Solar panels and combi boiler - feasible?

Cardew

Skiduck wrote:

Be aware that Cardew believes in half facts.
None of this is nonsense - I have explained to you before, "double glazing" sales tecniques and the rogue traders selling these systems for 7-9 thousand pounds is deplorable. DO NOT think these people are the same as heating engineers, architects, surveyors and industry professionals.
We have no desire to sell a system to anyone that would not benefit from it or (like one of the rogue traders) sell it to an 89 year old gentleman.
I would think carefully before questioning my scruples next time.

If you looked at those sitges - 1 is not commercial and the other one gives you information about payback which is not too far off the mark, a bit flowered up, but no way inconceievable.

BTW - I have no wish to advertise on this site and have never given out my company name.
We are plumbing and heating engineers, not solar panel salesman.

Once again, half facts Cardew.

My doctor gave me some advice the other day, he said I should quit smoking, but he has a vested interest in peddling his nonsense, so I will ignore it.

You have insidiously promoted the solar industry in this forum with vague unsupported statements.

My position is quite clear:

I have seen absolutely no proof that any form of alternative energy – solar or wind – is an economic proposition – and this is a money saving site.

There are a large number of firms in the alternative energy industry that are cowboys and many of them depend on playing the Green Card. Any firm worth its salt would be able to give a prospective customer written guarantees that the system would produce xxx kWh per year and give current and projected savings; taking into account the cost of borrowing the capital.

If the systems were viable the Government would endorse them as an economic proposition. I have not seen a single independent organisation that states they will save money.


You made a statement that a £6,000 'investment' (I use the term with extreme caution) will be paid back in 15 years. All you have to do is explain how. Some simple figures and assumptions will so.

I willl give you one fact to start with. To borrow £6,000 @ 5%(if you can get it that low) will cost you £300 per annum.

You know full well that you cannot support your statement - or if you can just prove me wrong.

Skiduck

I've given you the information, if you choose to promote the negatives and ignore the positives, that is not my problem. The way you see it is blinkered, there is plenty of information I have given you and there is more out there.
If you are unhappy with my information, speak to independent sources like the Carbon Trust and energy consultants.
interest on an account - debit or credit is exact, I grant you that, however the price increase in fuel predicted by experts is far more that what you percieve it is.

I think Cardew, you have misunderstood my intentions on this site from the start and you will have to accept that I am not here to promote my business in any way shape or form. We do not live on selling solar panels, we are plumbing and heating engineers, you are well aware of the cowboys in the solar industry and I am with you in your grievence against them. However, people on here are asking the questions, I am merely giving them the information given to me by my own investigations, my training in the industry, independent experts and the industry itself.

The person on here that bought solar heating for £6000 was charged a lot more than they should have been, people should be aware £3500 is the max for an average system.

If you have a problem with myself, please keep this out of a money saving forum, I am not here to sell you or anyone else solar panels.

paul_h

This old chestnut again...:rolleyes:

This issue does tend to produce very polarised views, but as a solar DHW system owner and user myself, I can say that Cardew isn't far off the the mark. There is no way an installed solar DHW will ever pay for itself before its useful life is up - usually quoted at around 20 years.

I have 5 square metres of solar DHW panels which I inherited when I purchased the house. It produces around half of out annual DHW requirement, which I would say saves us about £60 per annum - that's about £1200 (at current fuel prices) over the estimated life of the system, and that does not take into account any maintenance/running costs. Now I know that the system cost the previous owners many times that figure...

As an earlier poster said, you would be better putting the cash in a good savings account and using the proceeds towards future bills. Whilst I am aware that fuel prices are rising, and will continue to do so, as Cardew says they would have to rise by many times before solar DHW would become financially viable. You also have to consider any cost of financing for a solar DHW system.

I would also say that it does not add any appreciable value to a house... it certainly didn't to this one when we bought it. Whilst there are house buyers who would find a solar DHW system attractive (as I did), I feel that there are probably an equal number who do not understand what these systems are capable of and would be unsure about the maintenance aspect.

Another issue is with the current trend for combi boilers - incorporating a solar DHW system into a combi circuit requires a very expensive mains pressure certificated solar cylinder, or the fitting of a standard solar cylinder, header tank and mains pressure and heat rated valves to switch the hot water circuit.

Solar DHW is very interesting, and environmentally friendly - but not moneysavingexpert

Skiduck

there is no trend for combi boilers, the converse is true - there is a trend for system boilers.

If like you say, you assume you save £60 per year on fuel costs through solar, which is quite a small saving. I assume you use minimal hot water and if it hadn't been for the panels being already installed, there would be no need for you to have solar, and no one should have recommended you have it.
Here is a calculation with fuel costs rising 10% per annum, which is way below current trends, in fact a single price increase a year would be nice, alas it is not the norm:

in 20 years you current £60 saving netts to: £3182.2

And as i say if you do use that little DHW, no one should advise you to have solar installed.
Any payback is relative, a single person showering once a day will never see any benefit in solar.
A household bathing once a night with between 3-5 occupants will.

Other things to consider if looking into solar:

Is your washing machine cold feed, if it is, there is no saving ther, however if it is hot and cold feed, there will be another saving.

Do you shower or bath, and in what frequencies?

If you have an electric shower, you will not see any savings, obviously.

