Chrome Heated Towell Rail - Good or Bad?

newbie2

Mods feel free if posted in the wrong forum.
Hi, I'm thinking of installing a chrome heated towell rail in my bathroom but I've heard some funny reports regarding the heat they actually radiate. Some people i've spoken to complain that while the rad's are really hot to the touch, they dont radiate the heat outwards - the chrome absorbs it.
Anybody heard of this or has antbody got one of these in their bathroom? Are they worth the cash?
Thanks in advance

Endymion

absorbs it you say? It can only radiate or conduct the heat. Their the same as any raid, you adjust the water flow untill it's heating at the right temperature. People tend to touch them allot more maybe thats why people notice the heat more.

Creamy Goodness

well i have one in my shower room.

the heat doesn't really heat the shower room if you know what i mean so i guess you can say the chrome absorbs it.

they are really nice to have, especially in the winter time when it's hella cold out.

Endymion

chrome isn't magic, the heat goes somewhere. Most likely out a window or through the ceiling. They have less surface area then a standard double raid, so they radiate less, their not really designed around convection so the hot air stagnates. Basically theres nothing wrong with them. They operate as they are ment to. i.e. to dry out towels and the like.

newbie2

Carnivore wrote:

Basically theres nothing wrong with them. They operate as they are ment to. i.e. to dry out towels and the like.

Point taken.
Thanks all for the replies - looks like if I want my bog to be warm I'll have to stick with the original one and stick a towell rack behing the door!

Mellor

The chrome can't absorb the heat, there is no material in the world that absorbs heat when it is hotter than its surroundings. None.
They are just design with a different main purpose

beldin

Well you can get combined ones , a normal radiator with one or 2 bars on top to hang towels on. I have a normal towel rail in my ensuite and it is fine. Only annoying thing is that i didn't fit an electrical element in it so that in summer i have no heated towels

Corkey123

Beldin

My experience is they are good for warming towels, etc, however they are not designed as radiators. You should establish what BTUs your shower room requires before purchasing either a towel rad, rad or both. BTUs are a measurement of the output of radiators, etc.

see the link below to calculate BTU

http://www.diy.com/diy/jsp/bq/templates/content_lookup.jsp?content=/bq_advice/planning_tools/btu_calculator.jsp

secman

I put one in a bathroom, plumber told me it would be sufficient to heat the bathroom. Unfortunately he was wrong, it looks great, but it is noticebly cooler compared to the rest of the house in the winter. As previously stated their purpose is to heat towels not bathrooms, found out the hard way!

air

I was looking at chrome radiators before & IIRC I think that it was mentioned that you need to double the size of your rad to get equivalent output with a chrome radiator versus a normal one.
Radiators "radiate" heat amazingly enough, and putting a shiny surface on a radiator will reduce its ability to radiate, hence why your kettle is typically silver and not black - it reduces heat loss.

FrankGrimes

I'm fairly certain that radiators actually convect heat and the name 'radiator' is misleading as a result.

I was in buying a designer rad in Heating Distributors in Finglas last week and the saleswoman said chrome rads reduce the BTU output by 10%.

By nature of their layout towel rads have siginificantly lower BTU output than a normal rad with the same external length and width. And with chrome it's lower again.

As Martin suggested, calculate your BTU requirements and work off that.

My bathroom is about 2.2 metre by 2.5 metre and is well insulated - we find that the heat from the chrome towel rad actually heats this room fine, but for a larger bathroom don't rely on it as a single source of heat.

I'd like to add an electric element to the chrome towel rad and have the ability to do this as the stud wall behind it is currently open (no slab yet) - what do I need to add (will get the electrician to wire it when he's wiring the extension this weekend) and do the element fittings come in chrome?

air

Yes the water to air heat transfer is primarily by convection on the outside of course, with some minimal radiation also.The colour difference still makes an impact on the heat transfer from the water inside the pipe to the air outside the pipe. Whatever the exact physics are, we are agreed that the chrome reduces the heat output, I have no hard figures on the actual reduction for two radiators that are identical except for finish.

beldin

As I said you can get combined ones. These have a radiator as well as some rails overhead to heat towels on.
http://www.bathroomstuff.co.uk/iqs/dbitemid.22/sfa.view/column_radiator_towel_rails.html

These have their output specified so use martins calculator and see if any of these would heat your room. I know tubs and tiles do some of them so maybe check what they have.

