Questions
Solar Panel and Battery Storage FAQs
Straight answers to the questions we are asked most often about solar panels, battery storage, EV chargers, costs, planning and warranties. Each answer links to the page that covers it in full.
Getting a quote
Is the quotation free, and am I committing to anything?
The consultation, the indicative proposal, the survey and the written quotation are all free and carry no obligation. You are not committing to anything by enquiring, and you will not be asked to sign on the day of the survey. If the answer is no, that is a perfectly reasonable outcome for both of us.
What makes the quotation fixed?
It is issued after the property has been surveyed, so the things that usually turn into variations — scaffolding, consumer unit work, earthing, awkward cable routes, remedial roof work — have already been identified and priced. The price holds for the scope described. If something genuinely unforeseen appears once the roof is open, work stops and the position is agreed with you in writing before it continues.
How soon can you survey?
It depends on where the property is and how the survey diary looks that week. We will give you an actual date rather than a general assurance, and if a survey inside our working hours is difficult, say so in your enquiry and we will work around it.
Do you quote for battery storage on an existing solar array?
Yes. A retrofit depends on the existing inverter arrangement, the age of the system and the space available, all of which are assessed at survey. Our page on adding a battery to an existing installation covers what determines whether it is straightforward or not.
Will you give me a price over the telephone?
We will talk about ranges, and about what drives cost on a property like yours, so you can decide whether to go further. We will not give you a fixed figure for a roof nobody has looked at. A number produced that way is either padded or about to change, and neither is much use to you.
What happens to the details I send?
They are used to respond to your enquiry, arrange a survey and prepare a proposal. We do not sell enquiry data on to third parties. Marketing emails are sent only if you tick the optional consent box, and you can withdraw that at any time. The full detail is in our privacy policy.
How long does a domestic installation take?
Many domestic installations are completed in one to three days once scaffolding is in place, although the actual duration depends on system size, roof type, access, electrical works and whether a battery is included.
Do I have to be at home for the whole installation?
No. We need access on the agreed dates and someone available at the start, at the point the supply is switched off for the final connection, and at handover. The rest of the time you can carry on as normal, although the scaffold and the working route through the property will be in use.
Is the quotation fixed, or does it change once work starts?
The quotation issued after survey is fixed for the scope it describes. The point of surveying properly is that the things that usually become variations — scaffolding, consumer unit work, additional earthing, awkward cable routes — are identified before you are asked to commit. If something genuinely unforeseen is found once the roof is open, we stop, explain it and agree the position with you in writing before continuing.
Who actually carries out the work?
Depending on the service and location, work may be completed by Solar Fx or an approved installation partner working to our specification. Whoever attends works to the same written specification and the same installation standards, and the design, the quotation and the aftercare route stay with us.
When can I start exporting to the grid?
Once the system is commissioned, the network notification is complete and you hold the certification for the installation, you can approach a Smart Export Guarantee licensee and apply for an export tariff. The supplier sets its own rate and terms, and will normally ask for your certificate and meter details.
Can I visit the address on this page?
1 Loves Close, Burghfield Common, Reading, RG7 3NE is our registered office and operating base. It is not a showroom, and there is nothing there for a customer to look at, so please call before travelling rather than arriving unannounced.
How quickly will you reply?
Enquiries received during working hours are normally answered the same working day, and those received in the evening or at a weekend on the next working day. If a matter is urgent — a system you believe is unsafe, or water entering a property — telephone rather than emailing, and isolate the system if it is safe to do so.
Do you cover my postcode?
We work within approximately two hours of Basingstoke, with Reading and the surrounding Berkshire towns as our home patch. The coverage checker on the areas we cover page will tell you where your postcode sits, and the quote page has the same checker at the top.
Solar panels
How long does an installation take?
Most domestic solar installs are finished in one to two days. Adding battery storage or an EV charger can add a day. We'll give you a firm date at the design stage rather than a vague window.
Do I need a battery as well as panels?
You don't have to have one, but without storage the electricity you generate while you're out gets exported rather than used. An Anker SOLIX battery holds that surplus back for the evening, which is when most households use the most power. We'll show you both scenarios with your own numbers so you can decide.
What happens on a cloudy day, or in winter?
