Solar and battery questions, answered

Most UK pitched roofs can take solar panels. What matters is how much unshaded roof area you have, which way the roof faces, its pitch, and the condition of the roof covering. Flat roofs and complex roofs with dormers, valleys or several small faces can still work, but the usable area is normally smaller than the total roof area. Our satellite assessment gives you an initial view within about a minute, and a technical review confirms suitability before any design is finalised.

It is a preliminary estimate built from satellite imagery and solar irradiance data for your own property rather than a national average, so it is a good early indicator of roof potential and likely generation. It cannot see roof structure, the condition of your tiles, your consumer unit, loft access or cable routes. Panel numbers, positions, inverter choice and any battery are all confirmed during technical design.

There is no fixed number. The starting point is how many panels your roof could physically hold; the right number then depends on how much electricity you use each year, how much of your generation you would use in the home rather than export, whether you are adding a battery, and the inverter and grid connection design. A household using around 3,000 kWh a year needs a very different system to one with an EV and a heat pump.

Roof capacity is a physical measurement: the largest array that fits in your usable roof area. A recommended system is a design decision that also accounts for your electricity consumption, budget, inverter sizing, battery plans and grid connection requirements. Filling a roof with panels you rarely use the output from is not automatically better value, so the recommended system is frequently smaller than the maximum the roof could hold.

Most domestic roof-mounted solar installations in the UK fall under permitted development, provided panels sit reasonably close to the roof plane and do not protrude above the highest part of the roof (excluding the chimney). Listed buildings, conservation areas, some flats and certain flat-roof or ground-mounted arrangements can need consent. Where there is any doubt, we identify it during technical review rather than assuming.

Yes. Panels generate from daylight rather than heat, so they produce electricity throughout the UK winter — just less of it, because days are shorter and the sun is lower. Expect the strongest output from around April to September and a noticeably lower contribution in December and January. Cold, bright days can actually be very productive, because panel efficiency improves slightly at lower temperatures.

No. South-facing roofs give the highest annual total, but east and west facing roofs still generate well and shift output towards the morning and afternoon, which often matches household usage better. East/west splits across two slopes spread generation across the day rather than peaking sharply at midday. North-facing slopes are generally not worth using on their own.

Generation depends on system size, orientation, pitch and shading. As a broad UK guide, each installed kilowatt-peak (kWp) of well-oriented roof-mounted solar typically produces somewhere in the region of 750–1,000 kWh a year. Your assessment uses solar irradiance data for your specific roof faces rather than that generic range, which is why two neighbouring houses can return different figures.

Solar panels are long-life equipment. Manufacturers commonly provide product warranties of 12–25 years and performance warranties covering output over roughly 25–30 years, with a small annual efficiency decline. Inverters have a shorter service life than panels and may need replacing during the system's lifetime. Exact warranty terms depend on the equipment specified for your installation.

Yes, and it is one of the best ways to use your own generation, because charging is a large, flexible load that can be shifted into daylight hours. A compatible EV charger can prioritise surplus solar, and some tariffs let you top up cheaply overnight as well. If you already have an EV or plan to get one, tell us at assessment stage — it usually changes the appropriate system and battery size.

They work well together, and both run on electricity, so a heat pump raises your annual consumption and makes more of your own generation useful. The caveat is seasonal: heat pump demand peaks in winter when solar output is lowest, so solar offsets part of the annual running cost rather than most of the winter heating load. Sizing needs to reflect that.

No — solar works perfectly well without one. A battery matters if a lot of your electricity use happens outside daylight hours, because it stores surplus generation for the evening instead of exporting it. If you are at home during the day and already use most of what you generate, a battery adds less. We look at your usage pattern before suggesting one either way.

Battery sizing is driven by how much electricity you use outside generation hours, your annual consumption, the size of your array, any EV or heat pump, your tariff and whether you want backup capability. A common domestic range is roughly 5–15 kWh of usable capacity, but the right figure is the one you can genuinely cycle most days. Bigger isn't automatically better: capacity that sits unused still costs money.

It can supply your home in the evening and overnight until the stored energy is used up. Whether it covers the whole night depends on usable capacity, how much surplus was stored that day and what you are running — a fridge, lighting and a television draw far less than an oven, immersion heater or EV charger.

Most modern home batteries can charge from the grid as well as from solar. On a time-of-use tariff with cheaper off-peak periods, that lets you fill the battery when electricity is cheapest and use it at peak times. Whether it is worthwhile depends entirely on your tariff and consumption, so it should be assessed rather than assumed.

