Towel Rad Inadequate

[BrianC]

Good afternoon all, sorry if this seems like a stupid question but I am looking for advice. We recently had our bathroom done and were advised a Radox RXPS-1800400-CH would be man enough to heat the room. It isn’t, having done a bit of homework I think I’m going to go down the route of a convector radiator, the rest of the rads are convector rads. Is this the way forward?

 

[Gasmk1]

what size is bathroom

 

[Tim Watts]

I'm not a plumber (well I DIY some) but I did design my heating system

The best thing to do is look at the quoted output of the radiator or towel rail in watts. This will usually be quoted at a "delta T 50C" (delta may be written as the greek letter, a triangle).

So the bigger this number, the more heat you'll get out. Towel rails are poor - you'll be looking at 100-200W for a typical size. A finned single panel radiator of the same size will beat it by a significant factor.

My rule of thumb: if you have some idea how much heat it takes to keep the room warm, look for a radiator quoting 1.5 times as many watts at Delta-T 50C. If you want a cold room to heat up fast, add another 50% or more.

Cheers, Tim

Now - if you want to do actual calculations: (I apologise if this is egg-suckage, but if you're not aware)

"Delta-T 50C" means that when the average radiator temperature will be 50C above the room temperature, the heat output will be X watts.

No one designs to Delta-T 50C any more as the boiler will be running beyond its efficient point for a modern condensing type (where it wants the return to be less than about 55C - a little cooler is even safer/better)

A modern condensing boiler will more likely be running at roughly 60-flow/50-return or 65/55 at best, so your radiator temperature will be average of those, so 55C to 60C. If you're interested in heat output to maintain the room at 20C, that's a Delta-T or difference of 35C to 40C.

Delta-T 40C gives about 75% of the heat output compared to Delta-T 50C. Delta-T 35C is about 65% (some numbers I found online once).

So if you have some idea how much heat it takes to do the job, look for a radiator quoting 1.5 times as much at Delta-T 50C.

 

[townfanjon]

Bain of my life these things , its a “ towel rail” not a radiator.

 

[Chuck]

Good afternoon all, sorry if this seems like a stupid question but I am looking for advice. We recently had our bathroom done and were advised a Radox RXPS-1800400-CH would be man enough to heat the room. It isn’t, having done a bit of homework I think I’m going to go down the route of a convector radiator, the rest of the rads are convector rads. Is this the way forward?

No one can really answer this without knowing heat loss and usage patterns for your bathroom.

600-800W (which is what your model seems to promise) should be enough to heat a typical medium-sized bathroom. Of course if you insulate it by covering it with towels it may struggle. I like one heated and one unheated towel rail in each bathroom for this reason. I also like heated towel rails to be dual fuel, on a CH loop that is not shut off by zone valves and controlled by a TRV. The electric heater is on a four-hour countdown timer that is just outside the door to help in the autumn/spring when the CH is not on for much of the time and the bathroom needs a boost. Use the heated rail to dry the towels after bathing but move them to the unheated rail so the rail can act as a heater.

 

[BrianC]

what size is bathroom

3400mm X 2120mm, there are two external walls, one window and a tiled floor.

 

[Gasmk1]

my towel rad is 860 watts and is more than adequate but then again i do have underfloor heating in there and it has no outside walls

 

[Tim Watts]

Bain of my life these things , its a “ towel rail” not a radiator.

Yep. You can just about get away with a typical towel rail for heating with an tiny islanded bathroom right in the centre of the house like I have (and assuming the ceiling is warm or insulated, not onto a cold roof space). Anything else would be unlikely to work well unless you have other heating as well.

Edit: that's not to say you couldn't find a massive towel rail with a decent output of course - just thinking the typical type here...

 

[Gasmk1]

i think the towel rad is about the right size but it depends on how many towels you have. never like normal rads in bathrooms as they corrode very quickly

 

[townfanjon]

3400mm X 2120mm

No chance pal , have you room for a rad and a towel rail?

 

[BrianC]

No one can really answer this without knowing heat loss and usage patterns for your bathroom.

600-800W (which is what your model seems to promise) should be enough to heat a typical medium-sized bathroom. Of course if you insulate it by covering it with towels it may struggle. I like one heated and one unheated towel rail in each bathroom for this reason. I also like heated towel rails to be dual fuel, on a CH loop that is not shut off by zone valves and controlled by a TRV. The electric heater is on a four-hour countdown timer that is just outside the door to help in the autumn/spring when the CH is not on for much of the time and the bathroom needs a boost. Use the heated rail to dry the towels after bathing but move them to the unheated rail so the rail can act as a heater.

 

[SimonG]

A towel rail is exactly that. Any supposed heat outputs are gonads. Damp towel goes on and immediately any rated output goes through the floor.
A radiator and towel rail in combination are the best or radiator only if no room allows.

 

[Tim Watts]

600-800W (which is what your model seems to promise) ...

at a pretty hot water flow temp (dT-50C/dT-60C) - if the OP runs his system at condensing temperatures, could be more like 400W

 

[ShaunCorbs]

As above if towels are going on it then you need a second rad / underfloor elec heating

 

[BrianC]

No chance pal , have you room for a rad and a towel rail?

