On 26/04/2012 11:42, The Natural Philosopher wrote:
Michael Kilpatrick wrote:
On 26/04/2012 01:32, The Natural Philosopher wrote:
Michael Kilpatrick wrote:
On 25/04/2012 22:26, John Rumm wrote:

Also don't ignore the possibility of using one combi to heat a
cylinder
of water as well as being able to provide hot water on demand itself.

This is exactly what I specified for our extension, and was surprised
when the plumber said that it was a little unusual.

the cost of a combi and tank exceeds the cost of a system boiler and
tank really so its a waste of money with no advantages

The tank is twin-coil - we have solar thermal fitted.

And that is relevant how?


Because we get lots of nearly-free hot water when the sun shines, the
kitchen/ulitity room/washing machine get on-demand hot water from the
boiler with the absolute minimum water waste owing to proximity to the
boiler, and we get a shower in the master en-suite likewise with the
absolute minimum water waste, owing to proximity of the shower to the
cylinder. Our gas bill has shrunk enormously. It shrunk a fair bit when
the new boiler was put in, and shrunk *massively* a year later when the
solar thermal was eventually installed. Why would I care if a combi
boiler costs more than a system boiler? It is of absolutel no
consequence to me given the gains I have achieved.

(Other than demonstrating value for money is not a concept you are
familiar with).

Tosh. The marginal cost of the twin-coil cylinder was irrelevant as the
whole central heating was replumbed, the old boiler had to be removed
and the hot cylinder needed to be moved and improved, as part of the
extension plans. Not only that, but as we installed solar PV at the same
time as the solar thermal (a year after the extension, with the
twin-coil tank ready and waiting), the scaffolding and installation
costs were all more efficiently utilised. Not only that, we took the
oportunity to undertake a rebuild of the chimney (living room fireplace)
which were getting very near to essential, thus eliminating the need for
scaffolding again at a future date.

Besides that, you appear to be working on the assumption that value for
money is the sole concern. Perhaps it hadn't occurred to you that
someone who can afford to save water might feel that it's worth paying
more for if it did turn out to be more expensive. Rather like the six
cubic metres of water in the rain harvester tank under the patio, which
waters the garden, fills the ponds and flushes all the toilets in the
house. Unlike the boiler, solar etc, I don't really know whether the
rain harvester will ever pay for itself - it was quite expensive to
install - but then, I can throw water around the garden to my heart's
content when everybody else is scowling under a hosepip ban. Hah!

Michael