FrankGrimes

look nice if that's the style you're after, but very pricey.

I picked up mine which is a modern style chrome one (i.e. looks kinda like a ladder) and is quite large for €199 in Clondalkin Builder Providers there last year. That's an awful lot cheaper than I'd seen them in bathroom stores, but I thik B&Q might even be cheaper again.

Mellor

I still think the poorer performance of chrome rads is still more down to the shape and not the finish.
A normal and chrome rad with the same dimensions are NOT the same size/area.

tred

secman wrote:

I put one in a bathroom, plumber told me it would be sufficient to heat the bathroom. Unfortunately he was wrong, it looks great, but it is noticebly cooler compared to the rest of the house in the winter. As previously stated their purpose is to heat towels not bathrooms, found out the hard way!

my brother is in the plumbing trade. he told me you need to have a normal rad to heat the bathroom, and then with a towel rad, to dry the towels. if you have any decent size bathroom.

Endymion

Right; How rads work.

Rads radiate heat, which in turn heats the surrounding air, this heat rises, cooler air decends and is heated by the rads radiated heat. This sets up a convection current which heats the room. Due to both how towel rails are designed and how they are used, they have reduced surface area, making for reduced convection currents, which leads to less heat spreading through out the room. It's not that less heat is produced, it that it's not very well disipated throughout the bathroom. If it was, the towel rail would be useless as a towel rail.

Good rads have good air flow. Good towel rails don't

Ps ignore all comments about finish, the effect is insignificant to the level of being non existent.

Do-more

The other thing of course, is that towel rads normally have towels on them! It's like having a nice insulating jacket on your rad and the heat can't get out to heat the room.

Best combination I think is a nice towel rail and underfloor heating so your tutsey's are nice and warm when you step out of the shower.:D

air

I'd imagine that the majority of the heat transfer between the rad and the air is by conduction through the wall of the pipe, followed by convection in the surrounding air. I explicitly discounted the different usage patters - as I mentioned above, I was considering "two radiators that are identical except for finish". The radiative heating I'd imagine is pretty low as a proportion of total output but finish would have a big impact on this portion of the emission. For practical purposes in a radiator it could well have a negligible impact.

Endymion

air wrote:

I'd imagine that the majority of the heat transfer between the rad and the air is by conduction

Please do not take offense to what I'm about to say. It's been pointed out that I can be abrassive. But you are wrong, Look up what conductions is and you will see that you do not get conduction between two separate bodies. conduction is the transfer of internal energy from a region of higher temperature to one of lower temperature through means of stimulating adjacent particles in a body.

I explicitly discounted the different usage patters - as I mentioned above, I was considering "two radiators that are identical except for finish". The radiative heating I'd imagine is pretty low as a proportion of total output

I found this link, it agress with what iv'e said so far up thread.

but finish would have a big impact on this portion of the emission. For practical purposes in a radiator it could well have a negligible impact.

One of the first third level experiments I did was to test how well different finishes absorbed or reflected energy. yes theres is a different in finish, no its not major. Your understanding on how it affected heat transfer is also lacking. the inside of the towel rail is black, "good for absorbing radiated heat, the outside is shinny or white, good for reflecting heat into the room.

air

Carnivore wrote:

good for reflecting heat into the room.

Reflecting heat into the room? What are you on about? Surely you meant to say radiating, which a silver surface is definitely not suited to.

Furthermore what two seperate bodies are you talking about? I was referring to conduction between the inner surface of the radiator pipe and its outer surface?

Furthermore, your quote of me above amounts to quoting out of context, the abstract which you quoted appears to make no sense, whereas my complete sentence does make sense.

Mellor

Every object that gives out heat gives it out in all three ways, conduction, convection and radiation. The amount of each it gives out depends on the object.
Obviously you could set up certain situations where this wont happen, but this will not occur in the real world. Only in a lab book

cormac_byrne

Carnivore wrote:

you do not get conduction between two separate bodies.

Err Yes you do

see http://en.wikipedia.org/wiki/Heat_conduction
note the phrases

... So, when dealing with a multilayer partition ....

and

... When heat is being conducted from one fluid to another through a barrier ...

