Towel Warmers -

Steve Ebels

Ours are always piped on a dedicated loop and installed with a TRV to limit bathroom temp and shutoff automatically in summer. It works great with the way all of our systems are piped. (constant circ with reset)

Glen

I have a customer --

that would like towel warmers in addition to the radiant. Any recommendations as to preferred products? And should this be piped as a wild loop or as part of the radiant piping/controls - low or high temp etc. Boiler is a vitodens. I do have a engineered design for this - and do have my own thoughts for the installation - but am curuious how other water wizards do it.

Cheers

Alan(CaliforniaRadiant)Forbes

Any way you want

It's just a question of how much your clients want to spend and how they are planning to use it.

Cheapest is to pipe it in series with the radiant loop for the bathroom (see photo), but it won't be as hot as a radiator and it will only warm up when there's a call for radiant, i.e. no separate control of the towel warmer.

A little more expensive way is to pipe it as a separate loop with it's own thermostat (low temperature) and the most expensive is separate loop (high temperature).

Best wishes,

Alan
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Steve Paul

towel warmers

I have always piped my towel warmers in series with the hot water to the tub or shower valve. It gets hot only when the shower or the tub is being used and is not dependent on the heating system. The domestic hot water is more than sufficient to heat the towels and when connected this way is an on demand system.

Dave H_2

Towel warmers on domestic

Just make sure that the unit being used is a non-ferrous towel warmer or eventually it will produce not only warm towels but wet ones also.

This is a great idea because the heating system is used only part of the year whereas showers are taken throughout the year!

Wayco Wayne

I am installing one

on a job right now. I have a constant circ. high temp manifold feeding several low profile baseboards by Hydronic Alternatives. This manifold will be on an outdoor re-set control. I just added a loop for the towel warmer and put a thermostatic radiator valve on the towel warmer. If you want to see some fancy Towel Racks look at a catolog for Hydronic Alternatives. Pricey but way cool and fancy. www.hydronicalternatives.com.

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Mike T., Swampeast MO

How I did mine and some numbers:

Myson B-29, chrome hydronic towel warmer.

¾" connections on warmer. Connected as highest farthest element of domestic hot water GRAVITY recirculation loop. Connections about 16' above top of hot water heater. "Supply" portion of loop 1" copper; "return" ½" copper, all neatly insulated with the split, adhesive "foam" type insulation.

Supply temp about 135°, return about 130° WHEN LOADED WITH TOWELS; significantly greater delta t when unloaded.

Towels reach about 93° on the outside; 98° between layers. This takes about 3 HOURS with a fresh, dry towel--about 5 HOURS with towel damp from use. To the skin the towels are slightly warm, soft and decidedly fluffy.

With lower supply temperature (about 120°) it took at least twice as long to get somewhat warm, fluffy towels. Gravity circulation would sometimes STOP in the warmer with the "normal" temperature fluctuation in the hot water heater tank. (There was still some circulation in the recirculation loop itself, but since there is a fixed bypass around the towel warmer to allow circulation when the warmer is turned off, I believe most all heat was flowing through the bypass instead of the warmer.)

I was EXTREMELY dissatisfied with the performance of the warmer at low water temperature. Since everyone else in the house complained constantly (and increasingly bitterly) that I kept the hot water too "cold" for them anyway, I upped the temp to one notch below "hottest".

Literature from Myson and other towel warmer mfgrs. recommend AGAINST the common American practice of installing a warmer in series with a shower/tub insisting they will NEVER deliver towels like they are supposed to produce. Given the time requirement I have seen, I tend to agree whole-heartedly.

Since this is the warmer with 2nd highest output in the Myson line, I was VERY concerned about running it during our hot, humid, disgusting summers--not only because of discomfort, but because of extravagent waste.

While I have not yet done the experimentation to determine the actual flow through the warmer (that's a WINTER project), the VERY low delta t (about 5°) and presumed low flow (remember it's gravity alone) tend to tell me that WHEN LOADED it is not liberating much heat to the room. My senses tell me the same: the A/C keeps the room within design parameters; I can feel neither convection nor radiation from the warmer.

