Solar Installation in the UK: Process, Timeline and Cost

A UK solar installation runs from survey and quote through planning checks, scaffolding, one to three days of roof work, commissioning, the network operator notice and the MCS certificate. Expect six to twelve weeks in total. In 2025/26 the median system of up to 4 kW cost £1,780 per kW in government data, and installation in a home carries 0 % VAT until 31 March 2027.

This guide covers a conventional rooftop or ground-mounted system wired into your consumer unit by an installer. If you want a small kit that plugs into a socket, the rules are different and much lighter: see is plug-in solar legal in the UK and the comparison of all kit types in our guide to solar panel kits in the UK.

The installation process at a glance

A domestic solar project has more paperwork than roof work. The panels, rails and inverter go in quickly; what takes time is the survey, the design, any permissions and the network operator. The table shows the usual sequence and who does what, based on the MCS rules, the network codes and the planning rules described further down.

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The durations are our estimates of a typical project, not regulated times, except the 28-day G98 notice and the 30-day MCS certificate, which come from the network code and the MCS rules.

Step one: quotes, survey and what a good quote contains

Most installers start with a remote estimate from satellite images and your annual electricity use, then send a surveyor. The survey decides whether the estimate survives contact with the roof. A surveyor checks the roof covering (concrete tiles, clay tiles, slate or a flat membrane), the condition of battens and rafters, the shading from chimneys, trees and dormers, the route for the DC cables, the space for the inverter and any battery, and the state of your consumer unit and earthing.

A quote you can compare should name each component and the reasoning behind its size. Under the MCS scheme, the installer must follow a pre-sale information standard and give a system performance estimate, so ask for both in writing.

What to check in a quote, and why:

• Panel model, number and peak power. Roof panels in the kits we looked at in November 2026 were about 450 W each and measured roughly 1.76 by 1.13 metres. Nine such panels give about 4 kW and cover about 18 square metres.
• Inverter model and AC rating. A 3.68 kW inverter on a single-phase supply keeps the system inside G98. A larger inverter means a G99 application and possibly a delay.
• Mounting system. On-roof rails with hooks under the tiles, in-roof trays that replace tiles, or ballasted frames on a flat roof. Each has its own weatherproofing method and its own warranty.
• Yield estimate. It should state the orientation, tilt and shading assumptions. If a figure looks high, compare it with the PVGIS figures in the yield section below.
• Scaffolding. Included or not, and for how many days.
• Electrical work. Isolators, any consumer unit upgrade, the generation meter and whether a new earth electrode is needed.
• Battery. Usable capacity in kWh, power in kW, warranty years and cycles.
• Paperwork. G98 or G99, Building Regulations compliance, MCS certificate, electrical installation certificate, handover pack.
• Payment terms. Deposit amount, how it is protected, and when the balance is due.

If you are still deciding how big the system should be, our guide to solar panel sizes in the UK explains panel dimensions and how many fit on a typical roof.

MCS and RECC: what certification gives you

MCS (originally the Microgeneration Certification Scheme) certifies installers and products for small renewable systems. An MCS-certified installer is assessed by a certification body against an installation standard and must use MCS-certified products. The installer registers each job and raises an MCS certificate, which is the document that proves the system meets the standard.

The current MCS Installer Operating Requirements, issue 2.0 dated 8 September 2026, set out several duties that matter to you as a customer:

• the MCS certificate must be raised within 30 calendar days of commissioning;
• the installer must share the MCS Customer Commitment with you before you sign;
• you must receive a written guarantee covering the system’s design and the workmanship, plus an MCS-approved form of financial protection;
• if a complaint is not resolved through the MCS complaints process, the installer must take part in alternative dispute resolution with a provider appointed and funded by MCS.

RECC, the Renewable Energy Consumer Code, is a separate consumer code approved by the Chartered Trading Standards Institute. Its members agree to rules on sales tactics, model contracts, deposits and performance estimates, must give a workmanship warranty of at least two years, and give customers access to an independent dispute resolution service at no cost. RECC notes that in many cases you have 14 days to cancel a contract without penalty, depending on how and where the contract was made.

MCS matters for one more reason: money. Without an MCS certificate or an equivalent, Smart Export Guarantee suppliers are not obliged to pay you for exports from a solar system of up to 50 kW. We cover that in the SEG section below.

Planning permission: England, Scotland, Wales and Northern Ireland

Planning is devolved, and each nation writes its own permitted development rules. For an ordinary house, roof panels are permitted development in all four, which means no planning application, provided the limits below are met. Flats, listed buildings and protected areas are where most projects need a closer look.

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England

Class A of Part 14 covers solar equipment on a house or a block of flats. On a pitched roof the panels may not protrude more than 0.2 metres beyond the roof slope or rise above the highest part of the roof, chimneys excluded. On a flat roof they may stand up to 0.6 metres above the highest part of the roof; on protected “article 2(3)” land, which includes conservation areas, you must first ask the council whether its prior approval is needed. Equipment must be sited, so far as practicable, to minimise its effect on the building’s appearance and the amenity of the area, and removed when no longer needed.

The class excludes listed buildings and scheduled monuments. In a conservation area or World Heritage Site, panels may not go on a wall, balcony or roof enclosure that fronts a highway. Ground-mounted arrays in the garden fall under Class B, with limits on area (9 square metres) and on height near boundaries. The order was last amended on 27 August 2026 to add plug-in solar; those changes are covered in our plug-in solar planning permission guide.

