Does anyone have any experience with electric radiant heat ceiling panels? I am converting my daylite basement into a small Mother-in-law apartment. Our gas furnace does not have the capacity to heat this additional space ( approx 430 sq feet). I know baseboard heaters are inexpensive to install but with so little floor space the ceiling option sounds much better. I have also read about some warm boards that can be installed under the sheetrock. Any comments or suggestions on heating option would be greatly appreciated.
P.S. I am located in Seattle
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I work in a small office building that has the panels in the ceiling. I'd really only consider them as they are used there -- as supplemental heat to "balance" the main heating system, so that you don't have one end of the room too warm and the other too cold.
Take a look at Step Warm Floor at http://warmfloor.com/
It is a very unique and efficient system that is very thin. It is also suitable for total heat. I considered it for my kitchen remodel but since my existing gas system has the capacity and gas prices are favorable I'm going with hydronic.
We did tons of electric radiant ceiling heat back in the 70's, not panels but the entire ceiling. Remember when nuclear power plants were new and promised unlimited, cheap electricity for all? That didn't work as planed, neither did the ceiling panels. Very expensive to run, hot head, cold feet, drafty. I would think about oil filled electric baseboard in your situation. Relatively inexpensive to purchase, simple installation, no annoying fans, some heat retention, quiet and clean, capable of maintaining different needed ranges of heat and comfort, practical.
Ceiling radiant is really the wrong location for radiant heating IMO. The floor is tough because your slab isn't insulated. Baseboard you don't like ... then maybe wall mounted fan forced radiant heaters ... Cadet or Kadet used to make such products and they were often used in the NW for energy efficient houses that had such small loads that it was an inexpensive option. The fan helps force convection for better distribution. This of course requires wall space that won't get covered (although the wall space is small). In the mild weather of Seattle, you may find this to be a reasonable option.
Why
is your opinion that the ceiling "wrong" for radiation?
I agree it is not very common, but curious on what is this opinion based.
Not really wrong, but in residential applications it isn't the best approach. It's low temp and it tends to focus a lot of heat at the ceiling level ... which simply tends to move upward through the floor above (since it isn't 'high temp') which tends to promote stratifying the air temp a little. It doesn't 'reflect' heat downward like high temp high bay type systems do. Radiant floors are nice because they warm the part of the building you are frequently in contact with ... the floor. It is also low temp, but it tends to promote more even heating throughout since it starts w/ the floor and moves upward. I consider this the bottom of the barrell for radiant heat. I'm not saying it doesn't have a place, just that for most applications it's probably not the technology of choice. But hey, if you can't do radiant floors and other options also are difficult, it can be a reasonable answer in an otherwise tough situation.
These systems technically are not radiant heating since true radiant heating is generally considered a much higher temperature.
I remember my doctor using radiant art in his exam rooms. Kind of nice for the application. Turn them on when you need it, otherwise let the space 'idle' with it off.
The reason I asked is that my professional experience as an HVAC design engineer is just the contrary. I have designed and placed into service several very effective and very comfortable systems that included radiant ceiling heat in one fashion or another.
I used radiant electric ceiling panels as a "personal supplement" that provided less than 10% of the heat in a given patient area. Just a little extra when they felt chilled (which I'm told happens frequently during dialysis, I do not know personally). Had good feedback for that application. I never used electric radiant ceiling panels in any other application. I did see them in a basement office as the sole source of heating. The office had so many problems due to humidity control and poor ventilation, the radiant heating wa the least of their issues.
The last school HVAC system I designed was in Lake Geneva, WI and I used a combination hydronic ceiling panel/slot difuser at the exterior wall/window of each classroom (in lieu of the standard outer skin radiation baseboard ) in conjunction with hot water reheat in a variable air volume system. One of the most comfortable systems ever.
I agree that a large portion of heat tranfered to a space through a low temperature infloor heating system is via conduction and convection. However, useful heat from above (not counting forced air designed with enough throw to reach the floor) is almost purley radiant.
It (electric radiant ceiling panels) would not be my first choice for the sole source of heating in any application.
I don't get to design many residential systems, however. Those go to the low bidder and they don't use designers.
Yeah ... patient rooms is probably a good application. Don't get me wrong. Almost every technology has a good application somewhere. Ceiling radiant, as you stated, almost purely radiant ... is correct. To get that, though it TENDS to be a little more inefficient (since a bunch of the heat moves upward, not downward).
Radiant floors keep the feet warm and then the heat begins to migrate upward for fairly even heat. It can feel warm even when the space temp is a bit cooler (i.e. I can now set the stat say 2-4 deg cooler for the same relative comfort level). The floor is the only part of a building that we routinely touch. A little warm is a LOT better than 60 deg.
I don't think I've ever seen a hydronic radiant ceiling. Mostly electric (which can be a bit expensive compared to gas heat).
I believe everything has a place somewhere, sometime. I think your patient room application of radiant heat sounds like a good application ... as a supplement for occasional patient discomfort.
Currently, I see more and more hydronic radiant ceiling panels used in commercial designs. Supplemental heat in bathrooms seems to be the most common application.
I regulary debate the plumbers over on The Wall about the relative merits and efficiency of radiant systems.
A little heat on bare feet goes a loooong way to the perceived comfort level.
Overhead radiant heat in a bathroom has the advantage of warming the seat.
And a good reason
to leave the seat UP!
Based on my experience, if you attempted to heat an area (vs simply "even off" the temp) with the ceiling panels, people sitting under them would feel like they were being baked from above. You get just a hint of that sensation when they're used to "even off", but it's not to the point of being unpleasant.
You tried to heat an area using overhead radiant panels? And then found it didn't work well?
I have very limited experience in using such heating methods an I am interested in the specifics of yours.
You tried to heat an area using overhead radiant panels? And then found it didn't work well?
No, I work in an area (reasonably well insulated modern brick building) with both overhead panels and conventional forced air heating. It works OK, but if the radiant panels were on any more (as would be necessary if they were the sole heating source) it would get pretty unpleasant.
Makes sense to me.
Electric Radiant Heat Panels
You might look at radiant cove heaters. I have used them and they seem to work well.
SRS
Radiant ceiling is excellent
radiant floors are generally superior, but radiant ceilings are excellent emitters. Like radiant floors though they have to be done right. They require insulation above them, and they require modulation capabilities.
The old electric radiant ceiling panels that "didn't work" or gave "hot head" were not modulating devices. They overheated the ceiling and made the "temperature asymmetry" of the space way too high... hot head and cold feet.
however modern systems do not have to do this. with electric systems this means you'd need to use a system that can sense ceiling temperature or that in some way responds to actual room temp. I don't know if that even exists, but that's what would need to be done.
hot water systems, of course, can use "outdoor temperature reset" or other methods to lower the water temps when higher temps are needed. all of these strategies would reduce the "temperature asymmetry" and improve comfort.
I have many clients who love their radiant ceiling systems and the one here in our shop is very comfortable too. But if you have cold feet (uninsulated slab floors) or poor radiant ceiling emitters it is a poor choice.
Radiant ceilings are really great and often cheaper than floor; it can be competitive with hot water baseboard in hot water systems, and it's certainly a trade up from that.