Panels still generate in diffuse light, just less than in full sun. Your system draws from the battery first and the grid second, so you're never without power — you simply buy less of it.
Will I need planning permission?
For most UK homes, roof-mounted solar falls under permitted development. Listed buildings and conservation areas are the usual exceptions. We check this for you before anything is ordered.
What warranty do I get?
30 years on the solar panels, 10 years on the battery and 10 years on the inverter from the manufacturers, plus our own 6-year workmanship warranty. The full terms are written into your quotation.
Can I add a battery or charger later?
Yes. We design every system so it can be extended, and Anker SOLIX capacity is modular — so you can start with what suits your budget now and build on it.
How many panels will fit on my roof?
Fewer than the roof area suggests, almost always. Panels must keep clear of ridges, hips, valleys, verges and vent tiles, and the layout has to line up with the rafters underneath. We measure the roof at survey and give you the real number rather than one calculated from a footprint.
Do I need planning permission?
For most houses, roof-mounted solar is permitted development subject to limits and conditions. Listed buildings, conservation areas and World Heritage Sites carry additional restrictions and may require consent. We check the designation for your address before designing anything.
What is MCS and do I need it?
MCS is the standards scheme covering both products and installers for small-scale renewables. You need an MCS-certified installation to qualify for a Smart Export Guarantee tariff, so in practice it matters for more than the paperwork.
Will solar work on an east or west facing roof?
Yes. South produces the highest annual total, but east and west arrays spread generation across the morning and evening, which often matches household consumption better — particularly with a battery. A north-facing roof is a different matter and we will tell you honestly when it is not worth doing.
How long do panels last?
Panels degrade slowly and predictably, and manufacturers publish both a product warranty and a separate performance warranty describing expected output over time. The specific terms depend on the product specified for your installation and are stated in your written quotation.
Do I need scaffolding?
For anything above single storey, yes. It is a safety requirement rather than a preference, and it is usually the largest non-equipment cost on a domestic installation.
Battery storage
Do I need solar panels to have a battery?
No. A battery on its own can charge from a cheap overnight tariff and discharge through the expensive part of the day, saving money on the price difference alone. It is a different economic case from a solar battery, but a real one — particularly for households with high consumption or an electric car.
What is the difference between usable and nominal capacity?
Nominal is the total energy in the cells. Usable is what you can take out without damaging them. A battery quoted at 10kWh nominal might give you around 9kWh usable. Always compare usable figures, because that is the capacity that does the work.
Will a battery power my house in a power cut?
Only if it is specified with backup or EPS functionality, and usually only for selected circuits rather than the whole house. It is a genuine feature, it needs designing in, it adds cost, and a standard installation does not provide it by default.
Can I add a battery to solar panels I already have?
Usually. It normally means AC coupling, because the existing inverter was not designed to manage a battery. Compatibility, inverter capacity, the condition of the existing installation and any effect on existing warranties all need checking first — which is why we survey before quoting.
How long does a battery last?
Warranties are typically expressed as a number of cycles, a throughput in MWh, or a percentage of capacity retained after a number of years — often all three, whichever comes first. Which measure binds depends on how hard the battery is worked. The specific terms for the product specified for your installation are stated in your written quotation.
Where should the battery go?
Somewhere cool, ventilated and reachable. A garage, utility space or an external wall in a weatherproof enclosure. We avoid lofts wherever there is an alternative: they are the hottest part of the house in summer, and nobody wants to service equipment through a hatch.
Why is there no battery price list on this page?
Because the cost of storage is set by the specification and the property rather than by the kWh figure on the box. The same usable capacity can be AC-coupled to an existing array, DC-coupled through a new hybrid inverter, or installed with backup functionality and a separate distribution board — three different jobs. We survey the property, confirm what it needs, and issue a fixed written quotation for the whole scope.
How do I compare two batteries on capacity?
Compare usable capacity in kWh, not nominal capacity, and check the continuous power output in kW alongside it. Then compare the warranty on the same basis: throughput or cycles, term in years, and the capacity retention promised at the end. A battery with more usable capacity, higher output and a longer throughput allowance is a different product from one that shares only its headline kWh.
Does a battery pay for itself?
