On Fri, 19 May 2006 20:47:42 GMT someone who may be John Stumbles
wrote this:-

That depends on the situation. For example, if someone was able to
run an old boiler for a few more years and then install a micro CHP
unit I suspect that would be better for the environment.

OK, but that would be an extremely unusual situation

I don't think so.

and, dare I say?, a rather contrived example.

It is an example of a situation I am familiar with in a few places.

I was (and am) trying to establish a rule of thumb that you don't put in
solar water heating before you've addressed draughtproofing, insulation
and heating efficiency.

All these things need to be done, but within limits. These limits
are not precise, but depend on individual priorities.

Certainly insulation of pipes and cylinders is a priority. However,
the best way of insulating a cylinder may be to replace it with a
solar cylinder. If doing so it may make sense to use it properly. I
don'y think there are any hard and fast rules, it is a matter for
the art of engineering.

BTW picking up on your mention of microCHP I looked into the MicroGen and
WhisperGen but they didn't seem to be available at the moment.

They have been installed in a few trial areas IIRC.

There are also issues of what to do with surplus electricity produced

In the UK the electricity output will largely tie up with maximum
demand, for example lighting demand is highest on winter nights when
central heating is also turned on.


--
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