Has anyone here had domestic solar water heating installed? I know this is
the DIY group but I'm looking for someone to do it for me. Googling has
produced a number of companies and trade associations but there's nothing
like a personal recommendation (or warning).

I'm on the Somerset/Wiltshire border (some companies only seem to work in
certain parts of the country).

Thank you.

Graham Harrison wrote:
Has anyone here had domestic solar water heating installed? I know this is
the DIY group but I'm looking for someone to do it for me. Googling has
produced a number of companies and trade associations but there's nothing
like a personal recommendation (or warning).

I'm on the Somerset/Wiltshire border (some companies only seem to work in
certain parts of the country).

Thank you.

Commercial solar HW systems are a great way to throw your money away.
Suggest looking at solar flat plate space heating, less cost, more heat
gain. Try alt.solar.thermal for info & expertise.

NT

wrote in message
ups.com...
Graham Harrison wrote:
Has anyone here had domestic solar water heating installed? I know this
is
the DIY group but I'm looking for someone to do it for me. Googling has
produced a number of companies and trade associations but there's nothing
like a personal recommendation (or warning).

I'm on the Somerset/Wiltshire border (some companies only seem to work in
certain parts of the country).

Thank you.

Commercial solar HW systems are a great way to throw your money away.
Suggest looking at solar flat plate space heating, less cost, more heat
gain. Try alt.solar.thermal for info & expertise.

NT


Looks like I've got quite a lot of research to do. Thanks.

On 22 Nov 2005 14:54:03 -0800 someone who may be
wrote this:-

Commercial solar HW systems are a great way to throw your money away.

They are certainly not going to have a short payback period.
However, the same is true of double glazing. There are plenty of
other reasons for installing solar hot water systems than payback
period.

Suggest looking at solar flat plate space heating, less cost, more heat
gain.

Far more expensive if one is going to produce enough heat for a
house. A major problem is that the heat is available in the summer,
but needed in the winter. It might make a contribution in spring and
autumn, when there are relatively sunny days and cold nights. Such
heating is ideal in warm places with cold nights, such as deserts.


I suggest the original poster looks at two companies:

1) if they have no requirement for extra water storage and their
existing cylinder is well lagged. www.solartwin.com which involves
less work.

2) if they want extra water storage or their existing cylinder is
not well lagged. http://www.imaginationsolar.com/ which involves
more work but produces a better result.

Both avoid mains powered pumps, which has many advantages.



--
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

David Hansen wrote:
On 22 Nov 2005 14:54:03 -0800 someone who may be
wrote this:-

Commercial solar HW systems are a great way to throw your money away.

They are certainly not going to have a short payback period.
However, the same is true of double glazing. There are plenty of
other reasons for installing solar hot water systems than payback
period.

Suggest looking at solar flat plate space heating, less cost, more heat
gain.

Far more expensive if one is going to produce enough heat for a
house.

far cheaper in fact. They do not produce all the heat for a house, but
a substantial percentage. Far more than a commercial DHW panel ever
would.


A major problem is that the heat is available in the summer,
but needed in the winter.

heat is available in winter too, and it is this level the system is
designed for.


I suggest the original poster looks at two companies:

Both avoid mains powered pumps, which has many advantages.

it makes payback even poorer.


NT

"David Hansen" wrote in message
...
On 22 Nov 2005 14:54:03 -0800 someone who may be
wrote this:-

Commercial solar HW systems are a great way to throw your money away.

They are certainly not going to have a short payback period.
However, the same is true of double glazing. There are plenty of
other reasons for installing solar hot water systems than payback
period.

Suggest looking at solar flat plate space heating, less cost, more heat
gain.

Far more expensive if one is going to produce enough heat for a
house. A major problem is that the heat is available in the summer,
but needed in the winter. It might make a contribution in spring and
autumn, when there are relatively sunny days and cold nights. Such
heating is ideal in warm places with cold nights, such as deserts.

Try the Thermomax panels from Navitron - I gave the link. An array of those
and a large thermal store supplying very low temp UFH and it may be viable.

The UK has about half the sun of north America in winter. The most cost
effective way to save energy is:

1. Insulate as much as possible: cavity wall, 1 foot in the loft, foam
against the side of the foundations (easy to do, just digging).

2. Make the house as air-tight as possible: spay-in Warcell in the loft,
sealed triple glazing and doors, ect. Seal up chimney breast.

