In hot water. Again

[tetleys]

I recall receiving junk mail offering solar panels and thinking it's too good to be true, another negative was that these firms were charging £3000 or so.

 

We have recently been building a new house and living in a village with two 40" gas pipelines north and south but no domestic gas and fed up with being ripped off by oil magnates we have installed ground source heating and a couple of solar water heating panels on our south facing roof and no I do not expect the heating system to pay for it's self no more than my kitchen or bathrooms. However, we have been having unseasonably warm weather and as we aren't actually living in the new house yet and the threat of frozen pipes is probably past I decided to turn off the ground source heating that I run 24/7.

 

Any heating system always gives priority to warming domestic water and we don't need it. I installed a 280ltr or 61 gallon storage tank (the norm is 170ltrs) because of the solar panels.

 

The solar panels are recording up to 107c during the end of March and even during February when night temperatures fell to -19c if the sun was shining it was hitting 58c, the water in the tank without any additional heating source is over 60c and certainly too hot to bath or shower without adding cold we are having deep baths every night and the tank is topped up completely next day.

 

So yes, the panels do work, but I paid about £1400 for the panels and computerised pump, you'll need a water storage cylinder plus fitting costs but it won't cost £3000 and today the pump cost about 30p to run.

 

Go on save the planet.

[Welly]

I take it your system is purely for heating rather than one of those that can generate electricity and "feed" that into the Grid with heavy subsidy from the taxpayer? £3000 installation cost looks like it will pay itself off in less than 10 years - how long will your system last?

[28XX]

I have been watching this guy http://www.solarfriend.co.uk/index.htm for over 18 months. He seems really genuine and only wants to sell you his controller for £90. The panel idea is really neat, although I suspect it might not comply with water bylaws (if that kind of thing worries you). I have no choice but to do an east-west setup which will need additional controls.

[28XX]

Welly, the system tetlys has and that I want, only heat water. The government subsidized grid-feeding systems are photo-voltiac, i.e. they create electricity from sunlight. The hot water systems have been viable, if you buy sensibly, for a while.

 

The PV systems are only really viable while the subsidies are in force, and they are only subsidized for political reasons. Despite promises I would not trust them, given the long pay-back time and higher initial cost. Just reflect on all the other things the govt. has promised in the past. If you have the cash in a worthless savings account and you feel strongly about the environment it might be worth a punt.

[spamcan61]

PV solar can 'work' at the moment due to the insane billpayer subsidy, although making an even vaguely accurate prediction of electricity generated by PV panels over a few years is very tricky, with loads of assumptions to be made. There's plenty of photos of crazy installs on the net which won't pay back even with current FIT level.

[Southernman46]

and they make your house look shite too...........................

[The Stationmaster]

We went for solar water heating when we built the house and have a couple of panels working through a 210 litre hot water cylinder - I purposely went for a larger cylinder than the recommended size because i was vary f the impact of hotter weather and all that sort of thing so the extra water capacity does provide something of a heat dump.

 

I haven't checked any temperatures this week but I has a solely solar heated shower late yesterday afternoon and it was perfectly comfortable although probably a degree or two cooler than it would have been had the boiler been heating the tank. We normally only have the boiler set to heat the hot water cylinder for an hour at night and even with several people showering or bathing the solar copes fairly well with providing enough the rest of the time.

 

As far as economics are concerned the salesman was very honest (and I had called them, not the other way about) but he made one excellent point - if you don't spend the money on a solar system will it give you as big a return from deposit in a bank or building society as it would if you spent it on the solar? On current interest rates his point has, I think, turned out to be spot on - we have saved on gas costs but we have also had the cost of the solar heating system working for us instead of sitting in a bank depreciating.

 

As for Southernman's point - spot on, but we're in it, or in the garden, and we can't see the panels from either (and in any case they don't look too starkly different on a slate roof).

[tetleys]

I don't understand why we British only expect any heating system to pay for it's self and since self building it is a regular question but my stock answer is "when will your falt screen tele or leather setee pay for it's self?"

 

To me it's a bit like buying a diesel car (ignorring the torque and generally ease of driving) once the money is spent it's gone and no longer a consideration but the 'feel good' factor of not being constantly 'ripped off' virtually free hot water has to make sense.

 

I agree that my clay pantile roof would look better without the panels but I can live with it but I did draw the line at covering the roof with photo voltaics.

 

Every penny we save is more available for model railways or a whole host of better things than paying oil magnates.

[JohnR]

PV solar can 'work' at the moment due to the insane billpayer subsidy, although making an even vaguely accurate prediction of electricity generated by PV panels over a few years is very tricky, with loads of assumptions to be made. There's plenty of photos of crazy installs on the net which won't pay back even with current FIT level.

 

Actually, the amount of electricity a particular solar-pv array will generate can be very accurately predicted. Working out how much feed-in tarrif you get is a different matter!

 

My council is still serious about installing a solar-pv array on a local primary school, even with the currently reduced tarrifs. We've just had our electricity prices go up by 14% for the second year in a row, and we have carbon reduction targets to meet. Surprisingly, even with the reduced FIT, it can still make an acceptable payback - but by going for the cheaper Chinese-made panels, rather than the more expensive ones built in the UK.

[spamcan61]

Surely for an accurate prediction you need to know cloud/snow levels over the next 10 years in advance, plus the impact of aging of the panels, surface contamination, moisture ingress etc. for starters.