Technically radiators transfer heat from water to metal to air via conduction.
The heated air then travels around the room by convection. there is little or no radiation involved.

Mellor

cormac_byrne wrote:

Technically radiators transfer heat from water to metal to air via conduction.
The heated air then travels around the room by convection. there is little or no radiation involved.

The air is heated by conduction as well as radiation. And this warm air heats the room through convection currents.
Any hot surface radiates heat. Anything that gives out infa-red light/radiation.
As I previously said rads give out heat in all three forms.

cormac_byrne

Heat is given off when an object's thermal energy is transferred. Thermal energy (see below) can be transferred in three ways:

by conduction, by convection, and by radiation.

1. Conduction

Conduction Example (Game of Pool)

Conduction is the transfer of energy from one molecule to another. This transfer occurs when molecules hit against each other, similar to a game of pool where one moving ball strikes another, causing the second to move. Conduction takes place in solids, liquids, and gases, but works best in materials that have simple molecules that are located close to each other. For example, metal is a better conductor than wood or plastic.

Convection Example (A Radiator Emiting Heat)

2. Convection

Convection is the movement of heat by a liquid such as water or a gas such as air. The liquid or gas moves from one location to another, carrying heat along with it. This movement of a mass of heated water or air is called a current.

3. Radiation Radiation Example (Sun Bathing)

Heat travels from the sun by a process called radiation. Radiation is the transfer of heat by electromagnetic waves. When infrared rays strike a material, the molecules in that material move faster. In addition to the sun, light bulbs, irons, and toasters radiate heat. When we feel heat around these items, however, we are feeling convection heat (warmed air molecules) rather than radiated heat since the heat waves strike and energize surrounding air molecules.

---

Yes everything that's above absolute zero radiates heat, or emits infra red to put it another way.

Radiant energy is proportional to the fourth power of the absolute temperature of the source.

To get a significant amount of IR from an object it needs to be quite hot (generally glowing as per the examples light bulb and toaster above)

squire1

Wow, you learn something new every day.

OP. If you want to warm towels get a heated towel rail, that's what they do. If you want to warm the room get a radiator, that's what they do.:cool:

Endymion

Air; I'm tired replying to you. Shinny reflects heat, dull absorbs heat. The outside to the towel rail is shinny, so the outside reflects the rediated heat, the inside is dull so it allows heat to pass easily from the water to the steal.

cormac_byrne; Your link is broken, and I have my doubts that you understand any of what you just posted. Conduction requires the interaction of molecules, air molecules don't interact with the crome molecules, they don't bounce off each other in any significant way. I've read nothing in what you posted that suggested conduction exists between two seperate bodies. Heat transfer is therefore through radiation.

ps, don't quote wiki, and certainly never use it to contradict someone.

Pss the reason I don't think you understand what you quoted was the "Radiant energy is proportional to the fourth power of the absolute temperature of the source." coment. Thats a matierial specific comment.

Psss your definition of conduction is pretty shockly over simplified.

Mellor; It wouldn't be right to say that rads convect heat through a room. Convection is how heat is disipated throughout the room. But, meh, you seem to get the idea at least.

air

Carnivore wrote:

Air; I'm tired replying to you. Shinny reflects heat, dull absorbs heat. The outside to the towel rail is shinny, so the outside reflects the rediated heat, the inside is dull so it allows heat to pass easily from the water to the steal.

Again, reflects? Surely you mean radiates?
The latter half of your sentence above makes no sense - "the outsides reflects the rediated heat" - reflects it from where exactly? Fair enough if there is heat energy incident on the outside of the radiator from another source it could reflect it, the heat from within it would be radiating - not reflecting.
Your poor spelling, attitude and lack of any supportive sources - not even the wiki's you condemn, lead me to believe you dont have a clue. If something is "shockingly over simplified" then why dont you explain it in further detail?
Finally, how qualified are you to contradict anyone? Do you hold any qualifications of relevance in physics?

Endymion

air wrote:

Again, reflects? Surely you mean radiates?
The latter half of your sentence above makes no sense - "the outsides reflects the rediated heat" - reflects it from where exactly? Fair enough if there is heat energy incident on the outside of the radiator from another source it could reflect it, the heat from within it would be radiating - not reflecting.