Then use solar as DHW only.

On Wed, 23 Nov 2005 18:29:53 -0000, "Doctor Drivel"
wrote:

Try the Thermomax panels from Navitron - I gave the link.

Oddly enough, I find myself almost agreeing with Drivel. I've no idea
who Navitron are, but Thermomax make a good product. If they can get
them to work cost-effectively in Northern Ireland, they ought to work in
Somerset!

Doctor Drivel wrote:

Try the Thermomax panels from Navitron - I gave the link. An array of those
and a large thermal store supplying very low temp UFH and it may be viable.

The UK has about half the sun of north America in winter. The most cost
effective way to save energy is:

1. Insulate as much as possible: cavity wall, 1 foot in the loft, foam
against the side of the foundations (easy to do, just digging).

2. Make the house as air-tight as possible: spay-in Warcell in the loft,
sealed triple glazing and doors, ect. Seal up chimney breast.

Then use solar as DHW only.

Tell us something. Why install an array of highly priced commercial
panels/tubes, plus plumbing system, plus UFH, when you could just as
well install panels that are nothing more than glazed frames with black
cloth, add holes in the wall and dampers, and harvest stacks of heat
directly without all that nonsense in the way. You'd get twice the
output for half the money.

Re storage, you dont use any. Theres a temperature comfort range, the
day time heating takes it to however high your comfortable with, and
temp drops very slowly in the evening. If it drops to the lower end of
your chosen range, the CH tops up.


NT

wrote in message
oups.com...
Doctor Drivel wrote:

Try the Thermomax panels from Navitron - I gave the link. An array of
those
and a large thermal store supplying very low temp UFH and it may be
viable.

The UK has about half the sun of north America in winter. The most cost
effective way to save energy is:

1. Insulate as much as possible: cavity wall, 1 foot in the loft, foam
against the side of the foundations (easy to do, just digging).

2. Make the house as air-tight as possible: spay-in Warcell in the
loft,
sealed triple glazing and doors, ect. Seal up chimney breast.

Then use solar as DHW only.

Tell us something. Why install an array of highly priced commercial
panels/tubes, plus plumbing system, plus UFH, when you could just as
well install panels that are nothing more than glazed frames with black
cloth, add holes in the wall and dampers, and harvest stacks of heat
directly without all that nonsense in the way. You'd get twice the
output for half the money.

You are on about an air heater in a conservatory. Good choice and v good.
But you need a conservatory.

Re storage, you dont use any. Theres a temperature comfort range, the
day time heating takes it to however high your comfortable with, and
temp drops very slowly in the evening. If it drops to the lower end of
your chosen range, the CH tops up.

The Navitron Thermomax panels are cheap and will produce heat when the flat
plates will not.

On 23 Nov 2005 17:32:26 -0800, wrote:

Why install an array of highly priced commercial
panels/tubes, [...]

Because a passive system really needs to be designed into the building
when it's built (or extended).

Because a flat panel system works well in wam weather but very badly in
cold sunny weather. It may still capture plenty of solar heat, but it
also has losses too high for effective use in our climate, year-round.

wrote in message
ups.com...
Graham Harrison wrote:
Has anyone here had domestic solar water heating installed? I know
this is
the DIY group but I'm looking for someone to do it for me. Googling
has
produced a number of companies and trade associations but there's
nothing
like a personal recommendation (or warning).

I'm on the Somerset/Wiltshire border (some companies only seem to work
in
certain parts of the country).

Thank you.

Commercial solar HW systems are a great way to throw your money away.
Suggest looking at solar flat plate space heating, less cost, more heat
gain. Try alt.solar.thermal for info & expertise.

It is best to look here as the prices are highly competitive:
http://www.navitron.org.uk/

On Tue, 22 Nov 2005 20:59:43 +0000 (UTC), "Graham Harrison"
wrote:

Has anyone here had domestic solar water heating installed?

My parents house had it (self install - DIY cost about GBP500 in
total using some very expensive glass vacuum collectors found in a
scrap yard - it was finding the collectors which caused the thing to
be built!) and a neighbour later had a commercial one fitted. Over
20 years neither broke even or got remotely near doing so. Both
houses had virtually ideal south facing roofs of appropriate pitch.

