On Thu, 22 Jan 2004 01:13:58 -0000, "IMM" wrote:


"Andy Hall" wrote in message
.. .


100W of heating by gas at a price of 1.4p per kWh works out to just
over £12 per annum.

In terms of the material cost, this provides a reasonable rate of
return. However, if you set it in the context of whether the space
is important to you and the cost of the timber and other means to
access it, then this becomes less interesting.

In energy terms, if you compare with the heat loss through the walls
and other means, then you realise that the focus should be on other
issues than this.

How mixed up you are. Overall the walls loose more heat than the upper
ceilingof a house.

Obviously. The area is generally larger and the U value greater or
comparable to 100mm of loft insulation


That is misleading. Then look at the individual rooms
below the loft. They will have a large area which is loft ceiling.

They will have a large area of walls and windows as well.

Then it
makes sense to heavily insulate, as these rooms will be warm in winter and
cool in summer.

That doesn't follow at all.


In August the coolest place in my house was the main
bedroom. No heat came down from the loft above as I have 350mm of
insulation.

That doesn't follow either.

Provide the dimensions of the room including the windows and the
construction type of the walls and windows and we can do the sums.

I would be very surprised if the difference in heat gain that you
experience through having 350mm of insulation vs. 100 or 150mm is
significant in comparison to gains through other surfaces.




A light wind through the two windows and it was fine in the
upper rooms. In winter they are very warm.

And you said a uni made you think?

Yes it does, as well as the ability to spot bull**** when I see it.






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..andy

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