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What are your biggest solar panel concerns?

Solar panels on roof

Today’s appeal judgement on solar subsidies might have you thinking about getting solar panels – and quickly, to get in before the new 3 March deadline. But there’s a lot more to consider before renovating your roof…

Solar households looking for a better rate of return through the Feed-in tariff (FIT) – the government scheme that pays you to generate electricity using solar PV panels – have been thrown a final lifeline. The high court has now decided to reject the government’s appeal against an earlier ruling.

This means the higher rate of FIT – 43.3p per kilowatt-hour (kWh), originally planned to be cut back in December – will apply for solar panels installed and registered before 3 March. After that, systems will get the new, lower rate of 21p per kWh.

Given all the headlines, the solar panels live Q&A session we’re holding over on Which.co.uk tomorrow is rather (though unintentionally!) timely.

Back in October, hundreds of you inundated our experts with your questions and comments during our solar panels live chat over on Which.co.uk, so we decided to run it again. I’ve summarised a few of the questions that came up last time round to get you warmed up…

The right roof position?

Solar panels need to be installed on a south-facing roof to make them work as efficiently as possible. But of course not everyone’s rooftops are perfectly positioned. So is it still worth bothering? Jim Kenney from Chelsfield Solar, a solar panel installation company, had this advice for one reader asking about his south-west facing home:

‘PV works well anywhere between east and west, so it sounds like your (south-west facing) roof is fine. Though you might want to find an installer who can give you an accurate estimate that compensates for orientation and inclination – it’s a pretty easy thing to do. From what you say I would expect your system to be about 6% below optimum south-facing.’

Is the cost coming down?

Long-term investment potential aside, you’ll still need to shell out for the cost of installing solar panels (unless you go for a rent-a-roof scheme – but that’s a whole different story). Given the increase in consumer interest, are the costs coming down?

Good news. Back in October, our policy expert Simon Osborn told several readers: ‘Costs have fallen by about 25% or so in the last year – so check that [your installer] is passing these savings on to you!’

According to the Energy Saving Trust, an average 3kWp system costs around £10,000 – read more about solar panel prices here.

Panel practicalities?

Thinking about solar panels? Then consider these factors:

Electricity meters: you’ll need to get a ‘generation meter’ installed so that the electricity your panels generate can be measured for your FIT payments. Ask for a full breakdown of your quote, so you can see if this is included in the cost.

Planning permission: usually you won’t need to get planning permission, unless in special circumstances – in conservation areas, for example – but speak to your local planning department before doing anything else.

Home insurance: solar panels shouldn’t affect your premium or cover – but you should inform your home insurer that you intend to install them.

Moving house: if you move, you could dismantle and take your solar panels with you, but you wouldn’t be able to continue to benefit from FIT payments.

Getting technical

I’ll be leaving the technical questions to our experts tomorrow, but suffice to say things got suitably geeky in our last Q&A, so you know where to come if you want to read about outputs, hybrid panels, inverters, evacuated tubes, shading assessment, optimisers and more…

You can join us live tomorrow from 12.30pm – sign up for an email reminder here. And while we’re sure to be discussing what the FIT ruling means for consumers, our experts will also be urging householders not to rush into any big decisions just to meet that March deadline.

What questions would you need answering before taking the plunge with solar panels? Has today’s FIT ruling made you think seriously about getting them installed?

Phil says:
25 January 2012

They’re ugly, disfiguring and potentially dangerous. I know of several that blew down in the recent high winds, fortunately they didn’t hit anybody, and more than one insurance company didn’t want to know.

Ugly? Disfiguring?

Would you prefer a wind turbine beside your house or maybe just a small nuclear power station. The population is increasing and more electricity is needed.

Please tell us about your solution, Phil.

Phil says:
26 January 2012

At least the nuclear power station, big or small, can be relied upon to produce electricity when it’s needed and not just when it’s warm and sunny or when the wind is blowing to the required strength.

The drawbacks of solar and wind power are obvious but many many would see solar panels as the lesser of evils compared with a nuclear power plant near their home.