If I was to get rid of the towel rail and replace it with a radiator would I be looking for a convector radiator as the rest of the ones in the house are or could I go for a a more contemporary designer? Bearing in mind I am looking for an 1800mm vertical by about 400-500.

 

[BrianC]

i think the towel rad is about the right size but it depends on how many towels you have. never like normal rads in bathrooms as they corrode very quickly

We haven’t been putting any towels on it as it simply isn’t throwing enough heat out to warm the room.

 

[Tim Watts]

If I was to get rid of the towel rail and replace it with a radiator would I be looking for a convector radiator as the rest of the ones in the house are or could I go for a a more contemporary designer? Bearing in mind I am looking for an 1800mm vertical by about 400-500.

I have a few of these: Ultraheat - Tilbrook - they have decent heat outputs for the size (one of the best I could find). There are other styles too from that manufacturer. Expensive mind...

 

[Gasmk1]

https://www.NoLinkingToThis/p/acova-2-column-vertical-radiator-2000-x-398mm-white/46099

something like this

 

[BrianC]

I have a few of these: Ultraheat - Tilbrook - they have decent heat outputs for the size (one of the best I could find). There are other styles too from that manufacturer. Expensive mind...

Are all radiators convectors? If not, what are the benefits/drawbacks?

 

[Tim Watts]

Are all radiators convectors? If not, what are the benefits/drawbacks?

Yes - in that they *mostly* lose heat by convection. Technically they do radiate heat too, but this is relatively small amount (10-20%)

 

[BrianC]

what size is bathroom

What BTU rating at T50 would you suggest?

 

[Welder]

Bain of my life too Town.

Some information. Chrome plated or polished stainless warmers put out less heat than white. These are not designed to heat the space. They, unsurprisingly, are designed to warm towels.

Just look at the difference in design of a radiator and a warmer. The surface area of a radiator is what makes it an effective heat source and that's orders of magnitude more than a warmer.

If you have a cold bathroom you will need suplementary heating in the form of underfloor heating or a proper (separate) radiator.

 

[Best]

A combined radiator/towel rail is a good choice

 

[Rob Foster]

If I was to get rid of the towel rail and replace it with a radiator would I be looking for a convector radiator as the rest of the ones in the house are or could I go for a a more contemporary designer? Bearing in mind I am looking for an 1800mm vertical by about 400-500.

There are combined towel rad and convector rad available
Rob Foster aka centralheatking

 

[Tim Watts]

What BTU rating at T50 would you suggest?

Sorry - don't do BTUs But in watts...

At a room size of 3x2m, 2 external walls (cavity with blown fibre insulation), double glazed, ground floor so warm ceiling, I reckon 1.5kW to 2kW of real power. So 1.5 times that for a dT-50C figure.

That's based on real life measurements (I used to heat my house with electric oil filled rads, so have a very good idea of power required).

Your mileage may vary depending on building type, insulation, windows and so on.

But with radiators, you cannot every have "too big" - so the biggest that you can get in the space is a good guide, without going completely OTT.

Beware, radiator outputs per unit area vary a lot. Double panel double finned are pretty decent. Triple panel tend to be humongous lumps.

 

[BrianC]

There are combined towel rad and convector rad available
Rob Foster aka centralheatking

In all honesty I think we’re going to forego the towel rad element. We just want a warm bathroom.

 

[Rob Foster]

In all honesty I think we’re going to forego the towel rad element. We just want a warm bathroom.

Bali in the bathroom ! An old centralheatking tv ad. Chking

 

[gmartine]

As Gasmk1 suggests swap the towel rail out with a column rad of the correct output.

 

[oz-plumber]

Some of the vertical rads have attachments that you can hand a towel on. You will lose on radiation heat but the convection heat reduction would be minimal due to towels not blocking the airflow.

 

[Bogart]

Use a normal rad with one of those thingys you can hang towels of hooked on the top. If you have a cat too you can get a cat basket that hangs by the same method.

 

[Frelon]

"We just want a warm bathroom."

Understand that completely, and to have warm towels!

I have a Zehnder Roda Spa radiator in my bathroom, absolutely fantastic. Does what it says on the box! Pricey, but in my opinion (and Mrs Frelon's) worth every penny!

 

[Jack bIRCHLEY]

Hello all.
Reading the towel rail thread touched a nerve as we were thinking of getting the old rads changed to upright ones.
We need to replace old and inefficient radiators in our house. The current ones look like they have been there since late 60s early 70s.
In a newish extension we have modern radiators that seem to be far more efficient, but to make space in the living room we are thinking about fitting slimmer and higher vertical rads, does the towel rail, not much use theory come into play.
Any thoughts on this would be appreciated.

 

[Chuck]

Any thoughts on this would be appreciated.

I think you should start a new question and make it a bit clearer what you are asking because I, for one, am not sure.

 

[Jack bIRCHLEY]

I think you should start a new question and make it a bit clearer what you are asking because I, for one, am not sure.

I think you should start a new question and make it a bit clearer what you are asking because I, for one, am not sure.

My question is, are the upright radiators efficient or are they as much use as a towel rail for heating.

 

[Ben-gee]

As far as towel rails go (I know they're not that manly at pushing out heat) - I find you get a disproportional benefit when you go from 400 width to 600 width. The reason being that you now only need to fold the towel once (in half), whereas on a 400 needs folding into three, this thicker bundle of towel kills room heating dead.