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Bathroom heating options

Drewser Member Posts: 34
Hello again...

As I wade through the process of getting quotes for a boiler replaced, and deciding between 85% cast iron and 95% Triangle Tube, a thought occurred to me. We have a typical 'old house' bathroom...second floor, small, one exterior wall about 7ft x 8.5ft. Used to have a window but I removed it, patched the hole, and insulated that whole wall last year when we (finally) upgraded the tub to also being a shower.

I have calculated the heat loss using the Slant-Fin app to be just under 600 btu/hr. There was originally a radiator in there, but some former owner removed it and the 2 pipes are just capped off...they stick out about 12" from the small jut-out wall behind the tub. This is a 100 yr old FHW system (converted gravity).

I really don't have the floor space to put in a used cast iron rad. I do have access to one, but it is short, squat, and in bad shape...it was removed from a friend's bathroom 200 miles away during HIS remodel (he added a towel warmer radiator in its place). And I just found out this morning that he has had it sitting out in front of his garage, uncovered and ports uncapped, since last fall. So whatever water may be left in it froze during the winter (regularly gets to -20f). In other words, I'm not counting on that one.

I'd love to add a towel warmer unit, but boy oh boy are they pricey.

When the boiler is replaced and the system is drained, I intend to remove the caps and install ball valves with nipples and caps on them to easier facilitate whatever I decide to put in later.

My question is this: We are fans of the 'industrial' look, and were wondering if we could build our own towel bar radiator out of threaded pipe purchased locally, controlled by a valve to fine tune the heat output. So I have a few questions:

1) What pipe to use? Black iron, galvanized steel....I'd rather avoid copper.

2) Valve for fine tuning? Ball valve, gate valve, etc?

3) Any idea what iron pipe puts out (btu's per foot approximately) at, say, 160* water? I know there are a lot of variables there but a rough guess would be awesome.

The rest of the system is all threaded pipe and cast iron radiators. There is only one zone, all or nothing...we have an electric heater built into the exhaust fan/light, but we hate it. I'd like to use the heating system as long as the pipes are already there...the room never gets really cold, but at -25f outside it could certainly be warmer.

I appreciate any opinions, thoughts, ideas, etc that anyone has.

I'm including my rough home made system schematic from a previous post...

Thanks everyone!



  • STEVEusaPA
    STEVEusaPA Member Posts: 5,689
    edited July 2014
    If you do it...

    Use a globe valve to force water thru the home made towel warmer, but to do that you're going to have to get into the piping in the basement, Without looking at the piping, and 12 inches apart, there may not be enough pressure drop to get water thru the towel warmer

    Can you post some pics, of the near boiler piping and a close up of the supply & return take offs?
  • lza
    lza Member Posts: 40


    Its always great to brainstorm diy versions of things you see and love, but I'm afraid your homemade towel warmer made from threaded pipe may not be very pleasing to the eye after you are all done.  If you plan on using it for space heat as well, and match the design of manufactured towel warmers (ie a number of cross bars), with threaded pipe  you would end up needing to throw in unions between each set of crossbars.  There is also the issue of renting a threading machine, or finding a use hand threader on craigslist, otherwise finding a supply house to cut and thread each piece of pipe for the cross bar.  If you had a welding machine you could do socket weld fittings, which would be fast and easy.  Otherwise, you could try copper and paint.  If you do decide to build your own towel warmer, add a thermostatic radiator valve.  Neither ball valves or gate valves are designed for throttling (because of "wire draw").  And don't forget to throw in an air vent!

    If you don't want to spend the money on a new towel warmer, I would try to find a small used radiator on craigslist or if you live near a larger city, a salvage store.  That is what I used to dry my laundry on in the past!  You may be able to find a wall-hung one, which is more ideal for a small bathroom.
  • SWEI
    SWEI Member Posts: 7,356
    As long as you are OK with white enamel

    the Myson COS85/86 are not all that pricey.
  • hot_rod
    hot_rod Member Posts: 16,300
    DIY towel bar

    I built this super-sized one several years ago. Square and round steel tubing, a holesaw and cordless drill. I had a professional welder do the MIG welding. Powder coated white by a neighbor with that equipment.

    Easier still is copper tube and tees. If you use 95/5 you can powder coat copper also. I have a powder coated, copper coat rack that has been outside for 8 years or more.

    They need to watch the oven temperature carefully the powder melts real close to the solder melting temperature :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Drewser
    Drewser Member Posts: 34
    SWEI and Hot Rod...

    SWEI - I'll take a look at the Myson unit right away...thanks for the direction!

    Hot Rod - That is gorgeous. As it so happens, if push comes to shove, I work with a very good welder/fabricator who would likely be able to weld me something up with little difficulty. I initially steered away from copper since I was worried it might not be able to take the weight of towels and the intermittent grab from a kid getting in or out of the shower. It's far enough away that it shouldn't be a problem, but with kids you never know. Do you recommend using Type L copper (IIRC that's the thicker of the two types) or does Type M seem okay?

    Thanks again for chiming in!

  • hot_rod
    hot_rod Member Posts: 16,300
    edited July 2014
    how large

    or a radiator do you want to build?

    I believe 24- 30 wide with type M would be fine. No towel I know of could bend that, nor a small child.

    The key would be solid mounting to the wall studs.

    You can also make a nice towel rad with these base branch manifolds from Watts radiant.

    The base branch model is 48" long and has 1/2 brass sockets to take 1/2" copper. either 3 or 4" on center.

    They use to make an all brass version, brass tube, brass sockets

    Cap two opposite legs, supply lower bottom, return from top, add a small hygroscopic vent at the top.

    Here is a section of an old one I have kicking around for example.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream