Posted by Jonathan on October 14, 2007, 1:12 pm
Mike has somehow managed to knacker OE so it doesn't put the quotes
properly, so I've re-inserted them to avoid confusion....
I've never come across this - unless your loft is of extremely poor or
degraded construction. OR you may have been looking at a combination
of "old-tech" flat panels AND a weak roof.
IF you live in a listed building AND and conservation area OR the
panels need to be bracketed (standing out from the roof) because there
is no convenient south/southwest/southeast facing roof then you MAY
need to check for planning permission. About 1 in 10 installations
needs to check for planning.
For a fully fitted, insured and guaranteed twin panel vacuum tube
system including all parts, labour, insurance, new tank etc, that is
about at the upper limit, yes.
I bet you got your figures from the....uh-oh!
The big problem with the CAT is that it is ALTERNATIVE not MODERN
technology. The last time I looked, they were using inefficient flat
panels from the 70's.
Fortunately, from their website: "Our solar heating display is
currently being renewed". So I can only hope that something a bit more
realistic is being put it.
See above. Tech from the 70's!
If you can make any sort of shadow, you can warm water. On a semi-
overcast winter's day, you can get about 30 degrees of water, meaning
30 degrees less that the boiler has to heat.
Some data on vacuum tube reflector technology
Posted by Eeyore on October 14, 2007, 6:11 pm
Plenty of Victorian era houses wouldn't meet today's building regs.
Posted by Derek Geldard on October 14, 2007, 7:08 pm
On Sun, 14 Oct 2007 19:11:45 +0100, Eeyore
They, *may*, probably, be alright. ;-))
But a modern trussed roof (As opposed to what builders call a "Proper"
roof) is only designed to support the weight and wind loadings of the
roof itself and the ceiling that hangs from it.
Posted by Peter Parry on October 14, 2007, 10:25 pm
Actually the "modern" vacuum tubes being sold at inflated prices
pre-date the 70's by a considerable margin and were in domestic use
in the mid-70's at least. They are not exactly "high tech", their
advantage from an salesman's point of view is they look it and can be
used to fool the gullible. The problem is that in the UK they are
not all that much more effective than the flat panel.
For some unbiased data the DTI report ETSU S/P3?00275/REP/2 DTI/Pub
URN 01/1292 gives the figures for vacuum tube and flat panel systems
which were monitored over 7 months. They found little difference
between the overall system performance of flat panel and evacuated
In general the systems produced 75% or more of the domestic hot water
requirement during May Jun and Jul, between 50 and 75% in Aug and
Sept, Less than 30% in Oct, and about 10% from Nov to Jan rising to
20% in Feb and 40% in Mar. For most people that doesn't produce a
saving of £75 per year much less "many times more".
Indeed your favoured Energy Saving Trust in their report "Potential
for Microgeneration Study and Analysis Final Report 14th November
"[Solar water heating is] Currently the largest microgeneration
industry, installing 2000 units annually. Generally, solar water
heating is not cost effective at present. The technology is most
effective if replacing electric heating systems."
"Solar water heating (active solar): reductions in generated energy
cost are required for break even with electrical water heating.
Break-even is not predicted for gas (or oil) boiler water heating.
This is because of high capital costs combined with low oil and gas
prices. Approximately 50% capital cost reduction is necessary for
break-even with electrical water heating by 2015 2020."
"Solar water heating does not break-even with gas boiler water
heating, and will require large cost reductions to break-even with
electrical water heating by 2015 2020."
Posted by Jonathan on October 14, 2007, 11:02 pm
Wow..someone doesn't pay the bills in their household :)
Yup, those low oil prices are the bane of my life....17p to 37.5p per
litre in 3 years. They're just giving it away, right?
As the OPEC report for Friday 6th July 2007 says:
"The OPEC Reference Basket, the main benchmark for crude oil prices,
reported a rise from $8.47/barrel, on average for March, to $6.77/
barrel by the close of June. There are a number of short-term factors
which have impacted upon and augmented the long-term underlying trend
of rising oil prices, caused by world demand outstripping supply."
And it's only going to get cheaper, and what with the rising cost of
the sun.....are we actually having a sensible discussion here, or are
people just going to keep throwing out of date figures around?