Lobster wrote:
John Stumbles wrote:
On Thu, 14 Sep 2006 11:02:50 +0100, HLAH wrote:

"Dave Fawthrop" wrote
Put one twice the size you think would be right, and fit a TRV.
--
That's pretty much our plumbers strategy. It makes sense to me.
Price of steel these days it's better to calculate it and get it right.
Often I've been suprised how small (and sometimes how large) a rad needs
to be for a given room.

TBH I suspect that the cost difference between my largest
"guesstimated" rad wouldn't be vastly different to the ideal size, so
that's not my main motive - would just rather keep it neat and not clog
up the room with more hardware than required.

Anyone know of a Noddy guide to calculating U-values? Once tried doing
it from first principles before, without a software calculator, and
came unstuck!

For the purpose of rad sizing/U-value calcs, does it matter whether the
sloping area is considered as "wall" or "ceiling"?

(BTW floor area is (IIRC) something like 3.5 x 3m (I'm not at home now)
but the flat area of the ceiling is probably half that?)


I cvan tell you instantly by comparison with here, that something
around a kilowatt (3500 BTU/h) will be ample. TRV it of course to make
sure you do not overheat.

I have less good insulation and the one room my 1.2KW isn't quite enough
is about 5x3 meters, north facing, with not much heat coming up from
below as its over a guest area thats not in use often.

I'd say one meter length of double radiator would be ample. Or two
smaller if it fits better aesthetically. I hate radiators..I fitted hot
air blowers instead. Yes they whirr, but a kilowatt is a 18" square
panel in the wall..

Anyway, pick whatever suits from e.g. here

http://www.screwfix.com/app/sfd/cat/...01444&ts=37431



Thanks
David