Phil says:
26 January 2012

Until their lights go out.

steve says:
29 March 2012

I had solar panels fitted a year ago….Sorry Phil…but, they are not ugly, they are solar panels and solar panels look like solar panels. Calling them ugly is your opinion and you are entitled to it. But just because you say they are ugly does not make it so.
Neither are they disfiguring. What do they disfigure? They have not disfigured my house, nor any I have seen. They look like part of the house like a drainpipe or a letter box or a chimney.
As for ‘several blowing down in recent high winds’…when were these high winds? where abouts were these several that blew down? was it a news story? which news media reported it? or did you just happen to be passing by when these’ several blew down’ all at the same time (obviously just missing you)? It must have been an incredible sight seeing all these solar panels clattering down on to the street. how do you know ‘more than one insurance company didnt want to know’? Is it just a mind blowing coincidence that you happen to know all the homeowners of all the ‘several that blew down’ to obtain all this information????

There ARE documented instances of solar panels blowing off. This is usually due to the poor and inappropriate installs by incompetent contractors.

I have personally seen solar panel installations that actually overhung guttering and projected well above the ridge tiles – solar panels make great sails, and it does not take that much upwards force to damage a roof.

There appears to be little (if any) effective policing of either the physical install OR it`s compliance with Building Regulations/electrical regulations.

Beware – once the two year deadline is passed following commission of the install – you will be left to foot the bill for any corrective work YOURSELF.

Ebonie says:
31 March 2015

Hello Steve have you ever heard of the air source heat pumps at all? They run off your solar panels free of charge in the day time and aims to reduce your central heating bill anywhere between 60-80%, as you seem like quite a Eco person this is perfect to work in conjunction with your solar panels ! I’ve had both of mine fitted for over the year now , Deffinetly a thing for you to investigate in!

So we are still in a state of flux as to whether soemone installing solar panels now would get the higher or the lower rate of FIT….
By appealing to the Supreme Court, the 3 March deadline is still uncertain.

Has this all be done in order for the government to win time and leave us in a state of flux until as close as possible to the 3 March deadline?

As I have asked before, why is it that the government has been so keen to support wind farms and not to support “solar farms” that could benefit EVERYBODY.These could be placed in open country, on south facing slopes and on commercial and industrial roofs.A national scheme could create a lot of jobs.Perhaps the government has access to knowledge that indicates that at present the technology is not worth investing in.

Phil says:
25 January 2012

Very poor value for money. How long will they last? How often do they have to be cleaned & at what cost.
Just a gimmick but it keeps people in work I suppose.
Now if someone could develop a small independent generator that is economical, then I would be interested.

Perhaps a microCHP device such as these: http://www.microgen-engine.com/
I only wish they would produce a version that would run on heating oil such as they use in New Zealand.
Ideal for those of us without mains gas.
It seems a such an obvious advantage to drive a generator and still get the full heating effect as you burn your fuel.

The viability of solar panels relies heavily on the marketing blurb i.e. they are self-cleaning and maintenance free.

Both claims are total rubbish – but the industry chooses to keep the public in the dark.

Sarah says:
26 January 2012

I know I probably sound thick but does the latest ruling mean that if the installation is up and running before 03/03/12 the FIT will be at 43p (and index-linked) for the full 25 years? I was planning an installation in November but there were various problems and so didn’t make it in time for the deadline and therefore abandoned the idea. If the tariff will be at 43p for the full 25 years I would definately try to get panels installed by 03/03/12 provided I could find an installer with available time and equipment.

One of the major issues with home systems is keeping them clean – not an easy task for many installations.
The energy produced is actually limited by the dirtiest of the cells in the panel.
Having a ground installation can make things much easier perhaps as a communal system.

Can some expert tell us how to clean solar panels and what detergent to use if clean water is not sufficient.

Techfor Energy says:
17 May 2015

De-ionised water is what it required and many solar companies can now offer cleaning services if required, however, normal rainfall will keep the panels clean enough, unless you are under SAP producing trees – where you will need to clean the panels.

I have installed a 1.5kW immersion heater which should be able to heat water using my 4kW PV panel system and Sunny Boy inverter. I would like to be able to sense the ‘surplus’ power being generated and use this to control a relay in the immersion heater circuit so that the immersion heater only works when it can operate without any power being drawn from the grid.
Does anyone know a way of doing this?

