high and all glass on one exposure. The radiant effect was incredible!

I have worked on chilled beam radiant cooling systems but have never seen one in a residential project, with the exception of a high rise condo project. The cooling is not a problem for mold or condensation as long as the chilled water temperature is kept below the dew point.

Great thread.

Yes, great photos, Linas! I want one of those spiffy cameras.

Interesting info, too, everyone. I'd heard of hydronic radiant heating in walls and ceilings, but couldn't find any examples of it installed in a US home on the 'net, but knew I should check here before making any assumptions about it generally.

Wow, that would be so cool to inspect a Frank Lloyd Wright house!

I wonder if ceiling hydronic heat is found particularly in older homes, that means it wasn't very economical the way it used to be installed, and lost favor. There seems to be a lot of new technology out there; maybe we'll see it more often once more contractors learn to install it correctly.

I must have missed this page before, it's from the US gov't Energy Savers site:

"Most radiant cooling home applications in North America have been based on aluminum panels suspended from the ceiling, through which chilled water is circulated. To be effective, the panels must be maintained at a temperature very near the dew point within the house, and the house must be kept dehumidified. In humid climates, simply opening a door could allow enough humidity into the home to allow condensation to occur...
Homes built on concrete slabs are prime candidates for radiant heating systems, and radiant floor cooling takes advantage of the same principle using chilled water. ... Again, condensation is a concern, particularly if the floor is covered with heavy carpeting, and the effect is intensified by the tendency of cool air to collect near the floor in stratified layers. This limits the temperature to which the floor can be lowered."

It seems like in-floor radiant cooling would be a reasonable alternative in arid climates or in institutional settings, but doesn't seem very practical in humid climate houses.

"Radiant heat does not care which direction it goes- if it did the sun would only work if it ws 'under' us. Radiant heat heats objects, not the air, and hot air is what rises." (Mike Waldman)

If this were true, the air over tables, or anything blocking the radiant energy of a floor (or a radiator, for that matter) but not touching it, would be cold. Radiant heat actually relies on radiation, conduction, and convection. Besides, air is not a vacuum, it has weight and substance.

Gotta post something to clear the "no post message" and take care of a pet peeve at the same time.

Cold air sinks because it's more dense (heavier per unit volume) than warmer air.

Therefore, warm air rises only because it's being pushed in that direction by the colder air.

Originally Posted by Joseph Peake

Gotta post something to clear the "no post message" and take care of a pet peeve at the same time.

Cold air sinks because it's more dense (heavier per unit volume) than warmer air.

Therefore, warm air rises only because it's being pushed in that direction by the colder air.

The reverse could be said: warm air rises because it expands (lighter per unit of volume) from being heated, as such the warm air rises, as the warm air rises and displaces the unheated air (i.e., cold air) the unheated air sinks to replace the space left by the rising heated (warm) air.

Not being a scientist, I think it is a combination of the two actions which is actually correct, but if it was one or the other, then warm air rises ...

My thoughts:
The Romans brought radiant floor heating to an art form.
Ceiling radiant systems (mostly electric) are an abomination.
They're almost as bad as high wall FAU heating registers.
What were they thinking?
Floor hydraulic radiant heating is by far and away the very most efficient heating system ever developed.
Joe Eichler had it right, but lousy concrete slabs did him in.

This post had me reading and it seems the cold air being denser is heavier and effected by gravity just as the warm air is ,thus then displaces the warm air which otherwise would also be effected and sink but will not move through the denser cold air to do so.

Example: was a stone (cold air) being denser and displacing water.

Summary: is that the cold pushes the warm up through displacement.

Originally Posted by Bob Elliott

This post had me reading and it seems the cold air being denser is heavier and effected by gravity just as the warm air is ,thus then displaces the warm air which otherwise would also be effected and sink but will not move through the denser cold air to do so.

Example: was a stone (cold air) being denser and displacing water.

Summary: is that the cold pushes the warm up through displacement.

It is the warm air which does the action, here is why: 'cold' is the natural state, 'not-cold', i.e., 'warm' requires "heat" being added, therefore 'cold' air is in its natural state while 'warm' air is in the altered state and it is the natural state which stays steady and the altered state which migrates.

Thus ... ... it is 'warm' (heated) air which rises.

Originally Posted by Jerry Peck

It is the warm air which does the action, here is why: 'cold' is the natural state, 'not-cold', i.e., 'warm' requires "heat" being added, therefore 'cold' air is in its natural state while 'warm' air is in the altered state and it is the natural state which stays steady and the altered state which migrates.

Thus ... ... it is 'warm' (heated) air which rises.

If warm air rises then adding it to other warm air would make it all rise.
Cold air is still warmer than the natural state of sub zero.

Oops on phone make that absolute zero before I get chewed on. Lol

"Natural state"? What's that?

Hot air rises, cold air sinks. Cold air is denser than hot air (at a given pressure) because the molecules in hot air are moving faster and taking up more space. That is true whether there is colder or hotter air coming into a room; it has nothing to do with which is in an "unnatural" state...there is no such thing.

One of the problems people have with heated ceiling panels is their head gets hot and the rest stays cold.

Originally Posted by Kristi Silber

"Natural state"? What's that?

Hot air rises, cold air sinks. Cold air is denser than hot air (at a given pressure) because the molecules in hot air are moving faster and taking up more space. That is true whether there is colder or hotter air coming into a room; it has nothing to do with which is in an "unnatural" state...there is no such thing.

One of the problems people have with heated ceiling panels is their head gets hot and the rest stays cold.