Usually yes. A battery can be retrofitted to an existing solar installation, typically using an AC-coupled battery with its own inverter, or a DC-coupled battery where a hybrid inverter was installed at the outset. Planning for storage at design stage keeps the later upgrade simpler and can avoid replacing the inverter, so it is worth telling us your intentions early.

Not automatically. Many solar and battery systems shut down during a grid outage for safety reasons. Backup during a power cut requires equipment and wiring designed for it — typically a battery and inverter with backup capability plus a separate protected circuit or changeover arrangement, which is usually specified as an option rather than included by default. If outage backup matters to you, say so before design so it can be quoted properly.

Home batteries are usually warranted for a set number of years or cycles — commonly around 10 years, often with a stated end-of-warranty capacity such as retaining a defined percentage of original capacity. Real-world life depends on how deeply and frequently the battery is cycled, and on temperature. Specific figures depend on the product specified for your system.

No. A battery can be installed on its own and charged from the grid on a time-of-use tariff, then discharged at peak times. Paired with solar, though, it does two jobs — storing your own free generation and shifting grid purchases — which is why the two are so often installed together.

We don't publish a single figure, because domestic solar prices genuinely vary with system size, panel and inverter choice, whether a battery is included, scaffolding requirements, roof complexity, the electrical work needed and any grid connection requirements. A small array on a simple accessible roof and a large array with storage on a complex three-storey roof are different projects. You receive a written breakdown before committing to anything.

Savings come from two things: electricity you no longer buy because you used your own generation, and payment for exported surplus if you are on an export tariff. That makes your saving dependent on your consumption, your unit rate, how much generation you use in the home and whether you add a battery. Our estimate uses your own roof data and the usage figures you enter, and it states the assumptions behind it.

Two 10-panel systems can differ in scaffolding requirements, roof covering and complexity, cable routes, consumer unit condition, inverter type, whether storage is included and equipment quality. Access and electrical work are real costs that have nothing to do with panel count, which is why a quote should be read as a whole rather than compared purely per panel.

The Distribution Network Operator is the company that owns and operates the local electricity network in your region — the cables, substations and connections, as opposed to the supplier that bills you. Because solar exports electricity into that network, generation equipment has to be notified to, or approved by, the DNO under the industry connection rules.

G98 is the industry standard covering the connection of small generation equipment. Many domestic installations connect under this route, where the installer notifies the DNO that the equipment has been fitted, commonly within 28 days of commissioning, rather than waiting for prior approval. The relevant limit is based on inverter capacity per phase, not on the number of panels.

G99 covers larger or more complex generation connections, where an application is made to the DNO and approval is granted before the equipment is connected. Domestic projects can fall under G99 when the inverter capacity is above the small-generation threshold, or where there is existing generation or a network constraint. It adds a step to the timeline rather than being a problem in itself.

G100 describes an approved arrangement where equipment actively limits how much electricity a site can export to the network. It allows a larger generation or storage system to be installed on a constrained connection, because export is capped by a monitored control scheme. It affects export, not what you can generate and use in the home.

Whether your system needs prior approval or notification after installation depends on inverter capacity, the number of phases at your property, any battery storage, any existing generation and the local network. Panel count alone does not determine it. Where an application is required, we prepare and submit it as part of your project, and we never describe a system as approved before it is.

Most domestic installations are completed within one to a few days on site once scaffolding is up, depending on system size, roof complexity, the electrical work involved and whether a battery is included. The overall project timeline is usually longer than the installation itself, because it includes technical design, grid paperwork and scaffolding scheduling.

Scaffolding is erected first, which is the most visible stage. Roof work happens outside; the inverter, any battery and the electrical connection are inside, typically in a loft, garage or utility space. You should expect at least one planned interruption to your electricity supply while the system is connected, and some drilling noise. Rooms need clear access to the working areas.

Safe roof access is arranged and scheduled as part of your project, so it is in place for your installation dates rather than being something you book separately. Access requirements depend on your roof height, the property type and whether the working area can be reached safely.

The system is tested and commissioned, monitoring is set up so you can see generation and consumption, and you are walked through how the system, any battery and the isolation points work. You then receive your handover documentation, which is also what you need for your export arrangement with a supplier.

Very little. Panels have no moving parts and UK rainfall keeps them reasonably clean on most pitched roofs. Sensible practice is an occasional visual check, keeping the array clear of overhanging growth and moss, and watching monitoring for an unexplained drop in output. Inverters and batteries have their own service expectations set by the manufacturer.

Monitoring gives you daily and long-term generation figures, so a fault or a new shading problem shows up as a change against previous performance rather than going unnoticed. Comparing like months with like — this April against last April, not against midsummer — is the practical way to read it.