Hi,
Does any one know of a site where you can roughly work out how mush money you will save with solar panels. We are thinking of getting them put we need to work how much we will save and how many years it would take to get the money back.
Thanks
Nigel
On 23 Sep 2006 11:29:56 +0200 someone who may be "Nigel" wrote this:-
If you are only considering simple payback then if you DIY it will probably take a decade to recoup the expenditure at current gas prices. In terms of money there are other things to do first.
However, there are other reasons to install solar water heating.
Predicting future energy prices is also a good game.
-- JJ
There used to be useful stuff on this stite, I've not checked for a few years though
The consensus seems to be ( dons tin helmet ) that these things will never pay for themselves if installed professionally. One might as well take the umpteen thousand and put it in the bank at 5%. I've seen costs of £13,000 mentioned! That'd return £650/year at 5% not including the effects of compounding. Try and squeeze £650/year out of a solar panel(s), and you lose your capital as well.
Even installation costs of half that could still not recoup the outlay.
The way to evaluate these things is to see what the annual saving is as a percentage of initial outlay, expressed as a percentage. Would you put your money in a bank that returned 1% or 2% and kept the capital ?
I would say the only way to get a decent return is if you DIY the lot, with a good situation i.e. a south facing roof.
As has been mentioned, if you want strategic isolation from the vagaries of the gas and electric supply, that's another thing altogether.
You forgot to say which type of solar panels, PV, hot water or space heating. PV will never pay its cost back, unless youre a long way from the grid, HW can if its well enough designed, a lot of systems dont, and space heating is the one with the lowest cost and highest return.
Re a ready calculator site, there is no way the technology is nearly simple enough to do that. There are so many design choices, it depends on the house etc etc etc etc. The nearest I've found is news:alt.solar-thermal, where at least they can give you some guidance with making choices and working it all out.
NT
The question isn't specific about what is meant by 'solar panels'. It could mean pv, which isn't economical in Britain, if solar water heating panels is meant it IS economical.
Solar water heating panels wouldn't pay on your figures but they don't have to cost anything like that - ours didn't.
That's ridiculous.
Ours was a sixth of that price. I think you've been watching television :-)
...
a) this IS a DIY group, installation isn't difficult.
b) of course a south facing aspect with no shading is the best, it wouldn't be suitable to use any other site.
I'm VERY enthusiastic about our system, it's been working since January and we've hardly used the boiler at all in that time. The meter reading was queried because it was so low. Today isn't warm and it's been raining but we have a large cylinder full of water at 40.7 C - a very useful temperature. Even when the sun doesn't shine there's a noticeable heat gain. When the sun shines even though the air temperature is low the water is heated.
It's sensible to organise water use to take advantage of the heating, for instance by washing clothes at night rather than in the morning, when there will have been a small drop in temperature.
Mary
Please enlarge on this! We have double glazing; draught proofing; a full layer of insulation in the attic. What do you suggest now, before going for solar panels?
And what are those other reasons?
Take care,
Insulate the walls.. very effective.
What BiBoffin said, cavity wall insulation. For instance, a gas heated semi can get cavity wall insulation for £260: for other circumstances have a look at the sites that abound.
Using my criterion of equivalent interest rate, cavity wall insulation has to save
5% of £260 per annum to compete with the bank ( more if you want your capital back in the end ). Now cavity wall insulation is guaranteed for 25 years, lets say it does what it says on the tin, you want about an extra £10 back per annum on top of the 5% to recoup your capital outlay. 5% of £260 is £13, so adding £13 and £10 we need to save £23 per annum to break even.The figures for a typical cavity wall that are given is about 35% of the heat loss of a house. It could be more if the loft is well insulated and the windows are double glazed and the leaks are sealed.
Anyway, let's also assume £400 per annum heating gas bills. I think I spend something like that, it's unlikely to be too far off. That means perhaps £130 of the heating bill is leaving through the walls each year. We need to save £23 of that to break even, so unless cavity wall insulation is really inefficient I reckon it's a no brainer that cavity wall insulation will not only break even but may well be in profit in as little as 5 years.
OK, I plucked a lot of those figures out of thin air, but you see the method I'm employing to make a decision.
If solar waterheating can come in well below the figures I've heard talked about, then maybe it can be worthwhile, but I would like someone to present a set of figures to me detailing capital outlay and return in energy savings that exceeds 5%/annum and returns your capital in
One is reducing the amount of fossil fuel you use. You don't say how you curently heat your water but it's probably a pretty safe assumption that you burn a fossil fuel (gas or oil) localy. If electricity most of that is generated by burning a fossil fuel...
Thanks for all the feedback. The problem we have got is that we live in the Alps so the sunlight in the winter is quite short as soon as it dips below the mountain the sun is gone.
However we do have a south facing roof so it does get a fair bit of sun. How does the snow affect it??
thanks again
Nigel
On Sat, 23 Sep 2006 10:36:47 GMT someone who may be "Jason" wrote this:-
They have been going upwards for a long time. There has been the occasional downward movement for a while, but the trend upwards.
On 24 Sep 2006 08:47:35 +0200 someone who may be "Nigel" wrote this:-
Depends how much show there is. A UK group is probably not the place to ask about this.
On Sat, 23 Sep 2006 16:10:39 GMT someone who may be "Bioboffin" wrote this:-
Others have mentioned the walls. There is also the question of the floors. Having sealed up the house tightly you might like to consider total house ventilation, with heat recovery. It may be that a wood burning stove would provide useful heat input too. You didn't say how the water is currently heated.
Don't be fooled by advocates of solar space heating. It may work well in a location where there are cold nights and sunlit days. However there are few deserts in the UK. In the UK solar space heating can reduce the load on other forms of heating during spring and autumn, but it is not an all year system. If you have a suitable house a passive design, can be added on, but don't expect too much.
You also need to consider hot water consumption. Have you minimised this? Are the hot water pipes insulated and the runs minimised?
Electricity generating panels are still uneconomic if measured on simple payback, or discounted cash flow. However, this will change.
Reducing carbon emissions, reducing reliance on external supplies, doing one's bit, a warm green feeling. There can be many reasons, everyone is different.
Thanks to all who replied to this. We have a problem with cavity wall insulation because the house has a wood frame, and I understand that cavity wall insulation is not an option for us. We heat the house using a (newish) gas boiler, and fuel bills are quite low (£70/month for gas and electricity combined) - for a semi. As we are expecting to move in a few years time, it would not be cost-effective for us to install some kind of solar system.
I thought that modern timber framed houses had wall insulation built in.
That's not LOW!
It would probably increase the value of your house and save money for you in the meantime.
Mary
It will block the sunlight until it melts. The snow on the panel might melt more quickly than that on the rest of the roof.
Mary
Ours does, but apparently the amount put in varies quite a lot. There is a minimum standard which is fairly inadequate.
Until three months ago, we were paying £40/month (for both), but the supplier bumped it up a bit probably in anticipation of higher bills following recent fuel increases. We probably actually use somewhere around £50/month over the year as a whole. Apparently the average bill in the UK last February was £68/month, so we are using less than average. Hence the word 'low'.
You have a point, but I'm not yet convinced that it would be a cost-effective improvement for us. I suspect that most house buyers tend to be more impressed by modern-looking kitchens than by solar cells on the roof.
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