On 25/10/2009 19:51 Andrew Gabriel wrote:

Do the same check on other rooms in the house.
If they are all similarly over-spec'ed, you really need to do the same.

They're all based on the original 1967 installation (pre insulation)
sizing. We don't have any problems getting the house up to temperature
in good time on cold days.

Other factors are that radiator outputs are often given using unreasonably
high delta-T values. What delta-T is yours specified at, and what temp do
you actually run your boiler?

From the website: 'All radiator outputs are calculated @DT50°C inline
with European BS EN 442 testing standard'.

It's a Worcester Bosch 24(?) Ri and hasn't got a dial marked with the
temperature, just 'Reset' and 'max'. I just run it as low as it will go
without the house taking for ever to warm up. It's a little less than
half way between the minimum (35C) and maximum (82C), so say 50C?

Have you got a condensing boiler?

Yes.

If so, oversized radiators can make for
more efficient operation (providing they're all similarly oversized).

OK, so the radiators I've looked at are around 5% or 10% oversized
according to the calculator.

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F