On 10 Dec, 12:31, David Hansen
wrote:
On Sun, 09 Dec 2007 22:57:02 +0000 someone who may be John Rumm
wrote this:-

Why on Earth are people so antagonistic towards something of which they have
no personal experience?

Why do you assume questions are antagonistic?

Some of the people concerned have given this impression many times
in the past.

Some people may genuinely
want to know if a similar system would be worthwhile for them.

The answer to that question has not changed since the last time it
was discussed. Although I'm not noted for spoon feeding I will make
an exception for once.

There is a question of how one measures things. Some people will
spend 10,000 pounds on a new kitchen, for which they will get a
financial return of nothing, for various reasons which they think
are important to them. Some people will install double glazing,
knowing that it has a number of advantages but saving lots of money
on heating bills is not one of these advantages.

In the case of solar water heating people install it for a variety
of reasons they find acceptable, reducing carbon footprint being an
example.

To generalise, in terms of just pound notes, at current fuel prices,
a "professionally" installed system is unlikely to pay for itself
over anything but the long term, possibly longer than it will last.
At current fuel prices a DIY system, using new components, is likely
to pay for itself over the medium term, say 10 years. As a result
one should always do simple energy saving measures, like insulation,
first and only progress to things like solar water heating after
that.

--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

I think you are being a bit generous with your payback times.
Insolation in middle England is about 0.1kW/m2 on average. A DIY solar
install is going to cost around 500 quid/m2, it's going to be at best
50% efficient. If you think 5p/kWh is a fair price, that means over 20
years to pay for itself. There's no way the system will last that
long, particularly if you use Navitron roof mounts.

T