That depends on how often it cycles and on your tariff, and it cannot be answered without both. A battery earns its keep by charging cheaply — from your own generation, or from the grid at a low overnight rate — and discharging when electricity would otherwise be expensive. The value of each cycle is the difference between those two prices, so a household that cycles the battery nearly every day on a tariff with a wide price spread is in a very different position from one that half-fills it a few times a week. Our payback page sets out the assumptions any such calculation depends on.
Do I need a battery to have backup power in a power cut?
A battery alone does not give you backup. Most grid-connected systems shut down in a power cut, for the safety of anyone working on the network. Running selected circuits through an outage needs an inverter that supports emergency power supply, a changeover arrangement and usually a separate backup board, all specified and installed for the purpose. It can be designed in, and it adds cost and complexity.
Can I add a battery to an existing solar system?
Usually yes. An AC-coupled battery with its own inverter can be added alongside most existing arrays without disturbing the original inverter. A DC-coupled battery normally means replacing the existing inverter with a hybrid unit. Which is appropriate depends on the age and condition of the existing equipment, the space available and what you want the battery to do. See our battery retrofit service page.
Is VAT charged on battery storage?
Electrical storage batteries were added to the list of qualifying energy-saving materials from 1 February 2024. Installation of qualifying materials in residential accommodation in Great Britain is zero-rated for VAT from 1 May 2023 to 31 March 2027, reverting to the 5% reduced rate from 1 April 2027. HMRC VAT Notice 708/6 sets out the conditions and is cited in the sources below.
Costs and payback
Why is there no price list on this page?
Because a price given without a survey is a guess, and a guess published as a price is misleading. The cost of the same array varies with the roof covering, the scaffold specification, the cable run, the condition of the consumer unit and the access to the property. We survey the property, then issue a fixed written quotation for the whole scope. If you want an idea of the order of magnitude before that, ask us and we will talk it through against your property rather than against an average.
What usually costs more than people expect?
Scaffolding, electrical remedial work and awkward cable runs. Scaffolding is a third-party cost that moves with elevations, height, duration and permissions. Consumer unit work is common in properties that have not had electrical work done for some years. A long DC or AC run needs larger cable and more containment. All three are established at survey so they appear in the quotation rather than as a variation once the scaffold is up.
Is a bigger system always better value per kWp?
Per kWp, usually yes, because the fixed costs are spread further. In terms of what the system returns, not necessarily. An array larger than your roof can carry sensibly, or larger than your household can use or export usefully, spends money to produce electricity at a lower value. Sizing is a design decision made against your usage pattern and roof area, not a matter of filling the roof.
Does VAT apply to a domestic solar installation?
Installation of qualifying energy-saving materials — including solar panels, and electrical storage batteries since 1 February 2024 — in residential accommodation in Great Britain is zero-rated for VAT from 1 May 2023 to 31 March 2027. From 1 April 2027 the 5% reduced rate applies. The treatment of commercial premises and of materials supplied without installation is different. HMRC VAT Notice 708/6 sets out the detail and is linked in the sources below.
Should I take the cheapest quotation?
Compare what is in them before you compare the totals. A lower figure often means a smaller array, a different panel, a generic mounting kit, scaffolding listed as provisional, or electrical work excluded. Once the scope is genuinely the same, price is a fair basis for a decision. Until then it is not.
Can you quote from aerial imagery without visiting?
We can produce an indicative proposal from imagery and mapping, and we label it as indicative. It cannot tell us the rafter centres, the state of the roof covering, the condition of the consumer unit, the cable route or the scaffold specification. Those are the items that most often move a price, so the fixed quotation follows the survey.
What is a typical payback period for solar in the UK?
We do not publish a typical figure, because a typical figure is an average of properties that are not yours and tariffs that may not be yours. Payback is the installed cost of your system divided by the annual benefit it produces, and the annual benefit depends on generation, on how much of that generation you use rather than export, on your import tariff and on your export rate. Change any one of those and the answer moves. Independent bodies such as the Energy Saving Trust publish illustrative figures on stated assumptions; those are industry figures, they carry the assumptions with them, and they are not a Solar Fx estimate for your property.
What is the difference between savings and export income?
