Recessed radiator -- options?

Orple

My bathroom is currently heated by a recessed radiator on a one-pipe steam system. Not recessed in any elegant fashion, mind you; literally, a normal radiator (10 section, 4 column, thin-tube), stuck in a sheet metal box (open to the bathroom) and stuffed in the wall. An external wall, ta boot.



I can't find much about recessed steam radiators, but they seem like a relatively inefficient way to heat a room. The only merit it has is that it saves room in an already cramped bathroom. I figure my options are as follows:



1. Keep it where it is; maybe try to insulate behind it better. Will save re-piping.



2. Build it into an interior wall instead. Also saves floor space, no loss to outside.



3. Install radiant heat instead, either off of the hot water heater or off the condensate line.



Note: installing it on the floor isn't an option. It's a tiny bathroom.



Any thoughts on what my best option is here?

nicholas bonham-carter

Bathroom options

I would get some foil-faced foam insulation, and line the recess in which the radiator lies.

Are you sure that radiator is getting steam at the same time as the rest of the rads?

A plate of butter placed on each of the radiators in your house should melt at the same rate (have toast ready).--NBC

Orple

Timing

It heats up at the same time as the other radiators. I'm pretty sure (as per my other posts) that my system has some serious issues at the moment, but surprisingly timing isn't one of them. Once the radiators finally start warming up, they almost all warm up at exactly the same time.



The primary reason for considering a significant change here is that the built-in box seems pretty inefficient, and it allows a noticeable heat loss when the radiator isn't on.



I take it you're suggesting that I might be able to significantly improve the insulation there and make it work?

nicholas bonham-carter

Insulation-insulation-insulation

Yes--NBC

Hap_Hazzard

That's exactly what I did.

I ripped out the old, deteriorating insulation, put in some 3/4" foil-backed insulation and a layer of sheetrock, then I plastered the whole thing. Now every morning there's a cat sleeping next to the radiator.



Since I was also re-tiling the bathroom floor, I put a piece of marble threshold under the radiator, pitched slightly towards the supply valve. The marble not only looks nice, but it allows the feet to slide without making a sound when the radiator gets hot. It's the quietest radiator in the house.

Orple

I like it

I like it, and think I'll go with it. Just one question: why the plaster on top of the sheetrock? Extra heat protection, extra insulation, both?

Orple

Oh, one other thing

I was thinking that it might be a good idea to frame it with a 45 degree angle on the top of the box to help the heat out, along with a panel in front that would seal it off except for 8" or so on the bottom and top, to help the air move through it rather than just sitting there. Any reason anyone knows why that would be a bad idea?

Mark N

Recessed Rad

I have a recessed rad in my bathroom. It is an ARCO Sunrad. These were built to be recessed. They are no longer made. Burnham makes a similar rad it is called a Radiant. They are still available new.

gerry gill

you would loss some

of the radiation ability of the radiator, but you would aid convection...i like Hap's way, and i would add, have the radiator sandblasted and powder coated and it will look better than brand new..now you would be proud to have it showing in the room. Put a front panel on that acts more like a picture frame..even perhaps have a new valve 'nickel'd at a plating shop and installed..

Hap_Hazzard

Appearance.

I just wanted it to look nice. I removed the radiator cover someone had made for it and just painted the radiator and left it bare. Since it's a small, thin-tube radiator it's easy to see the wall behind it.

Hap_Hazzard

Definitely

I didn't powder-coat mine, but I really wanted to. Instead I used a white Rust-Oleum High Heat paint. It looks pretty good and it didn't even smell bad the first time the heat came on. But powder coating is the way to go if you can swing it.

Orple

Painting vs powdercoating

I'm definitely planning on having the radiator redone; right now it has a lot of flaking paint and rust on it, so that'll need to be fixed. I got two quotes -- one from a sandblasting company, one from a company that focuses more on radiators. In the estimates that I got, both listed priming and painting, but not powder coating. I imagine they might do it, but it's probably going to be a bit steep for me. At present, I plan to have them sandblasted and then do what Haphazard did.



As to nickelcoating, it sure is tempting, but I'm likely to be happy with a shiny new brass one anyhow, as the current valve is covered in rust. On that note, I'm guessing I'm going to have to paint the supply pipe as well, though, because its also covered in rust from the bathroom humidity.



I think I will leave it open, though. Think it's still work putting in a 45 degree on the top of the box, or just leave it as it is?

Orple

No room....

So, I opened up the walls today, and found that, aside from a sheet metal shell, there was nothing separating the radiator from the outer wallboards of the house. I'm going to add a 1" layer of foil-faced insulation, and just have the radiator stick out of the wall by 1" rather than being flush. I should be able to minimize that as well if I put trim around it.



I'll be pulling up the old tile floor, too, so I may just go with the piece of marble yet!

Orple

Flamability

So, if I put extruded polystrene back there, I'll have to cover it with at least 1/2" of drywall as a fire barrier, which will bring me out to 1.5." So, I'm exploring my options.



1. I could just bite the bullet and come out 1.5" as planned. The radiator would, at that point, be only 1/2 recessed at that point, and may be a nuisance since it's right next to the toilet.



2. I could put in 1/2" and drywall, and be out only 1" but with less insulation.



3. I could put in a layer or two of reflectix insulation (dual-sided foil barrier with bubblewrap inbetween) with no drywall (since it's non-flammable) and still be basically flush. It would be R3.7



One other question: since I have a sheet-metal enclosure for the radiator (albeit, painted), is the reflective barrier on the insulation pointless?

Orple

Reflectix is out

At least for this application. For anyone interested, http://www.heatinghelp.com/forum-thread/68002/R-value was very helpful in figuring out why. I'm working on the assumption that the sheet-metal shell will already be enough of a radiant barrier. What I need is more conductive barrier.

Stuart Rogers

Novitherm reflectors

A couple of years ago, we put Novitherm reflectors behind all the rads on exterior walls of our 1925 apartment building. They make a huge difference. In my own suite, I had to turn the rad thermostats (Honeywell) down by one full number. The reflectors are only about 1/2-inch deep, made of a lightweight plastic with a highly reflective coating. (The depth is because they are formed with angled ridges to improve convection currents.) They are applied to the wall behind the rad using double-sided tape.  You say you're now looking for a convection barrier, but you might also look into Novitherm to improve radiant transfer. http://www.novitherm.com/



I found this thread because I'm planning to reno my bathroom and want to recess the rad (on an interior wall). Poking around on this site is always educational.



Good luck with your project!