Both chrome and towels have very low emissivity, so even though the warmer is significantly warmer than radiators from which I CAN feel radiation they're simply not emitting much. The design of warmers is intended to "trap" convection "inside" of towels--not to convect to the room. The loops in towels themselves make them very poor at delivering convection. While I know there IS some heat transfer to the space it does not seem significant enough to raise its temperature by even a degree nor does it seem excessively wasteful of fuel.

While I know it is successfully argued that ANY use of energy beyond what is "required" IS pure waste I rationalize that my other energy-saving measures have more than made up for the extravagence. Since the space is proportionally heated, the only "waste" in the winter is the difference in efficiency between the hot water heater (new and well-insulated) and the boiler (old and inefficient).

Recommendations:

You need a nearly constant supply of hot water that averages at least 130° to achieve the real "purpose" of a towel warmer. If you go significantly higher in supply temperature I presume you could cycle the warmer BUT you will still need HOURS to deliver a "proper" towel. If the showering/bathing schedule of the occupants is VERY predictable this should not be too much of a problem...

Many/most hydronic space heating systems in the U.S. aren't really set up to deliver heat in this method. Even if you use a fully modulating boiler the load imposed by a warmer in use is VERY low--so low that buffering is required to prevent either hideous short-cycling of the boiler and/or excessive fluctuation in supply temperature.

It is possible to construct a tiny hydronic system dedicated exclusively to the towel warmer, but the added cost and complexity make this rather foolish in my mind.

IF the supply of domestic hot water is kept quite warm AND circulating this seems a very effective and essentially trouble-free method to attach a hydronic warmer. Since the delta-t of a warmer in use seems VERY low even with gentle gravity circulation it seems to imply that forced circulation has little if any benefit.

Kept under continuous natural circulation and relatively high temperature the chances of Legionella growing in the warmer seem exceptionally remote. The added energy during the non-heating season seems reasonable.

Unless you ALREADY plan for a nearly constant source of fairly hot water, I HIGHLY suggested an oil-filled electric model!

p.s. If you use Myson prepare for pure hell when making the connections leak-free!!!!!!!!!!!

Mad Dog

2 Things to consider.............

1: Stay away from Myson- poor qaulity..tendency to leak
2: Run it on its own loop, so that if either it or the floor tubing ever have a problem, you are not totally out of luck. Mad Dog

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Glen

Thanks for all the info -

some ideas parelleled my own. And - I am leaning towards adding to the radianat loop rather than the DHW. The design came back suggesting that we are short a few btu's in the two main baths - and I am hoping to add a bit of heat via warm towels. Just a thought - we still have some time before we finalize design. thanks again - from the very smokey Canadian rockies

Mike T., Swampeast MO

Watch out

Manufacturers plainly state that you should not consider the towel warmer as part of the space heating system.

While I haven't computed the heat output of the towel warmer the 5° delta t with only GRAVITY for circulation tends to tell me that it is not putting out much heat to the space when loaded.

I believe forced circulation would only result in lower delta t, not an increase in output.

Glen

The alternative -

is to add electric baseboard - as this is not just your avergae cabin in the woods - it may not be appropriate. And - as we are short the btu's only on the coldest days - it should work OK. I do understand your concerns - thanks.

Doug Wagoner

Towel warmers el cheapo', expresso,

I have toyed with towel warmers myself and get excited when I see yet another topic on this subject. I admire the beautiful ornate designs and the craftmanship displayed in the award winning baths exhibited here on the wall. They are a tribite to your expertize and ingenuity. But all the hydronican I have ever engineered still leaves me grappling with the fact that a towel in a $70.00 microwave for 1.5 minutes will produce the same effect at a fraction of the cost. I predict that in a few years microwave towel warmers will be a standard built-in for the discriminating home owner. Set the timer to sound at the end of a 10 minute shower or a 40 minute hot tub soak to let you know your towel(s) is ready. Take one to your wife the next time you hear her in the shower, "just for you sweets". Ahhh, she will know you love her.