On Sun, 10 Aug 2008 19:13:37 +0100, "Roger Mills"
wrote:

Adding up the ratings of the radiators is putting the cart before the horse.
You need to start by working out the heat losses for each room, and *then*
choose suitable radiators for each room. The boiler needs to have sufficient
capacity to meet the total heat loss, plus some for pipe losses, plus some
for transient conditions (getting the house up to temperature from cold,
fairly quickly) plus some for hot water.

Sorry, perhaps I should have made myself clearer. I used one of the
online calculators which asks for room size, whether it's north
facing, if it is double glazed, etc. and told me the radiator size
that room requires. It was those figures I have added up. Whether the
radiators that are in the rooms match those figures is another matter!
They were here when I moved in.

I'll check out the web sites you suggested. Thank you.