Hello,  Been reading posts on these forums for sometime now,  a great resource.  We are in preliminary planning stage for radiant heat system for our 1906 house.  We are currently (slowly, very slowly) adding a basement, and plan on adding hydronic radiant heat for the entire house.  Currently there is no central heating in the house, we heat with electric space heaters and a gas fireplace.  It's a 2 story house, currently 1750 sf of conditioned space, which will increase to 2750 after basement and small addition is added.  I am leaning towards radiant ceiling for all 3 levels (including basement).  As far as I can determine from previous posts here, and other info, the only downside to radiant ceilings is not having warm floors, and your head being warmer than your feet.  Upside for radiant ceiling is no worries about blocking heat transfer with area rugs and furniture, no worries about requireing higher water temps for staple up under wood floors, which we would have to do. Also that metal heat exchange plates wouldn't be needed for the ceiling? Am I missing something?  Is there a better reason to go with radiant floors over ceilings?  Any one out there with radiant ceiling systems, including basements?  Positive or negative  experiences with radiant ceilings? 
Thanks for your help

radiant floors are more noticeably warm in *most* cases. In very low load conditions, that may not be true.

properly designed a radiant ceiling should result in excellent comfort at low temps. Not as low as the highest performing floors, but lower than most less performing methods.

ceiling requires plates: still, it is cheaper than any radiant floor method, typically, except tubing in a slab that has to be poured anyway.

May I suggest that you look at hanging Redwell Radiant heating units rather than radiant ceilings or floors. Cheaper to operate than natural gas.

www.redwell.ca

Another product, depending on what you pay per kilowatt hour, is Zmesh low voltage radiant. It can be installed directly on top of the subfloor, under any type of flooring you would like to use. The heat is even throughout and can be designed as primary as well, depending on heat loss.

In the end, it can be competitive with hydronics given that you don't have to "construct" the house to make it fit. The system are much easier to design and will have no maintenance costs.

Making a blanket statement that electric units are "cheaper to operate than natural gas" is, in short, a wildly optimistic marketing claim, redwell.

Electric CAN BE cheaper to operate than natural gas. It USUALLY is not.

That said, pretty cool product, I"m sure it has some great applications.

Thanks for the quick responses. I'm not interested in electric radiant heat, the idea is to include (probaly add at later date) solar hot water collectors for heating. I'm banking that solar hot water will become more price competitive as other fuel costs increase. We currently are using wall mounted electric ceramic radiant panels, and while they heat nicely and we are happy with them, I wouldn't say they save much energy. Very useful to quickly and cheaply add heating capacity to a freezing house, though. We especially like the fact that the surface temperatures won't sear babeys fingers, unlike the baseboard electric heaters we don't use.

Some further questions for the other responses:

My first post wasn't very clear, I actually was thinking that the ceiling radiant would require lower temp than staple up under the subfloor. We have over an inch of existing subfloor and wood flooring to deal with, plus area rugs. I understand that decreasing heat intensity is not linear with distance from heat source, but thought that since we are dealing with a radiant heat source basically the size of the room, the drop off would not be that problematic. Is there a formula available to calculate the required source temp for ceilings? I want low temp, because I want to be able to add solar hot water heat.

Why does the ceiling require plates? There is no worry about temp stripeing, and if you insulate adequately above, won't the whole ceiling eventually reach an equilibrium temp? I was thinking that plates would decrease warmup response time, by pulling heat out of the line faster, but didn't think response time was that important.

What do you think about using ceiling radiant for heating the basement? It seems like heating the slab is the favorite method, but I would like to be able to turn heat up and down in the basement as needed, Large concrete mass = slow response time. The plan is for the basement to be more auxillary living area (guest room, shop, storage) so it would not need to be heated continually same temp as rest of house. Zone temp changes on nightly or even weekly schedule (not hourly, I know that is to much to ask...). The basement will be well insulated, ICF walls, and 4 inches of slab insulation.