Hi b.martin,
Thanks for your message and interest. I am afraid I cannot help with your cleaning query. We wee told that ours would be self cleansing.
In answer to your queries, The immersion heater is thermostatically controlled. The water is currently heated by a gas boiler with an indirect tank which also contains the immersion heater.
My intention was to heat by solar power when there was sufficient power available. I had hoped that I could sense when there was enough surplus power and then use this information to operate a relay in the power supply to the immersion heater to switch it on. I would accept that it would not operate when there was insufficient solar power and would use the gas boiler to top up as necessary. It too has a thermostat on the hot water tank. In summer, our main hot water demand is in the evening ie after the panels have heated the water.
I have had the panels in operation since October and power is being exported to the grid on good days. I anticipate that this will increase significantly as the spring arrives, with longer, warmer days and less electrical demand from lights, tumble drier, cooker etc.
My key interest in this is making use of surplus power by switching on the immersion heater when it can draw 6amps [1,5kW] without drawing any power from the grid. I need a means of sensing the surplus and a means of switching the immersion heater on only when there is that surplus. The existing immersion heater thermostat will control the switch on and off too.
Since my first query, I have discovered that my SMA inverter has the capability to have a ‘multi-function relay’ which may be able to power a relay to do the switching that I want. I am investigating that further too.

The term “self-cleansing” is essentially a meaningless term used extensively by sales personnel.

Anyone remember “self sharpening” – that was rubbish as well!

Techfor Energy says:
17 May 2015

Many devices now exist to do this – the iBoost is one of them and is more reliable than the older Immersuns

Before answering your query one would need to know the following details-
(1) Is your electric immersion heater fitted with a thermostat so that it will only switch on when the water in your hot water tank is below desired temperature ?
(2) How is your hot water heated at present and do you intend to switch the present heating off and rely solely on the immersion heater supplied from the solar panel ?
(3) Do you know the total daily kWh output of the solar panel and the and the total daily kWh export to the grid ?
(4) Do you use most hot water during day light hours or during the dark evening and night ?
(5) Are you prepared to be without hot water when the solar panel output is too low to supply the immersion heater ?
(6) At present what times during the day do you most electricity ?
Without some idea of the above it would not be possible to advise you.

One hinderance of using solar power is trying to find electricity tariffs that do not use two tier charges or a daily standing charge,
for example British Gas charges 26.559p for the first 170kWh and then 13.576p for the remainder,anybody got any ideas?

In response to your reply of the 8th I would make the following observations:-
I assume that your gas fired boiler provides space heating as wll as heating domestic water, hence it will be operating, when needed, 12 months of the year.
The auxiliary relay would need a setting of say 7 amps to allow for voltage fluctuations and it would need to measure export current not import, it would also be advisable to have a delay on switching on and off of 2 or 3 seconds to avoid minor transients. An alternative could be an export measuring kilowatt relay set at say 1.6 kW.
The immersion heaters thermostats should be set so that the electric immersion heater switches on just above the on setting of the boiler thermostat on a falling temperature and switches off just above the off setting of the boiler thermostat on a rising temperature. The final settings can only be obtained once the system is up and runing by a trial and error process.
The most important feature is to be able to accurately measure when the solar system is exporting sufficient power to make the extra complication worthwhile and to avoid both heaters operating together.
A first step could be to ask your present supplier if they would be prepared to fit an export kWh meter on an expetimental basis so that you could check how much power you are exporting and
I would be interested to know what the ‘ multi function relay’ in your inverter is able to do. My guess is that it will only be able to respond to total inverter output i.e. total generated not export.

Hello b. martin,
Yes, the gas boiler would be available to heat water 12 months a year but hopefully a reduced amount due to the heating of the water during the day with the immersion heater.
I understand what you are getting at with the measurement of export current. A measurement would need to take on board that the sensing of the export current to switch on the heater would reduce the export current by about 6 amps. I assume that is the point you were making with the 7amps you referred to.
I agree that the relative temperatures at which the two thermostats switch needs to be carefully controlled.
I have found a Technical Description of the Multi-Function Relay on the SMA web-site. This confirms that it can be used for ‘Optimization of Self Consumption’. It says ‘ ..loads can be switched on or off based on the power availability of the PV array. The minimum duty cycle is configurable.’ it also says that ‘The Multi-Function Relay allows you to activate and deactivate operational loads via the communication interface of the inverter.’ Other information requires a circuit breaker in the feed to a ‘contactor’ which would switch the load.