[stewartingram]

Does anyone remember the TV programme "House for the Future" fom the 70s or 80s? I was quite taken with this at the time, & even bought the accompanying book.

Essentially they took a rundown house in Derbyshire & rebuilt it, DIY style, incorporating as many money saving ideas as possible. I remember home-built solar panels heating the water (old radiators inside glass and wood frames); an electric wind generator (from a large oil drum, lampost and bus alternator), to name but two possible features. Still have the book on my shelf somewhere....

 

Stewart

[APOLLO]

The two 40" Gas mains you mention are no doubt "supergrid" high pressure bulk transmission pipelines, with operating pressures 250 psi up to 1000+ psi. Offtakes off these lines are mega expensive, pressure reduction stations requiring land & buildings, telemetry, multi stage pressure reduction equipment, etc etc. Then distribution mains and individual services have to be laid. Cost effective for large nos of properties fairly close together only. If your village had been economically "viable" it would have had gas years ago.

 

Back to solar. A flurry of activity around Wigan before Christmas last year when literally many dozens of council owned property (houses, schools etc) were fitted with large solar panel arrays. I understand the rush was to beat a reduction in the Government feed in tariffs. The council recieve the proceeds, with a small benefit returned to the property occupier.

 

Yes, solar panels work, though they are not cheap, have a life span, (don't know exactly, but say 20 years or so), and the government has just removed / downgraded a reason to install them (electricity). As for solar hot water - yes it's a good idea as Tetleys illustrates. You could almost make the things yourself, and indeed I intend to try my hand at one day !!.

 

Given the meteoric rise in energy consumption by us all - India & China especially - energy is just going to get more & more expensive over time. This country has very serious energy issues looming that will impact us all. So anything you can do for yourself utilising solar, wind etc MUST be a good idea. Just be carefull as there are alot of con-merchants about, talking / selling rubbish.

 

Simple things you can do right now to save energy, Install thermostatic radiator valves, turn down the boiler, room & cylinder stats, upgrade your programmer, shut doors & don't heat unused rooms (or low heat in freezing conditions).

 

Oh, and Insulate, Insulate & insulate.

 

Brit 15

[burgundy]

................ we have installed ground source heating ................................

 

Go on save the planet.

 

How do the economics of ground source heating stack up and how much heat does it generate?

Best wishes

Eric

[jcm@gwr]

don't heat unused rooms (or low heat in freezing conditions).

 

Oh, and Insulate, Insulate & insulate.

 

Brit 15

Unless you isolate [by insulation] the unused room, it is going to 'draw' the

heat from the rest of the house. So it is better to leave it on a low setting

with a TRV.

In fact it can be cheaper to leave the system on all the time and control it

with the master thermostat as the walls can take a lot of heating if they

cool right down. Talking mid-winter of course!

Totally agree with the insulation side of things though.

Jeff

[30801]

We've been mulling over the idea of a loft conversion lately and it strikes me that solar panels on the roof would also take away some of the energy that would otherwise heat up the new loft room.

Thoughts?

[The Stationmaster]

We've been mulling over the idea of a loft conversion lately and it strikes me that solar panels on the roof would also take away some of the energy that would otherwise heat up the new loft room.

Thoughts?

I don't get you on this. If you are going to have a loft conversion you are also going to finish up with modern levels of insulation which will stop a lot of the heat/cold transfer through the roof covering so a couple of square metres of solar panel won't make much difference as I see it.

[spamcan61]

 

So yes, the panels do work, but I paid about £1400 for the panels and computerised pump, you'll need a water storage cylinder plus fitting costs but it won't cost £3000 and today the pump cost about 30p to run.

 

Go on save the planet.

 

I don't doubt HW via solar can work, indeed I've been tempted myself, it's the PV stuff that's currently in vogue that's rather riskier.

[JohnR]

Surely for an accurate prediction you need to know cloud/snow levels over the next 10 years in advance, plus the impact of aging of the panels, surface contamination, moisture ingress etc. for starters.

 

We installed a 4.4kW array on a small school in 2005. Every year since it has generated within 2% of its original prediction. If anything, they've performed slightly better than anticipated. Its difficult to tell if thats because we've had more sun (which I dont think we have the last couple of years), or that the panels have deteriorated less than predicted. Certainly current modules are supposed to produce full power for longer than the older ones.

 

I think all the various factors you mention even out over time.

 

Oh and we are in the sunshine mecca that is North East Scotland.

[30801]

I don't get you on this. If you are going to have a loft conversion you are also going to finish up with modern levels of insulation which will stop a lot of the heat/cold transfer through the roof covering so a couple of square metres of solar panel won't make much difference as I see it.

Yeah, it depends on just how good these modern thin insulations are. It makes sense to consider doing solar panels at the same time as there's scaffolding up and wiring/plumbing going on.

Looking at other installations nearby it seems to be the done thing to plaster the whole roof in PV panels. Hot water systems seem to be rather smaller.

[The Stationmaster]

Yeah, it depends on just how good these modern thin insulations are. It makes sense to consider doing solar panels at the same time as there's scaffolding up and wiring/plumbing going on.

Looking at other installations nearby it seems to be the done thing to plaster the whole roof in PV panels. Hot water systems seem to be rather smaller.

I think you're quite right on the latter - I've got 2 sq metres of panels for my solar hot water, a bloke up the road has the entire southern of his bungalow hip roof covered in pv panels (and being a bungalow that is quite a big hip roof area).