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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?


B Martin
Thank you for this second reply. I fully agree that the Ofgem definition of TIC is vague and ambiguous and hence open to various interpretations. My energy supplier has, however, stated that it has been instructed by Ofgem to interpret it as number of panels x maximum wattage of each and that the effect of the inverter should not be included. As a result they will not budge from their postion that my installation has a TIC of 4.25 kW and that therefore they will only pay a FIT rate of 37.8 p (my installation was undertaken and commissioned in November 2011 with an eleigbility date of 20th November 2011). Like you my installer disagrees with the Ofgem intepretation of TIC and is in the process of taking legal action against the elctricity supplier and Ofgem to challenge this. So if you have any authoritative backing for your interpretation, other than your personal opnion, could you please say what it is as I am sure my installer’s lawyers would be pleased to know about it.
I have already suggested to the supply company that I just get my installer to remove one panel but they say that this is not a solution as it would require a new registration application which would, of course, come after 3rd March and therefore only qualifiy for a FIT rate of 21 p.
You ask why the installer fitted 17 250 W panels. I am advsied by an MCS consultant that the reason why this is a good idea is as follows:
‘If this is allowed by Ofgem for FITs it is quite clever and not mis-selling. The logic is that because the amount of sunlight has a curve that peaks each day, but also varies over the year – installing a 4.25kW panel but limiting it to <4kW will mean that it operates at 3.68 kW for more hours than a 4kW panel would and therefore generates more kWh.'
I am taking quareterly readings from the generation meter and supplying these to the elctricity company. However, they will, of course, not pay me any money until this matter is finally resolved.
Your further comments would be most welcome particuarly if you can give me an authoritative reference to back them up.

We have just paid £7000 for 10 panels, can you tell me why the energy firms take half of 4.3p per kw
when we have paid for for everything, surely we should get all the money as we paid for the insulation.

Mrs M Stafford (2.56pm May 2012)
Can you explain your comment?
1. Is your system a p v solar installation?
2.What is its kW capacity?
3.Are you a registered member of the F I T scheme? If you are a member you should have a certificate. The certificate will give your Eligibility Date which governs the payment that you should be receiving. What is your Eligibility Date?
4. In your comment should the final word be ‘installation’ not ‘insulation’?

J .O. says:
12 May 2012

Further to my previous comments regards planning and building regs requirements. I have spoken with both sectors who stated; 1. planning = As long as the property is not in a conservation area or a listed building go ahead and fit as no need for planning. 2. Building regs = providing the house is professionally surveyed and certified as being suitable ( usually done by the the sales firm ) no requirement.
I do wish front line civil servants could get their facts right, would have saved a lot of time and running about!!!

The Solar panel array must be certified (by a suitably competent person) as being complaint with Part A of the building regulations.

This can only be done POST installation.

One of my biggest concerns regarding Solar PV installations is the (seemingly) random approach to connecting them into your existing electrical system.

There are cases where, because of the way the system is connected, existing residual current devices (RCD`s) fail to operate AND inverters (the part of the equipment that converts the output of the solar panels to the same system as your existing mains supply) fail to shut down in the event of loss of supply.

Also, there are many cases of connections into socket outlets in bedrooms, immersion heater switches and existing socket circuits – this is simply NOT safe and does not comply with the Wiring Regulations, which Solar PV installers MUST adhere to. Worryingly, the vast majority of such connections are carried out by operatives with as little as five days “training” and NO experience. One has to wonder about the viability of any future Warranty claim ….

Unfortunately, complaints seem to fall on deaf ears, I suppose too much money is involved and as each Solar PV install gets slapped onto a roof, someone somewhere can tick another box for European Compliance or some other such rubbish.

The customer is paying for, and deserves, a much better quality of install and support.

Robert says:
7 July 2013

Swallow,did you get a difinative answer, I have a friend in a similar position,he is being asked to state the tic for his system.he has several roof angles and so a large number of actual panels.over 4.5 kw but never generates more than 3kw

Vernan says:
18 July 2013

I have seen in a price list of solar panels in the internet.A single solar panel which could produce 4kw,3kW,2kW respectively.I need this information for designing purpose.The prices I remember was pounds 2200 for 4kW panel.Could someone help me to find this seller.

Vernan says:
18 July 2013

Sorry add to my previous comment 4kW one panel price was Pounds 4220.00 in UK market.

Dave says:
11 June 2014

After having solal panels fitted I found that my electric bill as not gone down do you think it’s been I fitted properly

Guy says:
13 June 2014

My electricity consumption in kwh has reduced but the unit price has gone up.

Dave, To have an electricity bill that has increased after all the bother of installing solar panels must be the last straw. I would consider an independent inspection for a prior agreed fee. Check Which? Local to see if there any approved installers in your area. Anyone else had this experience?

Techfor Energy says:
3 May 2015

It is possible you have a Siemens consumption meter with a blue label, that adds your exported electricity (from the PV system to the grid) to the bill for you imported electricity from the grid.

