White Towel Rad - More BTU Than Chrome One Of Same Size????

[Whitespirit66]

Can anyone tell me the reason for a white towel rail giving out hundreds more BTUs than a chrome one of the same size?

Eg. A 1500 X 600 towel rail in white gives 2839BTU, but the chrome version is only 1945BTU. A big difference just because of different finishes. Or, are the rails of different construction? There is a big difference in output between all white and chrome rails.

I must have been asleep at college when the reason for this anomaly was discussed.

 

[D_Hailsham]

Can anyone tell me the reason for a white towel rail giving out hundreds more BTUs than a chrome one of the same size?

It's all to do with the emissivity of the surface. If you point an IR thermometer at the white surface, it will register a higher temperature than the chrome surface, even if the water temperature is the same.

Didn't they teach you about black-body radiation?

 

[gaswizzard]

Most paint finishes regardless of colour have high emissivities (.09 to 0.95) , but some metallic finishes can have much lower values unless used in conjunction with certain varnishes.

 

[Richard C]

Eg. A 1500 X 600 towel rail in white gives 2839BTU, but the chrome version is only 1945BTU.

Are you sure those figures are correct I agree there will be some difference in emissive values between different finishes but I can’t see how it could possibly be as much as 30% like for like!

 

[David937]

Chrome: http://www.screwfix.com/p/flat-ladder-towel-radiator-chrome-700-x-400mm/26726

176w

White: http://www.screwfix.com/p/kudox-flat-white-towel-radiator-700-x-400mm-259w-884btu/53905

259w

 

[Beerlover]

The best heated towel rail on the market is a standard towel rail (or 2) hung over a proper radiator. A warm towel is nice, but a warm room is better!

IMHO a fancy towel rail ONLY works if linked to UFH and with an electric heater for use in the warmer month (s) of summer.

 

[muggles]

Intriguing, and it's not a typo as it's the same on the Kudox website, and the larger version has similar differences - 1757BTU for white, 1177BTU for chrome. Got to admit I've never noticed that before. Does seem to be a theme though, just looked at another manufacturer's website and they also give much higher outputs for white than chrome.

 

[D_Hailsham]

Are you sure those figures are correct I agree there will be some difference in emissive values between different finishes but I can’t see how it could possibly be as much as 30% like for like!

Emissivity of Common Materials

Polished chrome = 0.058
Copper Polished = 0.023 to 0.052
Copper heated and covered with thick oxide layer = 0.78
Paint = 0.96

 

[Richard C]

Are you sure those figures are correct I agree there will be some difference in emissive values between different finishes but I can’t see how it could possibly be as much as 30% like for like!

Emissivity of Common Materials

Polished chrome = 0.058
Copper Polished = 0.023 to 0.052
Copper heated and covered with thick oxide layer = 0.78
Paint = 0.96

Interesting, I did have a wee search but couldn’t find anything. I would never have though it would make so much difference & I’m a bloody qualified engineer.