Two reports worth looking at are

http://www.broadband.gov.uk/energy/r.../sp300275r.pdf

and

http://www.dti.gov.uk/renewables/pub...load=01%2F1292

These do at least put some figures on the likely effects of these
units (something the manufacturers studiously avoid doing).

From those tests the amount of energy from the panels tested came to
roughly in the range 3,400 to 4,800 MJ per year. 1kw/hr (1 unit of
electricity) = 3.6 MJ so that is between 945 and 1,330 kw/hr per year
in ideal locations. If they are not south facing and at the right
angle that figure can reduce by 50%.

Assuming 1,100 kw/hr is contributed per year the equivalent fuel
costs are roughly:-

Gas (2p per kW/hr) = GBP22
Electricity (9p peak rate) = GBP99
Electricity (3p off peak rate) = GBP33

(These figures do not include any standing charge)

The saving achieved by using solar water heating in ideal situations
is therefore in the order of only GBP22 to GBP100 per annum.

As the installed cost of commercially fitted solar panels is in the
region of GBP3,000 to GBP5,000 or more it is not surprise that the
manufacturers so carefully avoid any mention of how much energy the
things actually (don't) produce and the fact they can never pay for
themselves as the payback period is considerably greater than the
system life.



--
Peter Parry.
http://www.wpp.ltd.uk/

On Wed, 23 Nov 2005 12:41:15 +0000 someone who may be Peter Parry
wrote this:-

These do at least put some figures on the likely effects of these
units (something the manufacturers studiously avoid doing).

Incorrect.

Solartwin make quite a lot of one of the reports you mentioned.

http://www.solartwin.com/questions_a...s.htm#evidence

"Where's the evidence of this 20%?

"A recent UK government-funded study of eight solar water heating
systems at Milton Keynes confirmed what has long been suspected:
that the environmental benefits of solar can be substantially
improved by eliminating mains electricity. ( Side by side testing of
eight solar water heating systems 2001 DTI/Pub URN 01/1292)

"In this study, flat plate solar hot water systems negated an
average of 17% of their potential global warming benefits (i.e. CO2
savings) by using mains electricity.

"For partial-vacuum tubes ("solar tubes"), their loss averaged even
higher, at 23%.

"In other words, if you run mains-powered solar for ten years, its
electricity consumption deletes its CO2 saving by about two years.

"Solartwin’s environment-centred solar water heating design brief
specifies a solar electric pump. So your CO2 savings won’t retreat
two steps after advancing ten."

As the installed cost of commercially fitted solar panels is in the
region of GBP3,000 to GBP5,000 or more it is not surprise that the
manufacturers so carefully avoid any mention of how much energy the
things actually (don't) produce and the fact they can never pay for
themselves as the payback period is considerably greater than the
system life.

Solar water heating is much like double glazing. If you do it just
to save money then you are not going to do very well out of it.
However, if you do it for a whole range of other reasons then the
investment makes perfect sense.




--
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

David Hansen wrote:
On Wed, 23 Nov 2005 12:41:15 +0000 someone who may be Peter Parry
wrote this:-

"A recent UK government-funded study of eight solar water heating
systems at Milton Keynes confirmed what has long been suspected:
that the environmental benefits of solar can be substantially
improved by eliminating mains electricity. ( Side by side testing of
eight solar water heating systems 2001 DTI/Pub URN 01/1292)

"In this study, flat plate solar hot water systems negated an
average of 17% of their potential global warming benefits (i.e. CO2
savings) by using mains electricity.

"For partial-vacuum tubes ("solar tubes"), their loss averaged even
higher, at 23%.

"In other words, if you run mains-powered solar for ten years, its
electricity consumption deletes its CO2 saving by about two years.

It would take a not especially well designed system to waste 17% or 23%
on electricity. What you dont mention here is that using a solar panel
to provide power means more embodied energy used in manufacturing the
thing, plus more cost to pay back.


"Solartwin's environment-centred solar water heating design brief
specifies a solar electric pump. So your CO2 savings won't retreat
two steps after advancing ten."

no, but you start from a position further back, due to embodied energy
in the panel. Youre also further back financially.


Solar water heating is much like double glazing. If you do it just
to save money then you are not going to do very well out of it.

correct

However, if you do it for a whole range of other reasons then the
investment makes perfect sense.

it doesnt, for one simple reason: you can spend less, invest less
embodied energy, and receive greater returns with solar space heating.