Some more INDEPENDENT technical data for Cardew:


http://www.esru.strath.ac.uk/EandE/Web_sites/01-02/RE_info/active_urban.htm

http://www.eastleigh.gov.uk/docs/Case%20Study%202005.doc

http://www.clear-skies.org/communities/FeasibilityStudies.aspx

http://www.greenenergy.org.uk/sta/reference/documents/sta-microgeneration-response.pdf

Cardew

Skiduck wrote:

Some more INDEPENDENT technical data for Cardew:


http://www.esru.strath.ac.uk/EandE/Web_sites/01-02/RE_info/active_urban.htm

http://www.eastleigh.gov.uk/docs/Case%20Study%202005.doc

http://www.clear-skies.org/communities/FeasibilityStudies.aspx

http://www.greenenergy.org.uk/sta/reference/documents/sta-microgeneration-response.pdf

So show me where any of those state that solar is an economic proposition.

I've given you the information,

Where?
£6,000 payback in 15 years remember.

jonnyw_2

If we take your average of £3500 for an average system and even if your figures for savings and other assumptions are all correct, it still doesnt stack up yet.

Instead of buying a solar systen for £3500 put the money on deposit at 4% and let it compound over 20 years. You end up with almost exactly £3500 in interest, which is more than your saving figure. And the £3500 capital is still intact, not tied up in a solar system which has reached the end of its expected life.

It makes no sense at all if you are borrowing to put the system in.

If we stick with your £3500 for the cost of a system you need a saving of about 10% a year to make it worthwhile and cover the cost of replacement at the end of the 20 year period, which is £350 a year saved on water heating.

Now if solar is providing 50% of your hot water use you would have to be spending £700 a year on hot water for that to work.

Skiduck

Cardew wrote:

So show me where any of those state that solar is an economic proposition.



Where?
£6,000 payback in 15 years remember.

selective reading?

And with regards another posters issue of DHW usage, we serviced a hot water cylinder for a family 2 weeks a go, they use £95 to heat their hot water per month. As I keep saying again and again, solar is NOT suitable for everyone, but is very suited to some.

Solar in an oil central heating system tends to save an average of 1000 litres per year, check out your local supplier for price per liter at the moment. Our local supplier is @ 34.97 pence per litre, so without any further increases (which would be impossible) after 9 years, you save £3150.

You may not agree with the payback that people are quoting, however it is nearer the real payback than your calculations.

I am happy to agree with anyone, that,at the moment Solar maynot be 100% what the industry says, but it is virtually there. Obviously Solar PV has a long way to go, the low payback aside, the carbon footprint in the manufacture is very large.

jonnyw_2

Skiduck wrote:

Solar in an oil central heating system tends to save an average of 1000 litres per year, check out your local supplier for price per liter at the moment. Our local supplier is @ 34.97 pence per litre, so without any further increases (which would be impossible) after 9 years, you save £3150.

QUOTE]

Are you saying its 2000 literes a year to provide hot water via oil heating?

Are there any published figures to show this?

paul_h

Skiduck wrote:

Here is a calculation with fuel costs rising 10% per annum, which is way below current trends, in fact a single price increase a year would be nice, alas it is not the norm:

in 20 years you current £60 saving netts to: £3182.2

...but that still doesn't take into account leaving the cost of installation on high interest deposit for that 20 year period, or any maintenance, repairs or running costs.

Current fuel price trends are abnormal - most industry analysts are predicting energy prices to fall in the short to medium term, even BG are offering a guaranteed cut in prices after next year. I would agree with you, however, that long term energy prices are likely to rise, but to what degree is uncertain. When trying to guess what trends will be for the next 20 years, you cannot look at the last two years in isolation and ignore the previous twenty - fuel prices have been at an historical low for many years and are still haven't reached the highs of 25 years ago if inflation is taken into account.

Incidentally, our fuel costs have increased by about 20% over the last 6 years, not 10% per annum - we are on solid fuel, which I do admit is cheaper than most forms of domestic heating.

Skiduck wrote:

And as i say if you do use that little DHW, no one should advise you to have solar installed.
Any payback is relative, a single person showering once a day will never see any benefit in solar.
A household bathing once a night with between 3-5 occupants will.

Actually, we are a family with 2 small children, so we often run at least one bath a night - we use quite a lot of hot water and I would say our usage is higher than average. I have no axe to grind, in fact I like my solar panels - I'm just happy that they cost me nothing. The figures I have given are from experience, not from a book or sales brochure.

Solid fuel is cheaper than most forms of heating, but even so the average family home uses around 5000 KWh of DHW heating per annum - BG Click energy economy 7 tariff is around 2.2p per KWh on cheap rate in our area (East Midlands), so even with electric heating 5000KWh could cost as little as £110 per annum. A 50% saving from solar in these circumstances would only amount to £55 per annum.

However, if you were to use oil to heat your water, the saving would be more substantial - but then again, you may be better off using economy 7...

Skiduck wrote:

Solar in an oil central heating system tends to save an average of 1000 litres per year, check out your local supplier for price per liter at the moment. Our local supplier is @ 34.97 pence per litre, so without any further increases (which would be impossible) after 9 years, you save £3150.

2000 litres per annum is way off the mark. As I said, average family usage is 5000KWh per annum for DHW - if you specify and install domestic heating systems you should know that. That equates to around 650 litres of kerosene assuming your boiler is only 75% efficient, so an average user would save about 325 litres per annum.

In any case, anyone heating water with oil would probably be better off using economy 7 electricity.

Skiduck

jonnyw wrote:

Skiduck wrote:

Solar in an oil central heating system tends to save an average of 1000 litres per year, check out your local supplier for price per liter at the moment. Our local supplier is @ 34.97 pence per litre, so without any further increases (which would be impossible) after 9 years, you save £3150.

QUOTE]

Are you saying its 2000 literes a year to provide hot water via oil heating?

Are there any published figures to show this?

here ya go, done a few years ago, so costs for fuel and installationn have changed but obviously consumption hasn't.


http://www.energie-cites.org/db/belfast_140_en.pdf