radiant heating ?

[PAGUY]

Anybody know anything about radiant heat that is an electrical pad in the ceiling? My sister recently bought a house built in 1973 and my understanding is that this is a pad that supposedly heats from above. Now I always have been under the opinion that heat rises so how can this be an efficient way to heat a bi-level home? She is having the ceilings repainted and the walls due to previous owners being heavy smokers and the resulting yellow tint to everything in the house. Her painter said he can just paint over with one or two coats and there should be no problems with the stained ceilings and walls. Any thoughts about this.

 

[davedj1]

We built condos in the eighties with radiant electric in the ceilings. They were sheetrock panels that fit in between the floor joists. I never liked it as I am tall and I could feel it on my head. We built quite a few of them and it seemed to work fine. I think part of the theory is that if your head is warm your body will be warm. I suppose that once the building is up to temp and insulated properly that you would hardly notice it. I think painting over it will be fine.
Of course you would have rely on the painter to use the proper sealer to cover the smoke.

 

[KubotainNH]

I lived in an apartment with this type of heat for 2 winters. Absolutely hated it. We were on the 1st floor over an unheated basement. Our feet were always cold but our heads were warm. I like it the other way around, radiant in the floor is great. The folks who lived on the 2nd floor probably liked our heat on their feet though. Sitting at the kitchen table was brutal because the heat does not get underneath it. The electrical bills were staggering. I think we had one month over $350 in a small 2 bedroom apartment almost 20 years ago. I can't imagine what that would cost now in an average sized house.

 

[Raspy]

That ceiling electric radiant was the cheapest way to add heat and it required no ducting or equipment. But it's terrible and a lot of it doesn't work anymore.

Don't ever make a hole in the ceiling to hang something, as you might cut the wire and finish it off.

I've never heard anyone who has used it, say they liked it.

If she ever remodels she might consider an electric system in the bathroom and kitchen floor where there is tile.

By the way, the painter may have to put a coat of KILZ on to seal the oil stains before any coat of regular paint will cover.

 

[PAGUY]

Thanks guys. Your comments are appreciated. I will pass them on to her.

 

[Jay4200]

Now I always have been under the opinion that heat rises so how can this be an efficient way to heat a bi-level home?

Common misconception. Heat does NOT rise, it radiates equally in all directions. Hot air does rise, but that is fundamentally irrelevant.

JayC

 

[Scotty Dive]

I have a house with it....I removed all of the thermostats and turned it off and installed forced hot air....I will tell you that - at my grandparents house, they had it and over the years (40+) a couple of their ceilings cracked due to the weight of the electric pad. Craziest thing I have ever seen.

 

[PAGUY]

Scotty Dive - They are installing two propane fireplaces that will have blowers to supplement the radiant heat.

Jay4200 - I always believed that heat rose so it is interesting to hear I was wrong like I imagine others also think that way.

 

[Raspy]

Heat doesn't rise.

Warm air, which is less dense than cold air, floats up in an atmosphere of cooler air, because it weighs less. Warm air rises the same as warm water rises in the ocean, or the same way helium balloons rise.

The heat from the sun gets to the Earth by radiation, it travels through the vacuum of space without convection or conduction. Radiant heat warms objects, like the Earth, people or walls, then air in the vicinity of the warm object warms up by conduction and rises because of gravity. The rising air is called convection. This transfers energy to cooler objects that are higher up. So it seems as though heat rises. Actually, warm air rises in the presence of gravity. But radiant heating is all about heating objects to begin with, and then the room gradually warms through convection and conduction.

This is why you can be in a cool room with radiant heating and feel perfectly comfortable. It's also why radiant is more efficient. Because you don't have to heat the entire space and all its massive walls, etc. in order to feel comfortable. That's why ceiling radiant is ridiculous, it only warms people's heads in a cool room. But leaves their feet, or anything out of the line-of-site of the ceiling unaffected.

At least with floor radiant you get warm feet first. Then the convection takes over, from the lowest point in the room, and the whole environment becomes comfortable. Much better than forced air heat, because a draft is not comfortable and a draft promotes evaporation. Evaporation is cooling. So forced air is also evaporative cooling that is overpowered by so much heat that it feels warm.

 

[BeezFun]

This is why you can be in a cool room with radiant heating and feel perfectly comfortable. It's also why radiant is more efficient. Because you don't have to heat the entire space and all its massive walls, etc. in order to feel comfortable. That's why ceiling radiant is ridiculous, it only warms people's heads in a cool room. But leaves their feet, or anything out of the line-of-site of the ceiling unaffected.

I agree with everything you said except this. Your body radiates heat to any surface that's colder than it is, so if you're in a house that has cold walls, you feel cold because your body is radiating heat to warm the cold walls. So while the ceiling is radiating heat to your body, your body is radiating heat to the cold walls and windows. So it is necessary even with radiant heat to keep the walls and windows at a temp as close to your body as possible to be comfortable. It may be a small temp difference, but radiation goes with the fourth power of temperature difference, so it can be a significant effect.