There are one or two other makes of meters which also do this and can be found on the web.

Also reported here:


Ben says:
22 April 2015

Am I allowed to fit 2 gen meters on 2 different inverters on a 4kw system on the same system

The problem I’m having is the house is having 12 panels and the garage 4 but the garage has a distribution board. But to put the 4 panels from the garage with the house I will need to run a catanery wire.

Is there anything saying that I can’t just put a 1 kW inverter in the garage for the four panels with its own gen meter then a 3kw inverter in the house with a gen meter??!

Techfor Energy says:
3 May 2015

Why not do it slightly different ?

Run the garage PV system on a separate circuit, into a sub-distribution board (small fuse board) in the house, which also has the house PV system on it.

Then run that fuseboard’s cable into a single generation meter, then AC isolator, then into an MCB on the MAINS SWITCH side of your main house fuseboard, with an MCB big enough for both arrays, or if it is full, then join it to your main fuse board on a Henley block and tails.

Problem solved and MCS paperwork problems avoided with some small electrical work.

Wil Williams says:
30 April 2015

I am at the end house downa country, can the electricity supplier legally refuse to take my 4kw solar panel system “because the load on the line is too much “?

Techfor Energy says:
3 May 2015


Installs up to and including 3.68 kWp or 16A per phase (or a 4 kWp solar array with a 16A clamped inverter) can be connected to the grid without asking permission from the DNO and they will be informed within 28 days by your installer.

The DNO cannot refuse a grid connection within these limits.

Dominic says:
22 May 2015

I’m having solar panels fitted at this moment but am having a bad experience with the installer. They have been dragging their heals for the last 2 weeks and have still not got the system working. I have not paid a penny at this moment and would like some advice on what to do. Can I tell them to fetch there equipment off the roof because they have not stuck to the original sale of which was agreed and did not inform me of change and fitted a smaller system. Will I be liable for any bill from them if I get someone to remove the system and get another installer.

Techfor Energy says:
23 May 2015

Sorry to hear of your bad experience but as the system being fitted is NOT as

“… agreed and did not inform me of change and fitted a smaller system .. ”

Then they have breached the contract.

The reason they have dragged their feet is probably to get past the 14 days within which you can cancel, after signing your contract.

I would cancel in your shoes as the system being installed is not what you ordered and then find a good installer on Which? Trusted trader or CheckaTrade to come and do a proper job for you.

Good luck getting it sorted.

Hi Glenn, thanks for sharing some advice to this individual. However, we’ve had to slightly tweak your comment as we do not allow promotional content on the site. Feel free to have a read through our commenting guidelines. Thanks, mods]

Colin Duce says:
4 July 2015

Hi, I have 15 panels fitted with an owl intuition which produces a generation graph daily. When the weather is wall to wall sun as now the graph peaks at approx’ 2.8 Kw but when the weather is sun & cloud it can peak up to 3.5 Kw, why is this?

Hi Colin Duce

It is hard to know for sure without seeing your house and your solar PV system but one explanation can be that in this hot weather, efficiency of the PV modules can drop. This is because as the modules get hotter their efficiency decreases. However I wouldn’t have expected such a drop (3.5 to 2.8 kW).

On a very sunny day in the summer the temperature on the panels can be quite high. Was that sunny day when you recorded 2.8 kW last week when we had temperatures reaching 35 deg C? And are your panels black by any chance?

Despite what some people think, solar PV panels don’t need direct sunlight to work, just light. So an overcast but cool day could lead to more power being produced by your panels than on a very hot and sunny day.

Of course it could be something else all together. So if this problem continues, it might be worth asking your installer to come and check your system.


Can anyone here please let me know what it involves to remove a 16 PV solar panel completely including the electrical parts?

George G. usa says:
17 April 2016

Solar is great, but regardless of reality of cost in the interest of being upfront, I was searching for a physics answer and found these bright minds to pick so riddle me this: running in a rain storm increases the precipitation per square inch opposed to standing still and haveing zero motion. Can or will solar efficiency achieve the ability to maximize its chargeing rate of capture via the same physics paralell I.e movement expodentialy increasing the capture rate? Implications being a rotational or linear surface upon a wind turbine blade or car tire instead of Maybe the turbines mounting pole surface or a cars roof or bumper. As it doesn’t pertain to the immediate forum an answer is certainly desired by this user….please!?

Pete says:
20 April 2017

This won’t help. The speed of light is too high. You wouldn’t be able to move your solar panels fast enough. Rain drops are practically stationary by comparison

I think that nowadays solar PV panels are becoming more and more popular (at least in Ireland and it is not a country with a lot of sun). The main advantage is that they really help you to lower your electric bill. For example a company which I’ve contacted for my solar PV panels told me that are guaranteed to supply 90% of full power for 10 years. It’s something to think about,no!

The most important thing here is to contact a good installer as solar PV panels must be certified and must have warranty.