Sorry for all the questions, just want to understand this fully before we start.

plates are required to conduct heat to the drywall. otherwise you have a tiny amount of conduction and the rest is simply trying to heat up a cavity to eventually bleed heat downwards.

remember heat transfer is in BTUs/hr.. there is a time component. how fast you transfer heat matters, because it's being lost at a given rate, it needs to be replaced at that rate. It's not good enough to say "eventually" it will even out. sure; it will. probably at a room temperature you're not very happy with though ;)

ceiling radiant can require warmer or cooler water than a floor system. depends on the amount of floor you cover; the amount of ceiling; the floor coverings you are dealing with. you can't run hotter than 120 with drywall though so generally it works ok with solar. at the lowest end of the scale though I have noticed it seems to drop off faster than floor does (say, sub-100 degrees). so a high performance floor will outperform in many cases. that doesn't mean ceiling is bad, however.

If you attempt any fast temp changes in a high mass basement, comfort is not your primary concern. Perhaps unless you use a thick carpet on the floor. I say this because until the floor heats up, it will lower the Mean Radiant Temperature (MRT) of the space and draw heat from your body, making you feel cooler. If you use it nightly, pipe the slab and keep it heated. If you only use it on weekends, pipe the slab and use a 7 day programmable thermostat. with ICF walls and 4 inches of slab insulation in a buried basement, the ten degree room temp difference we might be talking about here won't cost you much.

ceiling would work; it just, like any other form of heat, would have to fight your cooled slab to make you comfortable if you're leaving the slab cold.

OK thanks, plates would  make sense for the ceiling then.  It's a plaster ceiling, so uneven surface would slow heat transfer even more. 

I was worried about the slab being a heat sink.  It will be covered, if we have the money.  I don't like concrete floors, would like linoleum or cork, something easier on my feet... Maybe I'll do both slab and ceiling, turn down thermostat for room, but keep slab heated.  Cost will determine that though.  
Thanks for your advice, I'm sure I'll have more questions in the future...

oh, it's plaster? wow. not many people doing that these days.

in the old days they just did pipes right in the plaster. I've never worked with such a ceiling so I don't know the exact method used, but if the plaster were thick enough, I could see an arguement for dropping plates there... but doing tighter tubing on centers.

Dayton, I have the utmost respect for all the radiant guys posting here. I've also been involved with radiant electric heat for 20 plus years from the ceiling but not radiant hot water. I used Radex a form of electric drywall heat 20 plus years ago. Those customers love it yet today. We just put it in about 1200 ft of our own showroom and love it along with many customers that have purchased it before.

I post from home and only follow the ICF side of this site bi-daily so I may miss a reply here. Send me a personal EM and I will help in any way.

Dave

Installing copper tubing in hand troweled ceilings - usually 3/8" soft - was a common practice in days gone by. The installer was careful not to operate his panels above 130F to avoid breaking down the bonding.

Depending on the cost of your fuel source, I would install radiant floor where I could and would look at wall and steel radiators also.

Where are you located? Do you need air conditioning? If so, ceiling radiant using hydronic can also be used for cooling. Not done much in the US but quite common in Europe. Can be tricky to design to make sure you don't run so cool you have condensation problems. But, it can be done, and has been done. I was going to do it until I scrapped my plans for geosource and radiant and decided to go with a Daikin heat pump system.

Radiant cooling in a 1906 home?

I didn't see where your home is located, but an owner built Icf home in Thompson Ct. built in 2001 had radiant placed in basement slab and in first and second floors, also the garage floor, 2700+ living space, he has never had to turn on the radiant heat for the basement because the ICF maintains the temperature comfortably, so build an ICF basement and put radiant ceilings in above grade floors.

that's a dangerous suggestion tony

I know people with uninsulated basements that are 80 degrees because their 1st floor radiant was not insulated properly. that doesn't mean that people in uninsulated basements don't need heat, and it doesn't mean that it's generally acceptable to use heat gain from above as a method of heating a basement.

If you friend attempted to do what happened in his house on purpose, he'd be lucky if it worked to his satisfaction. and if it didn't, he'd be in for a potentially much more expensive retrofit than some pipe in some concrete.