Reflects the radiated heat. This is my third time saying it. Scource radiates heat, shinny layer reflects heat away from source. Ps look up what radiate means.

Your poor spelling, attitude and lack of any supportive sources - not even the wiki's you condemn, lead me to believe you dont have a clue.

Thats your opinion. Your welcome to it.

If something is "shockingly over simplified" then why dont you explain it in further detail?

Metals are good conductors due to the nature of their atomic bonds. "simple molecules" is really a moronic term you might use to explain something to children. Also the "bouncing off each other" idea is miss leading.

Ps I've allready given my definition of conduction.

Finally, how qualified are you to contradict anyone? Do you hold any qualifications of relevance in physics?

I recieved an A1 grade in leaving cert physics. Also as part of my general engineering course I've studied Thermodyanmics and Material science.

Mellor

Carnivore wrote:

Mellor; It wouldn't be right to say that rads convect heat through a room. Convection is how heat is disipated throughout the room. But, meh, you seem to get the idea at least.

Sorry is I wasn't clear enough, but I think you understand me. The room is heated through convection, and the air through conduction and radiation.

Fel this thread has got away from the original point. Towel rail rads not worse than regular one. They just do a different job. Also, a towel rad measuring 1200 x 1000 is not the same size as a regular rad 1200 x 1000, so all comparisments are skewed from the start.

Victor

Carnivore wrote:

Look up what conductions is and you will see that you do not get conduction between two separate bodies.

So how does the heat get from the metal heating element on a cooker to the metal saucepan?

Endymion

Well that would be conduction and radiation victor, with the bulk transfered through conduction. Why do you ask. Do you have a cooker problem? Oh I see.

tapest

Hi guys
This is not intended to add fuel to this heated (lol) discussion, rather a trip down memory lane.
In the old days radiators "radiated" heat, with the little convection you get when any heated object is exposed to cooler air. Then came the modern efficient rads, with little boxes on their back panels, acting like mini chimney flues to enhance air movement. This were actually called "convector radiators" and during the transition period you had to specify which type you wanted. In fact there was a time when skips were full of panel rads with people converting just the rads.
I know I'm old
t

311

I only read the first few posts ,the towel rails are only for decorative purposes really ,they arent designed for heat output.

If you look at standard radiators they have fins on the back or in the middle ,the convection currents caused by these actually pull in cold air from the bottom of the radiator because they push warm air up .Your room actually heats in a circular motion with convector radiators .

Towel rads are just bars that heat up ,the surface of the towel rad alone says it all . Even an old non convector rad is better than a modern towel rad ,as the heated surface is about 50-60% more.

There are radiators that come with a rail at the top ,nothing special ,but great for bathrooms that have two outside walls.

Brian.

ircoha

Carnivore wrote:

Ps ignore all comments about finish, the effect is insignificant to the level of being non existent.

TRex: you describe your self elsewhere as being regarded as being abrasive: never Man, u a pussy cat:D

if your statement above is true, please explain the comment in the following link
http://www.myson.co.uk/specifications.pdf

For the hard of hearing, I have posted the salient line here:
Chrome outputs reduce by approximately 35%.

If it not the finish, then wtf is the reason?

311

The op is asking if a towel rail is good or bad,
The towel rail rad is good at making your en-suite,bathroom look well .
The towel rail rad has a very very bad heat output .regardless of whether it's painted with thick chrome paint or heat emmiting white enamel paint.

Would strongly suggest against one if it's for a bathroom with two outside walls, an en-suite with one oustside wall may not be so bad.

Endymion

ircoha wrote:

TRex: you describe your self elsewhere as being regarded as being abrasive: never Man, u a pussy cat:D

if your statement above is true, please explain the comment in the following link
http://www.myson.co.uk/specifications.pdf

For the hard of hearing, I have posted the salient line here:
Chrome outputs reduce by approximately 35%.

If it not the finish, then wtf is the reason?