I am proposing the formation of an association fundementaly for small, local micro-generators who have invested in technologies that obtain the Feed-in Tariff, the proposed RHI, or any other subsidy. The initial purpose would be to offer suitable un-biased advice from experienced professionals in the respective industry’s, i.e, PV, Thermal, CHP, Biomass, etc with the aim to eventually become a strong lobby group to protect the investments made by its members from negative legislation changes or policy mishandling in the future.
If the moderator allows, I would be very happy to hear your views on this matter and would welcome the opportunity to discuss this further in this thread.
In response to Guy, if the SMA route does not match his expectations there is a very good commercially available Power Management system in the UK that allows for the switching of up to 4 appliances from power generated by the array and allows additional reporting on your electrical usage patterns via a connection to the signal output of your input meter. It was designed for the German market where the Feed-in tariff is payable only on PV generated power used in the home, not simply generated and exported.
If allowed, I will return to this thread and state the manufacturers UK web site.

Were you able to give the details of the Power Management system you referred to on 21 Feb?
Unfortunately I do not have the necessary knowledge but it seems a relatively simple thing to have a current sensor on the grid side of the suppliers meter that could sense the amount of current being exported, compare this with the amperage required to power the immersion heater [or any other device] and send a signal to a relay to switch it on. It would also need to drop out when the current fell below the level. Sensors were being given away at one time so that we could monitor how we used electricity but this would need to be able to detect whether current was flowing into or out of the house.

Any ideas on how I would go about this project?


once you have the solar system installed is there any consideration for choosing your electricity provider?

Do any providers offer more than the 3.1 p export tarif at all?

Are there any particularly averse to settling the feed in tarif or the bad with the documentation side?

Thank you


On 25th Jan Dave commented on Solar Farms & why the govt.was so intent on promoting Wind Farms as oppose to Solar Farms. Here in Shropshire, an energy company has submitted a proposalt towards erecting a huge farm costing some £22Million, with a turbine height of up to 125 Metres or about 410 feet in an AONB. That should destroy the visual appeal of the area quite comfortably.

One wonders why a Solar Farm, which would be at virtually ground level,- & therefore much easier to service – & visually be more like large greenhouses & certainly not viewable aginst the sky line was not submitted?

A possible aspect may be shown by the answer I received last year from the DECC to a letter I had sent to them. I suggested that in order to ‘future proof’ new buildings in respect of their anticipated Electrical Enegy need, that in order to obtain Planning Permission ALL new buildings ( Domestic & Commercial) must include Solar Panels. I further pointed out the Jobs & Business creation such legislation could induce.

i’m sure all of us have seen the Retail & Distribution parks around the country with their vast roof areas (eminently suitable for Soalr Panels).

The Depts. answer, stated that such legislation hadn’t been considered, but went on at length about Insulating the country’s 22 million homes over future years & to be nil Carbon by 2050!. They did however mention that ‘small scale local community owned energy svhemes’ would be encouraged!? however.

To my mind

Hear Hear.

If we wish to sort out our energy issue then governments need to make solar panels mandatory certainly in commercial buildings.

Trouble is the building industry is so conservative; if they had their way we would still be using wattle and daub.

One of the biggest problems with the industry is that there is no coherent policy!

To try and maximise the efficiency of Solar PV some provision must be made to STORE the energy.

Unfortunately, the gas industry seems hell-bent on the consumer NOT storing water (either hot or cold) and relying on instantaneous water heating.

A high efficiency, hot water storage cylinder is a very good way of storing energy for short periods of time – which is exactly what PV systems need as part of an integrated SYSTEM.