A saving is import you no longer buy: a unit generated and used in the property, valued at your import unit rate. Export income is payment for a unit you send to the grid, valued at your Smart Export Guarantee rate. Import rates are normally higher than export rates, so a unit used at home is usually worth more than the same unit exported. That is why self-consumption matters so much, and why a calculation that adds the two together without distinguishing them is hard to check.
Does a battery shorten payback?
It changes the calculation rather than simply shortening it. A battery raises self-consumption, converting units that would have been exported at a lower rate into units that displace import at a higher rate, and on a time-of-use tariff it can also shift cheap overnight import into expensive periods. It also adds to the installed cost and has its own warranty life. Whether the additional benefit outweighs the additional cost depends on how often the battery cycles and on the price spread available on your tariff. Solar-only and solar-plus-battery must be assessed as two separate cases, on the same assumptions, and compared.
How should future energy prices be handled in a payback figure?
Openly. A payback period spanning several years contains an assumption about what a unit of electricity will cost in each of those years, and whoever produced the figure chose that assumption. A calculation that assumes prices rise steadily produces a shorter payback than one that holds them flat, from identical hardware. Ask what was assumed. If the answer is not available, treat the figure as an illustration rather than a projection.
Do solar panels add value to a property?
We make no claim about property values. Effects on sale price depend on the local market, the age and condition of the system, the documentation available and the buyer, and we have no basis on which to put a figure on any of that. What we can say is that a documented, certified installation with monitoring and a full handover pack is easier for a buyer and their surveyor to assess than one with no paperwork. Solar can also affect an EPC assessment, which our advice article on solar panels and EPC ratings covers.
Does the payback calculation change if I am often away during the day?
Yes, materially. Generation is greatest in the middle of the day. If little is being used in the property at that time, more of it is exported at the export rate rather than displacing import at the higher import rate, so the annual benefit from the same array is lower. Options include shifting loads such as washing, dishwashing or hot water into daylight hours, adding storage, or sizing the array differently. The right answer is a design question, and it is one of the things a survey and a proper usage discussion are for.
Planning, MCS and export payments
Does permitted development mean I need no paperwork at all?
It means no planning application. It does not remove Building Regulations, the DNO notification or your own obligations if you have a covenant or a lease. Many owners also apply for a Lawful Development Certificate so the position is documented for a future sale.
What if my house is in a conservation area?
Conservation areas carry additional restrictions. It does not mean solar is impossible, but the location of the array — particularly whether it is visible from a highway — becomes central, and consent may be required. Check with the local planning authority before designing the layout.
Are ground-mounted panels treated the same?
No. Standalone installations on land within the curtilage have their own limits and conditions, separate from roof-mounted equipment. Treat a ground array as a separate question rather than assuming the roof rules carry across.
Who confirms the position — you or me?
The local planning authority is the only body that can confirm it for your property. We will flag at survey where we think consent is likely to be needed and what the design implications are, but the determination is theirs.
Does Ofgem set the export rate?
No. The SEG obliges larger licensed suppliers to offer an export tariff, but each SEG Licensee sets its own rate, contract length and terms. The only floor is that the rate must be above zero. Rates therefore vary between suppliers and change over time.
Do I have to export to the supplier who sells me electricity?
No. Your import supplier and your SEG supplier can be different companies. Some households find the best combination is one supplier for import and another for export, though a bundled tariff can sometimes be simpler and better overall.
What is the size limit?
Eligible solar PV installations are up to 5MW capacity, which is far above anything domestic. Size is not the constraint for a household — certification and metering are.
Do I need a smart meter?
You need export metering capable of providing half-hourly readings, which in practice means a suitable smart meter. Without measured export, a supplier has nothing to pay against.
Which accreditations does Solar Fx hold?
Nothing is displayed on this page as held, because certificate numbers, the legal entity holding each certificate, expiry dates and a verification source have not yet been confirmed for publication. Where a certification is held by an installation partner rather than by Solar Fx, that will be stated when it is published. In the meantime, ask us directly and we will tell you what applies to your specific installation, in writing.
Why is a displayed logo not enough on its own?
A logo is an image file. It can belong to a supplier, to a subcontractor, or to a membership that has since lapsed, and displaying it proves nothing about current certification. The remedy is always the same: ask for the certificate number and the name it is held under, then search the public register yourself. A register entry is evidence; an image is not.