When I talk about finish, I mean finish, as in dull/ dark/ shinny. There will be very little difference between hightly polished shinny chrome, and dull chrome, with regards to heat transfer though the upper layer to the outside world. However shinny finishes reflect heat away, just like in that farscape episode where criton had a shinny shield to reflect the heat.

anyway, in a rush, have to go, sorry for short insane answer.

hey, thanks for asking.

ircoha

_Brian_ wrote:

The op is asking if a towel rail is good or bad,
The towel rail rad is good at making your en-suite,bathroom look well .
The towel rail rad has a very very bad heat output .regardless of whether it's painted with thick chrome paint or heat emmiting white enamel paint.

Would strongly suggest against one if it's for a bathroom with two outside walls, an en-suite with one oustside wall may not be so bad.

The OP is asking about Chrome Heated Towel Rail, not just about towel rails.

The link i provide elsewhere in this post clearly states that chrome output is 35% less than normal, where the normal is white enamel paint and the chrome is a metal finish, not a paint.

What would be nice to know is why Chrome output sucks

ircoha

Carnivore wrote:

When I talk about finish, I mean finish, as in dull/ dark/ shinny. There will be very little difference between hightly polished shinny chrome, and dull chrome, with regards to heat transfer though the upper layer to the outside world. However shinny finishes reflect heat away, just like in that farscape episode where criton had a shinny shield to reflect the heat.

anyway, in a rush, have to go, sorry for short insane answer.

hey, thanks for asking.

Okay T-Rex, sorry u had to rush, heard a few Brontosaurus scream after you went [ a la Robin Williams in Mrs Doubtfire:)

What you are saying is that there is very little difference in chrome finishes which is cool:D My other post asks why chrome sucks

311

ircoha wrote:

The OP is asking about Chrome Heated Towel Rail, not just about towel rails.

The link i provide elsewhere in this post clearly states that chrome output is 35% less than normal, where the normal is white enamel paint and the chrome is a metal finish, not a paint.

What would be nice to know is why Chrome output sucks

LETS PAINT ALL RADIATORS WITH BLACK EMULSION PAINT .

311

If I try to heat 1kg of metal ,it will take longer than heating .75KG of metal.

Chrome is not paint ,Chrome is a metal.

Mellor

_Brian_ wrote:

.
The towel rail rad has a very very bad heat output .regardless of whether it's painted with thick chrome paint or heat emmiting white enamel paint.

_Brian_ wrote:

.
Chrome is not paint ,Chrome is a metal.

Can you explain your two completely opposed comments please.
Nobody ever suggested that chrome wasn't a metal. Or that 1kg heats up any quicker than .75kg
Kinda lost me with your last comments.

311

If I've lost you I'm sorry ,let me call someone who gives a ****

311

Mellor wrote:

Can you explain your two completely opposed comments please.
Nobody ever suggested that chrome wasn't a metal. Or that 1kg heats up any quicker than .75kg
Kinda lost me with your last comments.

The fact that this thread is still snailing along ,what type of comments do you expect to get .Getting anal about whether or not the chrome was painted on or electrical charged on ,I don't make them ,I install them.

Typical comments from someone who just started college or something.

Endymion

jesus this thread should ide.

but not today. "Chrome" as far as I remember is some alloy comprising iron and carbon andanothe metal actually called chrome. It has certain properies, one of which is being stainless, i.e. not rushing, which is good, considering it's going in the bathroom. Chrome could easily have a lower conductivity then normal steal, I honestly don't know.

Mellor

Chrome is a metal such as steel or nickel that has been plated with chromium.
The alloy that you are thinking of carnivore, (iron, carbon and chromium), is actually stainless steel.

This thread is dead, gone down the road of people giving information that they don't believe themselves.

I vote to close it.

Endymion

Mellor wrote:

The alloy that you are thinking of carnivore, (iron, carbon and chromium), is actually stainless steel.

This thread is dead, gone down the road of people giving information that they don't believe themselves.

I vote to close it.

In fairness I did say as far as I remember. Thanks for clearing that up though, I had been wondering what the differnce was between stainless steal and chrome, matierial wise.

Anyway, yea, the Op's orginal question where answered on page one.

Thread closed.

cormac_byrne

I said earlier that most of the heat leaving a radiator is by conduction (and then around the room by convection)

Mellor said that all things radiate heat and he is correct in that

I said that radiant heat output is only significant when things get really hot
"proportional to the fourth power of the absolute temperature of the source"

(e.g. old fashioned electric bar heater with shiny chrome reflector behind it)

After doing a bit more reading I realise that the radiant output in a radiator could be more significant than I was giving it credit for.

irocha wonders where 35% of the heat output can go if you replace an enamel paint finish with chrome.

