Radiant in Ceilings, instead of a Floor?

Mark_53

Need a little advise. New construction home on Maryland's eastern shore (Ocean City.) Not really cold here like up north but get some two week periods of slightly below freezing temps during winter months. Going with Warmboard on 1900 sq. foot first floor with 3 inch hardwood floors. Second floor is my question. Designed four bedrooms (1500 sq.ft.)on second floor, all with quality carpet and high desity thin foam. I can't afford more Warmboard on the second floor so it is either hydronic baseboard (use of a mixer from boiler) or radiant heat in the second floor 8 foot ceilings??????? My wife will kill me if she gets cold. Can anyone tell me if they are comfortable with radiant in ceilings (Good or Bad.) Will ceiling heat do the job? Thank you.

Weezbo

well a couple weeks back Hot Rod spun some in his living room while the lady was away a day and it looked like the way to cruise ..why not find that post and er ask him ...i have done a bit with the thick plates in an arctic entrance ! oh buddy it gets cold around here ) and when it was 55 below it was a tidy 72 ish good for the go ?

Gordy

I got it in my house Mark my system is 50 years old its method of construction differs from the modern method a bit. My ceilings are 8', I don't know if your remark about ceilings being 8' was considered a draw back. She won't be cold, and your head won't get hot.

Gordy

Mark Eatherton1

Absolutely!!

Radaint ceilings are better than radiant floors from an installation/operation stand point.

Pros:

1. You DON'T have to cover E-V-E-R-Y square foot of your home with tubing. Only put in whats necessary to counter the load (typically 4 foot band of exterior).

2. No limitations on furniture placement.

3. No limitations on floor finishes.

4. Generates SAME radiant comfort you'd expect from radiant floors, minus the warm floor.

5. Floors are warmer than they'd be with Baseboard radiation.

6. Can be set back at night due to low mass nature and quick pick up of radiant surface.

Cons:

1. Your feet are not in contact with a warm surface.

2. Ceilings greater than 12 foot tall don't have as much effect.

In retrofit considerations, you'll lose no more than the same amount of floor to ceiling height that you would with doing the floors with a gyp over pour.

I have a rather unique all copper radiant ceiling panel heater here in my office, and I LOVE IT!

I say GO FOR IT! You WON'T regret it.

ME

GMcD

Quibbling a bit

Mark- I'd question Pro #4 - radiant works on direct infrared heat exchange- if the are no heat gains or losses in the room, all the surface temperatures all reach an equilibrium point anyway, so a radiant ceiling will warm or cool other surfaces in the room to the point of equilibrium. Granted the floor temperature would not be as warm as if the heat source was in the floor, but in steady state conditions, the floor (and walls and furniture) would all be within a degree or two of the radiant emitter surface temperature.

Con #2 is also questionable- there are many instances of radiant ceiling panels at 30 feet above you still maintaining comfort conditions - there are some areas of Chicago's O'Hare International Airport where perimeter strips of radiant ceiling panels are maintaining a 28 foot high glass wall in acceptable conditions. OK, so they are running 200F heating water through it, but it still works. Radiant works as "distance squared" and "temperature to the fourth power" - you get a little distance from your radiant emitter, you raise the emitter temperature a little.

Tom_41

ceiling radiant

Working on design for an old adobe rooming house in Truth or Consequences (formerly Hot Springs until Ralph Edwards got them to change the name for the radio show)New Mexico. Client wants to put old t&g pine to 2x4 bottom chord of trusses for ceiling and put pex with rigid transfer plates above pine ceiling. Sort of a reverse staple up. Air space above pex and transfer plates and blown in insulation (32)
What factors need to be considered for heatloss calcs to compensate for ceiling install?
9' ceilings, crawl space W/ R 19, exterior walls foam board insulated/ plastered, new windows etc etc, air infiltration minimal, 100 year old building.
Especially like the 4 foot perimeter idea.
Any thoughts appreciated.
Tom

Gordy

Good technical data !