NT

On Wed, 23 Nov 2005 15:05:37 +0000, David Hansen
wrote:

On Wed, 23 Nov 2005 12:41:15 +0000 someone who may be Peter Parry
wrote this:-

These do at least put some figures on the likely effects of these
units (something the manufacturers studiously avoid doing).

Incorrect.

Solartwin make quite a lot of one of the reports you mentioned.

Indeed they do - most misleadingly. As with all other manufacturers
they also, as I stated, avoid real figures like the plague and have
no link to download the report they quote. Instead there is a
rambling missive about vague greenery and a wholly ridiculous claim
that the value of your house will go up by at least GBP1,000 and your
boiler get two years of extra life.

http://www.solartwin.com/questions_a...s.htm#evidence

"Where's the evidence of this 20%?

20% of what? They present it as if it is a huge saving, in fact the
performance of their product is pretty middle of the road in a bunch
which collectively are dire.

"In this study, flat plate solar hot water systems negated an
average of 17% of their potential global warming benefits (i.e. CO2
savings) by using mains electricity.

Which fails to mention that the benefits are minimal to begin with -
17% of 2/3 square root of sod all is still sod all.

"For partial-vacuum tubes ("solar tubes"), their loss averaged even
higher, at 23%.

The loss was exactly the same - this is simple dishonest use of
percentages to make a marketing point.

Solar water heating is much like double glazing. If you do it just
to save money then you are not going to do very well out of it.
However, if you do it for a whole range of other reasons then the
investment makes perfect sense.

It is nothing like double glazing. Double glazing brings with it a
number of other advantages such as better noise insulation, less
condensation and improved comfort within rooms by eliminating
draughts. Solar water heating has no advantages at all over any
other form of water heating, however, as well as making no economic
sense is visually unattractive and also a very unreliable heating
source.

Solar water heating will never make sense in the vast majority of
situations in the UK.



--
Peter Parry.
http://www.wpp.ltd.uk/

"Peter Parry" wrote in message
...
On Wed, 23 Nov 2005 15:05:37 +0000, David Hansen
wrote:

On Wed, 23 Nov 2005 12:41:15 +0000 someone who may be Peter Parry
wrote this:-

These do at least put some figures on the likely effects of these
units (something the manufacturers studiously avoid doing).

Incorrect.

Solartwin make quite a lot of one of the reports you mentioned.

Indeed they do - most misleadingly. As with all other manufacturers
they also, as I stated, avoid real figures like the plague and have
no link to download the report they quote. Instead there is a
rambling missive about vague greenery and a wholly ridiculous claim
that the value of your house will go up by at least GBP1,000 and your
boiler get two years of extra life.

http://www.solartwin.com/questions_a...s.htm#evidence

"Where's the evidence of this 20%?

20% of what? They present it as if it is a huge saving, in fact the
performance of their product is pretty middle of the road in a bunch
which collectively are dire.

"In this study, flat plate solar hot water systems negated an
average of 17% of their potential global warming benefits (i.e. CO2
savings) by using mains electricity.

Which fails to mention that the benefits are minimal to begin with -
17% of 2/3 square root of sod all is still sod all.

"For partial-vacuum tubes ("solar tubes"), their loss averaged even
higher, at 23%.

The loss was exactly the same - this is simple dishonest use of
percentages to make a marketing point.

Solar water heating is much like double glazing. If you do it just
to save money then you are not going to do very well out of it.
However, if you do it for a whole range of other reasons then the
investment makes perfect sense.

It is nothing like double glazing. Double glazing brings with it a
number of other advantages such as better noise insulation, less
condensation and improved comfort within rooms by eliminating
draughts. Solar water heating has no advantages at all over any
other form of water heating, however, as well as making no economic
sense is visually unattractive and also a very unreliable heating
source.

Solar water heating will never make sense in the vast majority of
situations in the UK.

It will if it is designed and built into new homes, renovations and
extensions. If it is made mandatory the capital cost will plummet and it
will be viable.

Dramatic price reduction is the one barrier with SDHW, and one thats
addressable in the years ahead imho.

