"David WE Roberts" wrote in message
...
In the next couple of years we intend to remodel the back of the house,
put in a downstairs shower and toilet, and do various other things.

This will include replacing the current boiler and doing something with
the hopeless hot water system - at the moment you have to run the water
for a couple of minutes before anything approaching hot water comes
through.

Obvious choice is a combi boiler situated close to the kitchen and
bathroom to give short pipe runs and on demand hot water.

However this is also an opportunity to 'go green' with for example a heat
store, solar water heating on the roof, a wood pellet boiler.
This also gives the option of adding other heat sources such as a solid
fuel stove with back boiler to heat water in the winter.
In this case the pipe runs are likely to be longer but good lagging and a
pump may help the 'instant hot water' requirement.

Is this a feasible option?
It looks expensive compared to a combi boiler - at least three major
components at least compared with one - and the financial (as opposed to
moral) payback may be unrealisitically long.

Has anyone gone down this route?

Is anyone contemplating it?

For us it will be a 'now or never' thing as once the house is done we have
no intention of mucking about with it for some considerable time.

Cheers

Dave R

I've had solar HW installed for 2 years now. It's based on a 30 tube
Navitron panel, and a custom-made conventional (vented system) cylinder with
two coils from a different supplier. (Can't remember who, a company
recommended on here at the time)

Like other posters my boiler rarely runs over the summer, and the solar
system acts as a pre-heat on the HW cylinder over the winter, reducing the
gas used then a little.

According to it's controller, it's stored just over 5500kWh in that time,
which, assuming a 100% efficient boiler would cost £177 in gas costs with my
current supplier. I don't know what the efficiency of the boiler is, but if
I assumed around 60% (cast iron heat exchanger, non-condensing) would equate
to about £250 in saved gas costs - which agrees with the vastly reduced gas
bills. Like another poster I had bills in credit for ages until their system
& direct debit caught up with my reduced consumption.

My total solar cost was about £2k however I was replacing the cylinder with
a custom-made short'n'wide one anyway as part of a CH re-plumb, zone
split-up and airing cupboard move around so the extra cost for a solar coil
was minimal.

So... the payback time financially is long. Very long. If gas prices rise
the time will reduce, but as a money-saving method it's not really worth it.
I'm no tree-hugger and not convinced on the 'saving the planet' aspect
either - obviously there is a 'carbon footprint' in making the solar
equipment in the first place!
Going for a condensing boiler may have a quicker pay-pack time, I've not
done this as the existing one is only 8 years old, has been 100% reliable
and the location is not suitable for a condensing one (flue problems) so
would mean a major re-plumb.

Alan.