"Andy Hall" wrote in message
...
On Mon, 5 Jan 2004 19:50:40 -0000, "John Stumbles"
] wrote:

I've just done a heatloss calculation for a small terraced house (3.8m
wide
x 7.4m deep x 2.4m each storey with 2.5m x 4m back addition, mix of
carpeted
wooden and solid floors, mostly single glazed, 50mm insulation in the
roof)
and get just over 6.5kW, which seems very low. I've done the calcs on a
spreadsheet but cross-checked with the Myson calculator for the floor and
air changes of one room, to sanity check.

Does this seem right? I could put it all through the Myson to completely
cross-check it but it's a lot of extra work ...

tia

This seems low to me as well.

Presumably this is an older property with solid walls..??

I've assumed 220mm brick + 13mm plaster, U=2.0 (from BS5449 - I see Myson
use a figure of 1.8 for this construction).

I would expect the extension to have a fairly large heat loss because
of the external wall area.

(The extension shares a party wall with next door.)
I make its loss though external walls 712W. (Actually that includes a new 2m
extension to the ground floor at the back, which has insulated cavity
walls.)

How have you treated the party walls?

I've assumed next door temperatures of 15 downstairs, 10 upstairs (more
pessimistic than the usual 18 up and down, I know).

So for example my big main room (through lounge) has a party wall area of 2
(party walls) * 7.4m (width) * 2.4m (height) = 35.52m^2, and therefore a
heat loss of 35.52 * 2.0 (U value) * 6 (21C - 15C temp diff) = 426 Watts



--
John Stumbles
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