Mass produced freezeproof moulded panels can be fitted into the roof so
that they replace an area of tiling, thus cutting their effective cost
for new builds.
Add suitable control as part of some standard CH controllers and the
control costs drop.
Instead of one collector per house, install a large bank of panelling
on flats to supply a communal HW source, and the paperwork and
organisation costs per flat drop, and diversity kicks in, ensuring
quick recovery.
Include a set of minimum cost unglazed panels for prewarming cold
incoming water.

Etc.

If solar cost 1/4 the price it would be worth it today. Energy costs
are on the up, and there are many ways to cut solar costs once it gets
out of the gimmick league. Also manufactured goods costs are coming
down every decade. I reckon they might well become widespread in time.


NT

On Wed, 23 Nov 2005 18:01:06 +0000 someone who may be Peter Parry
wrote this:-

It is nothing like double glazing. Double glazing brings with it a
number of other advantages

Something I said in my posting.

Solar water heating has no advantages at all over any
other form of water heating,

Really. So not burning gas or electricity and thus reducing
greenhouse gas emissions is not an advantage? Not running a boiler
all the year round is not an advantage? Fascinating.

as well as making no economic
sense is visually unattractive

I suspect we are getting to your real motives now. Do you think that
a panel built into a roof www.imaginationsolar.com is unattractive?

and also a very unreliable heating source.

Owners of modern systems seem happy with them, perhaps you are
thinking of some of the earlier systems (still sold, sadly) with
pre-heating cylinders and the like.

Solar water heating will never make sense in the vast majority of
situations in the UK.

As others have said, mass production and installation in new
buildings will even change the economics. Meanwhile the other
advantages remain.

Perhaps you would like to study the recent report on sustainable
heating systems by the Sustainable Development Commission. This
gives the best view on the subject recently.

--
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

On Thu, 24 Nov 2005 05:12:38 +0000, David Hansen
wrote:

On Wed, 23 Nov 2005 18:01:06 +0000 someone who may be Peter Parry
wrote this:-

Solar water heating has no advantages at all over any
other form of water heating,

Really. So not burning gas or electricity and thus reducing
greenhouse gas emissions is not an advantage?

No, because it is trivially insignificant. If every house in the UK
went to solar water heating tomorrow it would have a negligible
effect upon world greenhouse gas emissions. Indulging in posture
politics and switching off brain as soon as "global warming" is
mentioned simply distracts from the real problem which isn't in the
UK or capable of being solved by the UK.

Not running a boiler all the year round is not an advantage?

No, because the solar supply is unreliable - you still need
conventional water heating available. If you switch off the boiler
for the summer and rely upon a daytime immersion heater for the times
the solar water heating is inadequate the small saving it makes is
wiped out in a few days.

as well as making no economic sense is visually unattractive

I suspect we are getting to your real motives now.

Try not to be a prat all your life.

Do you think that
a panel built into a roof www.imaginationsolar.com is unattractive?

Actually, yes, nearly all the examples shown are pretty awful. Not
all roofs are dull grey.

Solar water heating will never make sense in the vast majority of
situations in the UK.

As others have said, mass production and installation in new
buildings will even change the economics.

Possibly, but we are talking about retrofitting today - not built in
tomorrow.


--
Peter Parry.
http://www.wpp.ltd.uk/

"Peter Parry" wrote in message
...
On Tue, 22 Nov 2005 20:59:43 +0000 (UTC), "Graham Harrison"
wrote:

Has anyone here had domestic solar water heating installed?

My parents house had it (self install - DIY cost about GBP500 in
total using some very expensive glass vacuum collectors found in a
scrap yard - it was finding the collectors which caused the thing to
be built!) and a neighbour later had a commercial one fitted. Over
20 years neither broke even or got remotely near doing so. Both
houses had virtually ideal south facing roofs of appropriate pitch.

Two reports worth looking at are


http://www.broadband.gov.uk/energy/r...s/sp300275r.pd
f

and


http://www.dti.gov.uk/renewables/pub...pdf?pubpdfdloa
d=01%2F1292

These do at least put some figures on the likely effects of these
units (something the manufacturers studiously avoid doing).

As energy has taken a price hype, the figures may be rather out of date.
These 20 year old systems may start to pay for themselves big-time.

"Peter Parry" wrote in message
...
On Tue, 22 Nov 2005 20:59:43 +0000 (UTC), "Graham Harrison"
wrote:

Has anyone here had domestic solar water heating installed?