Exactly meaning atoms not as densely packed making more air space.
When cold and hot mix the atoms get slower in the hot air as they collide making them heavier as they mix because of less movement needing less room and thus more densely packed.
Hope that made sense.

Ha! I knew that would comment would spark some friendly discussion.

Kristi's got the right idea - for purposes of this discussion, "natural state" could be equated with "ambient temperature"; it depends on the conditions that one is comparing and one's point of view.

Radiant Panels - The "warm head effect" of ceiling mounted radiant panels has more to do with radiation than stratification. It's much like facing the bright sun or facing a camp fire on a cold eve. If you energize the radiant panels in a cold room, your head (and any exposed sensitive skin) will feel warm very quickly and long before the overall air temp in the room rises.

Cold Air Sinks - The heat's off in a room. The room temp is 40degF. The boiler kicks on and delivers 180deg water to the baseboard. The air around the baseboard begins to warm (and becomes less dense as the heated molecules move further apart). The "lighter" warm air is displaced by the denser "heavier" cold air, thereby creating a convection current that (all factors being equal) moves up the wall.

The same logic applies air in a chimney, to weather patterns and, for example, ocean water. As the air (or water) cools, it sinks because it gets more dense.

Same w/submarines - as they take on ballast, they become more dense than the surrounding water and they and their DISTRIBUTION PANELS (in this one case SUB PANELS) sink only to the point of equilibrium with the surrounding water.

So, if we were to chill Congress, at some point the molecules would reduce in size and they would come together. Though they might be denser, but it is hard to believe they could be more dense than they already are.

If the head is warm while the rest is cold, that must mean the molecules in the head are less densely packed. Is this how air heads are created?

Hmmm, so should we warm or cool our heads of state? Do cooler heads prevail, or are they just more hardheaded?

I wonder how you made the leap from air heads to politicians?

Originally Posted by Darrel Hood

I wonder how you made the leap from air heads to politicians?

Was not a very large leap.

Just for fun with physics, cold is a relative term because everything above absolute zero is warm.

As for rise and fall if you place warm water below cold it will rise just as the cold will sink, both are accurate and relative to each other

I have hydronic radiant floor heat in gypcrete and it is the best heat I know of. Feels like a warm fire without the ash.

And I know all my animals agree!!!!

Originally Posted by Don Hester

Just for fun with physics, cold is a relative term because everything above absolute zero is warm.

As for rise and fall if you place warm water below cold it will rise just as the cold will sink, both are accurate and relative to each other

I have hydronic radiant floor heat in gypcrete and it is the best heat I know of. Feels like a warm fire without the ash.

And I know all my animals agree!!!!

The part you left out is that natural separation will not occur in space because the X factor is gravity.

Please think hard and tell me if I am wrong.

Put that same warm water in a glass below cold water in space and the same effect will not occur.They will simply mix through movement of the particles of atoms ,and this is of course assuming being done in a controlled environment since in space there is nothing but vacuum.

Now I will continue assuming that the warm will not separate in the same fashion since there is nothing to cause that effect of warm on one side and cold on the other.

If I am correct then it means the effect is a denser amount of atoms creates more weight (through gravity) and sinks below the less densely packed atoms(warmer air or water) due to gravitational pull.


This forces the warmer air/water up which only exists on terra furma since no temperature of anything repels from the earth otherwise you would have anti-gravity theory.

Hope someone understands what I mean by all this.

Bob, Well you would be right because you would have instant ice cubes ; )

The whole warm/cool air would only be relative in our environment on earth.

Temperature affects the density of a fluids (liquids and gases) creating the convection currents from denser and lighter fluid movement. And of course you need gravity to act on it.

Glad you understood my opinion.
Not trying to infer I'm an expert but am going by common sense as I know it.

This site is one that should be acknowledged as a good educational for us and needs to be looked at by all of us Inspectors. Building Science Information

Get the warm /cool interaction straight and we are ahead of most ,so lets learn and get this right.

Bob, Nor am I an expert but I did sleep at a Holiday Inn once ; )

I came out of bio-tech and my best friend is a scientist (I am not), but when you hang with those guys you can not help but get into all kinds of wild discussions.

Great link for Building Science. I frequent that site often.

My wife was giving it to me because I was in there yesterday reading an article while we talking.

Sorry for bring this old thread back to life but just for fun I wanted to share this picture of an in-wall radiant heating system during construction. The radiant effect was incredible. Walking into the entry area of the home the warmth of the rock was very noticeable and soothing.

Cool

Or should I say hot?.... Lol.

Originally Posted by Bob Elliott

Cool

Or should I say hot?.... Lol.

Say WARM.

Nice. I may do that if I ever get around to building a new house. My plumber told me about some bathrooms they did where they did radiant tubing on the shower walls and bench to add some warmth that worked really well.

Rod,

That is cool way of using radiant tubing. I would like to get a few pics from you on this if I could. I am going to do a blog on radiant systems and that example would be fun to use.

Anyone else have any cool radiant heat system pictures to share I would sure be glad to have them.

Originally Posted by Don Hester

Rod,

That is cool way of using radiant tubing. I would like to get a few pics from you on this if I could. I am going to do a blog on radiant systems and that example would be fun to use.

Anyone else have any cool radiant heat system pictures to share I would sure be glad to have them.

I can't take credit for the installation or the photo, just that I was there as it was happening. The real genius behind this system was these guys.: Radiant Heating Utah, Hydronic Heating Utah, Utah Solar Panels

And I am not financially affiliated with this group in any way, shape, or form. AND we are not related, but I'd be happy to call them brothers.