Finish can have little effect on the conductivity of a material, so there has to be a different answer.

The answer is 'emmissivity'

Emissivity is the ability for radiant heat to leave the surface of an object. It matters not what the density, mass or thickness of the object, only the surface. As can be seen below, emissivity (E factor), plays a significant role in how heat moves.

Chrome .05 poor -> paint .94 excellent

EMISSIVITY OF VARIOUS COMMON MATERIALS

Material Emissivity value

Gold, polished .03
Metalized Film Radiant Barrier .04
Silver, polished .04
Chrome .05
Aluminum, polished .04
oxidized .78
Brass, polished .04
oxidized .61
Iron, polished .21
oxidized .69
Copper, polished .05
oxidized .78
Human skin .98

EMISSIVITY OF BUILDING MATERIALS

Wood .95
Glass .94
Paint, average of 16 colors .94
Brick, common red .93
Concrete .92
Plaster, rough coat .91

Endymion

So I was right? Carnivore ftw.

Ps, I'm still not too sure you knwo what your are saying

cormac_byrne

Carnivore wrote:

So I was right? Carnivore ftw.

Ps, I'm still not too sure you knwo what your are saying

No you're wrong and clearly don't understand either what I'm saying or what you're saying.

Carnivore wrote:

chrome isn't magic, the heat goes somewhere. Most likely out a window or through the ceiling

WRONG: it's Emissivity see above, Chrome .05 poor vs paint .94 excellent

Carnivore wrote:

Rads radiate heat, which in turn heats the surrounding air, this heat rises, cooler air decends and is heated by the rads radiated heat. This sets up a convection current which heats the room

WRONG: that's a perfect description of how radiators <b>conduct</b> heat
(yes I know they radiate some heat also)

Carnivore wrote:

ignore all comments about finish, the effect is insignificant to the level of being non existent

WRONG: see emissivity above & manufacturers specs detailing 35% difference

Carnivore wrote:

Look up what conductions is and you will see that you do not get conduction between two separate bodies

WRONG: I did look it up and pointed you to a very clear wikipedia article

Carnivore wrote:

the inside of the towel rail is black, "good for absorbing radiated heat, the outside is shinny or white, good for reflecting heat into the room.

WRONG: Radiators do not 'reflect' heat from within, they either conduct or radiate heat, as per the materials conductivity & emissitivy. Heat directed at the radiator, say from the bathroom light bulb will be absorbed or reflected depending on the reflectivity of the radiator surface, but that's not of any relevance to the functioning of the rad itself.

Carnivore wrote:

Shinny reflects heat, dull absorbs heat. The outside to the towel rail is shinny, so the outside reflects the rediated heat

WRONG: again we're talking radiated not reflected heat and chrome radiated less well than paint

Carnivore wrote:

cormac_byrne; Your link is broken

No it's not (wiki pages can be a bit slow to load though)

Carnivore wrote:

I don't think you understand what you quoted was the "Radiant energy is proportional to the fourth power of the absolute temperature of the source." coment. Thats a matierial specific comment.

WRONG: N.B. I did not say 'directly proportional'

Victor asked "So how does the heat get from the metal heating element on a cooker to the metal saucepan?"

Carnivore wrote:

Well that would be conduction and radiation victor, with the bulk transfered through conduction. Why do you ask. Do you have a cooker problem? Oh I see.

OK, you got that one right, but that's a direct contradiction of

Carnivore wrote:

Look up what conductions is and you will see that you do not get conduction between two separate bodies

Carnivore wrote:

However shinny finishes reflect heat away, just like in that farscape episode where criton had a shinny shield to reflect the heat.

So you were watching farscape when you shouldd have been studying your 'Thermodyanmics and Material science'

Out of curiosity was the heat source external or internal?

Endymion

I really care not how wrong you think I am, I answered the OP's questions correctly. It also seems to me that your knowledge is solely based on what you have read off wiki.

You said radiated heat was perportional to the square of blah blah blah bull****, I said it's material specific, you now agree with that. I was right, you wrong, ergo carnivore ftw.

btw it was an external scource and I was being flippen.