My parents house had it (self install - DIY cost about GBP500 in
total using some very expensive glass vacuum collectors found in a
scrap yard - it was finding the collectors which caused the thing to
be built!) and a neighbour later had a commercial one fitted. Over
20 years neither broke even or got remotely near doing so. Both
houses had virtually ideal south facing roofs of appropriate pitch.

I don't believe it. If you spent £500 20 years ago and you haven't recouped
the cost? Do some sums. That is £25 a year. A DHW solar setup will save
more than £25 in energy costs a year, unless they don't use much DHW at all.

In article ews.net,
Doctor Drivel wrote:
I don't believe it. If you spent £500 20 years ago and you haven't
recouped the cost? Do some sums. That is £25 a year.

'Sums' is all it is - like a five year old could do. An adult brain would
consider things like interest.

500 quid invested 20 years ago could have given a return of far more that
25 quid a year in the early years.

Get your nurse to explain it to you when she gives you your medication
before putting you outside in your bathchair. And make sure she gives you
an extra blanket.

--
*Ham and Eggs: Just a day's work for a chicken, but a lifetime commitment

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:

I don't believe it. If you spent £500 20 years ago and you haven't
recouped the cost? Do some sums. That is £25 a year.

'Sums' is all it is

Yes he knows sums. Probably into take-ways by now.

*** snip senility **

On Thu, 24 Nov 2005 09:07:39 -0000, "Doctor Dribble"
wrote:



I don't believe it.

I'm sure you don't. Elementary understanding of physics and maths
has always been rather beyond your meager abilities.

If you spent £500 20 years ago and you haven't recouped
the cost? Do some sums.

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.




--
Peter Parry.
http://www.wpp.ltd.uk/

"Peter Parry" plehead extrodanaire wrote in message
...

I don't believe it.

I'm sure you don't. Elementary understanding of physics and maths
has always been rather beyond your meager abilities.

If you spent £500 20 years ago and you haven't recouped
the cost? Do some sums.

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

£18 a year? It must be facing north, or poorly and inefficiently
installed - must be if you had anything to do with it.

On Thu, 24 Nov 2005 11:42:35 -0000, "Doctor Dribble"
wrote:


£18 a year? It must be facing north, or poorly and inefficiently
installed - must be if you had anything to do with it.

OK, I'll give you clue as it is unlikely you would ever work it out
and yet again you demonstrate your inability to read. The rest of
the heating system was very efficient. As it was efficient the cost
of heating water was low and the saving from the solar water heating
was therefore also low. The amount of energy available for the
solar panels to collect is unalterable. If they had been 100%
effective they would still have been a poor investment.

--
Peter Parry.
http://www.wpp.ltd.uk/

On Thu, 24 Nov 2005 11:28:16 +0000, Peter Parry
wrote:

On Thu, 24 Nov 2005 09:07:39 -0000, "Doctor Dribble"
wrote:



I don't believe it.

I'm sure you don't. Elementary understanding of physics and maths
has always been rather beyond your meager abilities.

If you spent £500 20 years ago and you haven't recouped
the cost? Do some sums.

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

What's the cost of energy (per kWh) that the £18/yr saving is based
upon? If based upon natural gas that could help explain why the
returns from the solar system are quite low.

Also how many people in your parents household? If only 2 it's
possible the system is oversized for their needs and they can't use
the majority of the water heated by the system.

For a four person household heating with LPG or oil where the system
can be DIY installed I'd expect the economics are quite different.

I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

cheers,
Pete.

On Thu, 24 Nov 2005 16:23:27 +0000, Pete C
wrote:

On Thu, 24 Nov 2005 11:28:16 +0000, Peter Parry
wrote:

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

What's the cost of energy (per kWh) that the £18/yr saving is based
upon?

The actual cost of fuel each quarter over the decade or so the system
was monitored.

If based upon natural gas that could help explain why the
returns from the solar system are quite low.

It was natural gas, and an efficient and carefully sized boiler.

Also how many people in your parents household? If only 2 it's
possible the system is oversized for their needs and they can't use
the majority of the water heated by the system.

It varied between two and four over the period. There were certainly
a few times in the summer months with only two people that more hot
water was produced than could be used.

For a four person household heating with LPG or oil where the system
can be DIY installed I'd expect the economics are quite different.

