Radiant heat in walls

[markmudd]

I have non gasser boiler with forced air HX and 500 gal non pressurized storage at present that works very good. Looking for ways to use lower temp water to use less wood and I also have solar draindown system in place now and will be adding 120 sqft of collector area in near future that I hope will help with space heating, especially if I can use a lower water temp.

Anybody have any thoughts suggestions on installing radant tubing behind sheetrock on walls using aluminum heat emitter plates or if it is worth the trouble. I'd like to have radiant heat in floor but it does not appear to be practical.

My house is on a slab now, but raising the floor level would be a pain, my floor cover is good and the retrofit systems appear expensive.

I was thinking maybe just doing the lower 4' section on several walls, on at least one wall in each room but could do the full 8' wall if needed. Likelyhood of someone piercing pipe by hanging a picture etc would be increased but I could map pipes out on wall for future ref. I would not have to hire drywall work and that stuff is pretty cheap. Saw some of these projects on the build it solar site.

I already have pipe installed in my walls. Just have to decide which type of system to go with. Radiant in walls, baseboard etc.
Want to get away from forced air if possible except for AC

Thanks
Mark

 

[bigburner]

if you can get your hands an a Wirsbo Radiant floor design manual it has the math for walls and ceiling Mines 1st edition had it 18 + years, don't about newer text.

 

[DaBackBurner]

I don't know what your supply temps are for your water-air-hx but if your not able to use 130deg water and maintain temps you might want to check out the thread below before you consider other expenses first.
https://www.hearth.com/econtent/index.php/forums/viewthread/25090/
pybyr spent many hours and was willing to share with us all. (Thanks pybyr) He was going to put in other radiant systems but was quite happy then with his BIGDADDY water-air-hx. (I think he still is)

The other option you may want to consider is flat panel wall heaters, which are very popular in Europe and catching on here. These are excellent choices as well, just oversize them a bit and you can send fairly low water temps through them for great BTU output.

These options are a possible cheaper solution, but if you still have your mind made up and want to do radiant walls which can be a great way to heat as well, you might want to check out John Siegenthalers Modern Hydronic Heating 3rd edition.

Happy reading.

 

[tom in maine]

I have mostly radiant walls in my house.
They do work, but they require relatively hot water. They are comfortable, but I would also suggest radiant panels which can both
radiate and convect.
They would be less expensive and a lot quicker to install.

 

[markmudd]

Tom, how hot of water do you run in the walls? Did you make it the equivalent wall space for piping as you would have if in a floor or less due to higher temp water? Assume you use a mixing valve to control max temp? If max temp needed was 140, it would still be better than HX in efficiency, assuming it kept the house warm. In very cold weather, could still use HX.

 

[goosegunner]

Hopefully Heaterman will chime in about the radiant that he put behind the stone surrounding a fireplace. I would really like to hear about its performance and water temps needed.

gg

 

[tom in maine]

Tom, how hot of water do you run in the walls? Did you make it the equivalent wall space for piping as you would have if in a floor or less due to higher temp water? Assume you use a mixing valve to control max temp? If max temp needed was 140, it would still be better than HX in efficiency, assuming it kept the house warm. In very cold weather, could still use HX.

I just run whatever the tank temperature is. A radiant wall can output a lot more energy per btu because you do not have to stand on the wall as one would on a radiant floor.
Works fine for me.
I am not sure about your question about hx.

The tubing is space 8" OC and is in a panel that is foil faced.

 

[goosegunner]

Tom, how hot of water do you run in the walls? Did you make it the equivalent wall space for piping as you would have if in a floor or less due to higher temp water? Assume you use a mixing valve to control max temp? If max temp needed was 140, it would still be better than HX in efficiency, assuming it kept the house warm. In very cold weather, could still use HX.

I just run whatever the tank temperature is. A radiant wall can output a lot more energy per btu because you do not have to stand on the wall as one would on a radiant floor.
Works fine for me.
I am not sure about your question about hx.

The tubing is space 8" OC and is in a panel that is foil faced.

What is the covering over the tubing? drywall?

gg

 

[tom in maine]

It has 1/2" drywall over it. The surface was about enough for the heat load of the space.
The wall is about 120 sq.ft.
I sized it for the lowest usable heat output, so when the tank is hot, it runs only for short periods.

At the time, my wife thought a radiant floor would make her feet swell (?)
IN hindsight, I am considering installing the radiant floor.
She doesn't remember saying that a radiant floor would do that.

Pepperidge Fahm remembers!

 

[goosegunner]

It has 1/2" drywall over it. The surface was about enough for the heat load of the space.
The wall is about 120 sq.ft.
I sized it for the lowest usable heat output, so when the tank is hot, it runs only for short periods.

At the time, my wife thought a radiant floor would make her feet swell (?)
IN hindsight, I am considering installing the radiant floor.
She doesn't remember saying that a radiant floor would do that.

Pepperidge Fahm remembers!

Tom,


So do you feel the wall is a good way to go if infloor retrofit is impossible?

Could you run below 120 degree water and still get nice heat?

gg

 

[tom in maine]

I think 120F is a little marginal unless you have a lot of wall surface area.
As I mentioned earlier, I think radiant panels make a lot more sense and are really simple to
install and are inexpensive by comparison.

I happened to do a presentation today where a Runtal rep was also presenting.
They have very nice lines and have a variety of sizes and styles.
Biasi is another one that is locally available here in Maine.

 

[goosegunner]

I think 120F is a little marginal unless you have a lot of wall surface area.
As I mentioned earlier, I think radiant panels make a lot more sense and are really simple to
install and are inexpensive by comparison.

I happened to do a presentation today where a Runtal rep was also presenting.
They have very nice lines and have a variety of sizes and styles.
Biasi is another one that is locally available here in Maine.

Just trying to find some low temp options to extend storage below 135-140 range of my forced air exchanger. I have been looking at some old cast iron radiators also.

gg

 

[tom in maine]

Old cast iron radiators will work.
They are not as modern looking, but they will function the same. Sometimes modern looking is not right. I like the fancy old radiators.

I know a lot of people who get them sand blasted and painted by an auto shop.
Performance can be estimated. There are I-B-R guides online somewhere.

 

[goosegunner]

Old cast iron radiators will work.
They are not as modern looking, but they will function the same. Sometimes modern looking is not right. I like the fancy old radiators.

I know a lot of people who get them sand blasted and painted by an auto shop.
Performance can be estimated. There are I-B-R guides online somewhere.

They seem to be readily available here. A few things holding me back.

1.Money...the radiators are cheap but set up will cost quite a bit.

2. I am little concerned about introduction of rust into the system.


gg

 

[Willman]

From the recent Plumbing & Mechanical magazine and article on a new baseboard that works down to 110* Check it out.
Will

http://www.pmmag.com/Articles/Column/BNP_GUID_9-5-2006_A_10000000000001147251