Does it matter if the certification is held by an installation partner rather than the company I contract with?
It matters for some things and not others. For an MCS certificate and for electrical self-certification, what counts is that the certified entity is the one carrying out and certifying the work — so you need to know which company that is. For a consumer code covering the sales contract, what matters is the entity you are contracting with. Ask which company sits behind each, and get the answer in writing before you pay a deposit.
Do I need an MCS certificate to be paid for exported electricity?
Suppliers offering a Smart Export Guarantee tariff will normally ask for the MCS certificate for the installation as evidence that it was installed by a certified installer using certified products. If exporting matters to you, establish before you sign anything which company will register the certificate and that it will be issued in your name.
Warranties and aftercare
How long is my warranty?
Warranty terms vary by manufacturer and product. The exact product, performance, inverter, battery and workmanship warranty terms that apply to your installation will be confirmed in your written quotation before work begins.
What is the difference between a product warranty and a performance warranty?
A product warranty covers the panel as an object — a defect in how it was made. A performance warranty covers its electrical output against a retained-performance curve, tested under standard test conditions. They are separate documents, with separate durations and separate claim tests, and a panel can be within one and outside the other.
Does the warranty transfer if I sell the house?
Manufacturer warranties usually attach to the installation rather than to you personally and pass to the new owner, sometimes on written notification to the manufacturer within a set period. Our workmanship guarantee transfers with the property to a subsequent owner. The exact transfer conditions for your products are set out in your quotation and in the manufacturer documents in your handover pack; tell us when you exchange and we will confirm what each provider requires.
My generation is lower than the estimate. Is that a warranty claim?
Not by itself. An estimate is a model of a typical year; actual generation depends on weather, shading, soiling and usage. A performance claim is made against the panel’s output under test conditions, not against an estimate. That said, an unexplained drop against your own previous years is worth reporting — it is usually a fault, and faults are what warranties exist for. Our guide to the <a href="/advice/signs-your-solar-system-is-underperforming/">signs a solar system is underperforming</a> sets out what to look for.
Who do I contact — you or the manufacturer?
Us, in the first instance, for any installation we carried out. We diagnose the fault, establish which cover applies and deal with the manufacturer on your behalf. You are not expected to work out whether a fault belongs to the panel, the inverter or the installation.
Are repairs to somebody else’s installation covered?
Not by the original installer’s guarantee, which we cannot claim under. Where we repair or replace part of a system installed by someone else, our own work carries its own cover, and any new component we supply carries its manufacturer warranty. The rest of that installation remains as it was.
EV charging
Why does the supply need assessing before you quote?
Because a 7kW charge point draws around 32A continuously, which is a substantial addition to a domestic supply. The assessment looks at the main fuse rating, the existing maximum demand with diversity applied, and what else in the house runs at the same time. Where the total would exceed what the supply can carry, the answer is load management rather than hoping the fuse holds.
What is PEN fault protection and why does it matter?
Most UK homes use a PME earthing arrangement, where the earth is derived from the incoming neutral. If that combined neutral and earth conductor fails in the street, exposed metalwork can become live. Indoors that risk is limited by bonding; outdoors, holding a car body while standing on the ground, it is not. Charge points must therefore either include PEN fault detection that disconnects the supply, or be installed with a separate earth electrode.
Do smart charging requirements affect what I can buy?
They affect what can legally be sold and installed. Charge points for private use must have smart functionality, default to charging outside peak periods unless you override it, apply a randomised delay to starting, and retain settings through a power cut. In practice this is built into the units, but it is why every current charge point wants a network connection during commissioning.
Can the charger run from my solar panels?
It can use surplus, which is different from running on solar. Most smart units offer a solar-matched mode that only draws what the array is exporting, throttling up and down as generation changes. Charging rates in that mode are modest and weather-dependent, so it suits topping up over a working day rather than a fast turnaround before a journey.
Can I have two charge points?
Often, with load management. Two unrestricted 7kW points on a typical single-phase supply is usually more than the service can carry alongside the rest of the house. Linked units that share a total current budget solve this, at the cost of both cars charging more slowly when they charge together.
Still have a question?
Call 0118 227 7444 or send us the details of the property, and you will speak to the people who would carry out the work.