I don't think many people could install a better system for lower
cost - remember the starting point was the purely serendipitous
discovery of a stack of apparently new vacuum tube solar collectors
in a scrap yard which avoided the major cost and the construction was
entirely DIY.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

The life of solar panels isn't infinite, nor are they a practical
energy saving measure in most situations.

--
Peter Parry.
http://www.wpp.ltd.uk/

Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Hi Graham,

I have looked extensively at solar water heating. I could bore you to
death with figures and calculations but my opinion is that at todays
prices you will never see payback on a commercially installed system.
I have looked at DIYing it and worked out a payback of 20 years (not
counting running and maintenance costs) and that is comparing it to oil
which is comparatively expensive.
As a commercialy installedl system (even with a grant) is much more
expensive than DIY then your payback time is even greater than that.
I should also mention I am in central Scotland so I guess you might
have more sun than me and perhaps a better payback...

As energy prices increase, the payback time gets better so my advice to
you is to revisit this in a few years.

You didn't mention your motivation for looking at this. If
environmental then it maybe makes sense but I don't know the energy
costs in the manufacture of these.

You also didn't mention how many people you are looking to heat water
for or if this is a retrofit or part of a new build. Payback is better
on a larger system and installation cheaper on a new build.

Alan.

"Alan" wrote in message
ups.com...
Hi Graham,

I have looked extensively at solar water heating. I could bore you to
death with figures and calculations but my opinion is that at todays
prices you will never see payback on a commercially installed system.
I have looked at DIYing it and worked out a payback of 20 years (not
counting running and maintenance costs) and that is comparing it to oil
which is comparatively expensive.

How about using cheap Navitron equipment. They have dropped the price of
Solar equipment like a stone.

As a commercialy installedl system (even with a grant) is much more
expensive than DIY then your payback time is even greater than that.
I should also mention I am in central Scotland so I guess you might
have more sun than me and perhaps a better payback...

As energy prices increase, the payback time gets better so my advice to
you is to revisit this in a few years.

You didn't mention your motivation for looking at this. If
environmental then it maybe makes sense but I don't know the energy
costs in the manufacture of these.

You also didn't mention how many people you are looking to heat water
for or if this is a retrofit or part of a new build. Payback is better
on a larger system and installation cheaper on a new build.

Alan.

Yes, Navitron prices make it at least close to practical but it is
still expensive. I'd love to know how good they are - how can Navitron
be so cheap? Is there a catch?
Anyway, my calculations are done using Navitron pricing -
£395 for the collector + £100 delivery then £200 for a dual coil
cylinder then a controller, temp sensors, pipes, pump etc you are
looking at the best part of a grand for the bits.
I recon I can save £50/year with SDHW which is where I get the 20 year
payback without including maintenance costs.
Yes, spiraling fuel costs will reduce this and I am sure I could save
some of the costs for instance by using a solar panel to drive the pump
- no need for the diff controller/sensors or even by making my own
controller.
Any commercially installed systems I have seen are twice this price
although maybe using Navitron panels will reduce this but even with a
grant this will still be more expensive so not a short term
proposition. It is criminal that grants are not available to DIY'ers.
There should be a law against DIY-ism.

On 30 Nov 2005 05:40:02 -0800 someone who may be "Alan"
wrote this:-

Any commercially installed systems I have seen are twice this price

ISTM that the premium for such systems is £1000. Against this is a
grant and reduction in VAT.

It is criminal that grants are not available to DIY'ers.

I entirely agree, as well as the discrimination over VAT. I think
this is another example of the administrators taking over and
driving out those who know what they are talking about. All very
much "New" Labour claptrap.


--
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

David Hansen wrote:
On 30 Nov 2005 05:40:02 -0800 someone who may be "Alan"
wrote this:-

Any commercially installed systems I have seen are twice this price

ISTM that the premium for such systems is £1000. Against this is a
grant and reduction in VAT.

It is criminal that grants are not available to DIY'ers.

I entirely agree, as well as the discrimination over VAT. I think
this is another example of the administrators taking over and
driving out those who know what they are talking about. All very
much "New" Labour claptrap.

We live in a society where commercial solar DHW installers either dont
know what theyre doing, or dont care, or both, where Administratum
doesnt either, but naively assumes the pros are clueful and gainful,
and the DIYers not to be trusted with a barge pole.

IOW we live in a society where the lie becomes the truth, and the truth
the lie.

Unfortunately society pays the price over and over for this
foolishness.


NT