Please can somebody give an authoritative and unambiguous definition of the term ‘Total Installed Capacity’ (TIC) which it appears is key in deciding whether or not an installation is less than 4 kWp even though very strangely the installer is not required to record this figure on the MCS certificate only the Declared Net Cpacity which it appears is not relevant in determining whether an installation is less or greater than 4 kWp.

In the standard terms and conditions that electricity supply companies send out when registering installations this is what it says:

“Total Installed Capacity” means the maximum capacity at which an Eligible Installation could be operated for a sustained period without causing damage to it (assuming the Eligible Low-carbon Energy Source was available to it without interruption), a declaration of which is submitted as part of the processes of ROO-FIT Accreditation and MCS-certified Registration;

ande this is what it says about ‘Eligible Installation’

“Eligible Installation” means, on a Site, any Plant owned by the Generator which is capable of producing Small-scale Low-carbon Generation from the same type of Eligible Low-carbon Energy Source, the Total Installed Capacity of which does not exceed the Specified Maximum Capacity,
and which is more fully described in the Term Sheet;

Crucially the word ‘Plant’ is not defined in the terms and conditions.

My electricity supplier says that ‘plant’ means just the solar panels whereas my installer says it must be the whole installation including the inverter since the system cannot deliver electricity to the National Grid until the DC from the panels has been converted into AC by the inverter and that therefore TIC must mean the maximum AC coming out of the inverter not the maximum DC which can be supplied by the panels to the inverter.

I have looked at various internet forums and there is clearly considerable uncertainty about what exactly is meant by ‘plant’, and hence ‘TIC’ but the majority view appears to come down on the side of my installer rather than the electricity supply company.

Who is right and why?

If you are a domestic consumer with one set of solar panels feedind one inverter which in turn is connected to the electricity supply then the MCS certificate and the quoted decllared net capacity are the only details needed for the FIT scheme and the declared net capacity and total installed capacity are the same.

Thank you for this reply but unfortuantely my Electricity Supplier does not agree with you. I submitted a registration application form to them last November. Apart from an acknowledgement of receipt I heard nothing more for three months at which point I received an email from them asking how mnay panels had been installed and their maximum wattage. In my case this was 17 panels @ 250 W each. On this basis my supplier stated that my TIC is 4.25 kW and that the fact that the inverter limits the maximum possible output to 3.68 kW (ie. the declared net capacity was irrelevant to the TIC and that only the maximum DC output from the solar panels counts when calculating TIC not the the maximum AC output from the inverter. They also claim that they have Ofgem’s backing for this view which my installer is currently challenging. As a result they only propose to pay me 37.8 / kWh generated rather than 43.3 p.
Could you then please indicate whether your reply to my initial posting is your own personal view or whether it has an authoritative backing and if so what that is since knowing this will be very important to my installer (and of course me) as he pursues his challenge.

Reference your reply of 30 March the OFGEM regulations are as usual vague and open to many interpretations.Looking at the term TIC the word total means all not part of and the word installation also is all embracing since in the context of the FIT scheme a solar pv cell array is of no use without another device to convert the DC output of the pv cells to AC at the correct voltage and frequency to match that of the electrical system to which it is connected. Hence the capacity of the system is that of the lowest rated item in the chain, in your case it would appear to be the inverter at 3.68kW.
The OFGEM regulations do not specifically say that the term TIC only refers to the pv cells and not to the complete installation necessary for the system to work.
Have you contacted the Ombudsman on this matter?
However I am surprised that you have a pv cell array with a peak rating of 4.25kW and an inverter with a limiting rating of 3.68kW and that you have 17 pv cell panels, are the panels physically separate from one another or are they mounted as one block? If they are all sepatate from one another why was that necessary? I also cannot understand why you have a pv rating of 4.25kW and an inverter with a smaller rating.
One way out of your problem would be to have one or two of the 250W panels removed to bring the pv cell rating to 4kW or below but before doing this you should check that your Eligibity Date is in November 2011 and that if you change the rating the Elibibility Date wil not change to a date after the 3 March; your electricity supplier should have given you this date when they replied to you. If your Eligibility Date changes to after the 3 March your FIT payments will drop dramatically. Have you or they taken readings of your solar sytem generation meter either monthly or quarterly, without these readings you will not receive any FIT payments.