Proabably been asked a zillion times before.. but why are hot-water 'radiators' always painted white? Every physics book tells us that a dark-coloured surface will radiate about 50-100% more heat than a white or silver one at the same temperature.
..and while it's true that they aren't strictly radiators but convector heaters, the same must still apply to some degree.
It does seem a bit pointless taking steps like inisisting on condensing boilers, when the use of white 'radiators' must be pushing-up the needed water temperature for any given room heat, and thereby making the boiler itself less efficient than one working at a lower water-temperature.
While matt-black panels wouldn't suit everyone aesthetically, it's reasonable to suppose that a darker colour such as blue would offer some efficiency advantage over white. There is also the point that radiated heat has a much greater perceived 'comfort value' than convected heat, hence a dark radiator -with twice the radiant output- would create an impression of better functioning even for the same overall heat output.
Has anyone done any accurate measurements on this, I wonder?
..and while it's true that they aren't strictly radiators but convector heaters, the same must still apply to some degree.
It does seem a bit pointless taking steps like inisisting on condensing boilers, when the use of white 'radiators' must be pushing-up the needed water temperature for any given room heat, and thereby making the boiler itself less efficient than one working at a lower water-temperature.
While matt-black panels wouldn't suit everyone aesthetically, it's reasonable to suppose that a darker colour such as blue would offer some efficiency advantage over white. There is also the point that radiated heat has a much greater perceived 'comfort value' than convected heat, hence a dark radiator -with twice the radiant output- would create an impression of better functioning even for the same overall heat output.
Has anyone done any accurate measurements on this, I wonder?
) but in practice I don't think it would make much difference to a domestic radiator.