Thanks for sharing those facts Geoff. I'm always interested in the power of the ceiling radiant approach. My system does exhibit only 1 or 2 degrees temp difference ceiling to floor...... But I have floor radiant in the basement so I thought it may be skewing the numbers a bit.
Even if for that matter it did, Mark you having warmboard in the main floor you would have a sandwich of heat upstairs,if you decided to go with the ceiling radiant.
Gordy

Mark Eatherton1

Debate vs Quibble...

Geoff, I welcome your responses, and as you will see, I should have better prequalified my statements.

As you may have seen in previous posts, I design my customers systems as if I am going to have to foot the fuel bills, and I'm a tight wad in general...

You are obviously a respected guru in the field of radiant heating/cooling.

As for Pro 4, it has been my experience in the real world that not all surfaces emmulate the emmitter exactly. In a real ideal world, as you have noted, no loss, the surfaces would equalize becasue MoNature HATES imbalances in energy, pressure etc.. But in the real world, losses do occur. If they didn't, you and I and a whole lot of other people would be jobless... I went to a job yesterday where the zone valves' manual switch somehow was inadvertently put into the manual open position. In the words of the HO, "You could cook eggs on the floor..." Actually, the floor was at 87 degrees F, which based on my experience is NOT hot enough to cook eggs, but is hot enough to make human beans cook.

I checked the surrounding walls, ceilngs, floors etc to see if they had equalized, as one would expect in a situation whereby the heat source had been running wild for as long as this one had (2 months), and found the walls, and ceilings no where near the 87 degrees the floor was running. So much for equalization. They were elevated, but no where near 87 degrees F, and the majority of the surfaces were interior, with occupied space above and below. Still, it WAS uncomfortably warm within the space.

I guess what I'm trying to say it that radiant comfort is subjective. What's comfortable to me may not be as comfortable to an octegenarian in the same exposure, but radiant comfort IS more comfortable than convective comfort, hands down. Hence the statement "SAME radiant comfort you'd expect from radiant floors, minus the warm floor".

People who have experienced warm floors become easily addicted.

I've had customers call me in the Spring and Fall and ask my why their floors are not warm. I have to confirm that they are comfortable, which they generally reply to positively. I then have to explain to them that they can expect their floors to be neutral to the touch when they are not on. In some cases, they WANT warm floors REGARDLESS of the overall ambient conditions and potential wasted energy. Addicting...

In comes a programmable set back thermostat with a 2 degree set back:-)

As for Con #2, I stated, "don't have as MUCH effect." Key word MUCH.

Sure, with surface temperatures elevated, I can keep the occupants feeling the glow, but based on reasonable expectations from accepted practices (maximum recommended sheet rock surface temperatures), the further you get from the camp fire, the cooler you will feel...

If it weren't for the limitations of sheet rock mud, tape and paint, we could heat that puppy up to 200 degrees F and keep them nice and toasty...

Guess I should have spelled out my prequalifications and personal convictions prior to hitting the SEND button eh...:-)

Thanks for your valid and much appreciated input.

PS, I forgot to mention the PRO of being able to provide radiant ceiling cooling. Please expound for those who are unfamiliar with the potential of this burgeoning technology.

Again, Thanks!

ME

GMcD

Points noted

About the "equalization" of interior surface temps in a radiant environment. About that 87F floor and the surrounding surface temps, interesting. When I use my handheld surface temp meter, in "most" radiant spaces I've checked out there wasn't any great temp difference between emitter surface and surrounding non-controlled" surfaces in a "steady state condition" (no excessive room heat losses or gains, empty radiant ceiling spaces etc.). Usually the windows and any outside walls will show a cooler temp as they are continually transferring heat outside on a cold day, so their relative interior surface temps will be at a point where the heat transfer (radiant energy in vs energy transfer outside) is equalized.

Buildings are dynamic machines, it's all about learning "building physics".