Scotland

Scotland widened its rules from 24 May 2024. Class 6HA allows solar on a dwelling as long as it does not protrude more than 1 metre from an external wall, roof plane, ridge or chimney. It does not apply to listed buildings, buildings in their curtilage or World Heritage Sites, and in a conservation area it excludes the principal elevation and any side elevation fronting a road. Scottish councils issue a Certificate of Lawfulness if you want written confirmation.

Wales

Wales applies Part 40 of its own permitted development order as amended in 2012. Panels on a wall or pitched roof may not protrude more than 20 centimetres beyond its plane nor rise above the highest part of the roof. In a conservation area or World Heritage Site they may not go on a wall forming the principal or side elevation that fronts a highway. The Welsh order counts a building made up wholly of flats as a dwellinghouse, which helps blocks.

Northern Ireland

Northern Ireland’s order allows solar PV on the roof of a dwelling or a building in its curtilage. Panels may not protrude more than 20 centimetres beyond a roof slope that faces onto and is visible from a road, may not exceed the highest part of a ridged roof or stand more than 1.5 metres above a flat roof, and may not extend beyond the edge of the roof. In a conservation area or World Heritage Site, a roof slope or flat roof visible from a road is excluded. A free-standing array is allowed if it is the only one, no larger than 14 square metres, no higher than 2 metres and not nearer a road than the house.

Listed buildings and conservation areas

Listed building consent is a separate regime from planning. In England and Wales, section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires consent for works that affect the character of a listed building, and carrying them out without consent is a criminal offence. Scotland and Northern Ireland have equivalent laws. Panels on a rear roof slope that cannot be seen from the street are sometimes approved; panels on a principal slope rarely are. Speak to the council’s conservation officer before paying a deposit.

A council can also remove permitted development rights in a defined area with an Article 4 direction. Councils publish these, and an installer working locally usually knows where they apply.

Building Regulations: structure and electrics

Planning decides what the house looks like; Building Regulations decide whether the work is safe. The Planning Portal says Building Regulations will normally apply to roof panels in England: the roof’s ability to carry the weight must be checked and proven, some strengthening may be needed, and the electrical installation is covered too.

Structure. Panels and rails add weight, and the wind tries to lift them. On most modern roofs the load is within the capacity of the rafters, but older roofs, roofs with undersized or damaged timbers and roofs already carrying heavy tiles need a check. If strengthening is needed, building control is involved directly, either through your installer or through a building regulations application.

Electrics. In England, adding a new circuit is notifiable work under Part P, the Building Regulations part that covers electrical safety in dwellings (Approved Document P). A solar installation adds a circuit from the inverter to the consumer unit, so it is notifiable. An installer registered with a competent person scheme self-certifies the work and you receive a Building Regulations compliance certificate plus an electrical installation certificate under BS 7671. Wales applies its own edition of Approved Document P, published by the Welsh Government, so ask a Welsh installer which certificate you will receive.

Scotland uses building warrants instead. Councils such as West Lothian say no warrant is needed for solar or PV panels on the roof of a single or two-storey house if the existing roof structure can take the additional load; if it needs strengthening, a warrant is required. Check your council’s guidance, because the rules for taller buildings and for wall-mounted panels differ.

Northern Ireland has its own Building Regulations and building control service run by councils. We found no NI equivalent of the English Part P self-certification route; ask your installer how the electrical work will be certified and keep the BS 7671 certificate.

Installation day: scaffolding, mounting and wiring

Scaffolding usually goes up a day or more before installation and comes down a day or two after. Safe working at height is a legal duty for the installer, so a quote without scaffolding or other edge protection for a two-storey roof is a warning sign, not a saving. Some installers include it; EDF, for example, says its estimate for a typical three-bedroom house includes all installation and scaffolding costs.

On a tiled roof, the installer lifts tiles, fixes roof hooks to the rafters, refits or trims the tiles, and bolts aluminium rails to the hooks. The panels clamp onto the rails. In-roof systems replace a section of tiles with trays and flashing, so the panels sit flush with the roof. Flat roofs take ballasted or mechanically fixed frames, usually tilted at 10 to 15 degrees to reduce wind load and inter-row shading.

The DC cables run through the roof to the inverter, typically in the loft or next to the consumer unit, via a DC isolator. From the inverter an AC cable runs to an AC isolator and a dedicated way in the consumer unit. A generation meter records total output; if you have a smart meter, it records exports separately. Batteries go wherever the manufacturer’s installation rules allow, often a garage, utility room or outside wall.

G98 or G99: telling the network operator

Every grid-connected generator in Great Britain falls under one of two Engineering Recommendations from the Energy Networks Association. MCS summarises the rule for installers:

• G98 covers fully type-tested micro-generators up to and including 16 A per phase, which is about 3.68 kW on a single-phase supply. For solar PV under that limit, the distribution network operator (DNO) must be notified within 28 days of the system being commissioned, using G98 Form B.
• G99 covers anything larger. For solar PV above 16 A per phase, prior permission to connect must be granted before installation, using G99 Form A3.1.

A battery counts towards the limit, so a 3.68 kW solar inverter plus a separate battery inverter can push a home into G99. Installers often handle this with a hybrid inverter that combines both, or with an export limitation scheme agreed with the DNO. Either way, the installer normally fills in and submits the forms.

Your DNO is the company that owns the local wires, not your energy supplier. Great Britain has six DNO groups, and the Energy Networks Association’s postcode tool tells you which one serves your home. Our guide to notifying your DNO about plug-in solar explains the much simpler notice that applies to plug-in kits of up to 800 W.

In Northern Ireland, NIE Networks runs the network and applies its own versions of the connection rules, G98/NI and G99/NI; the Utility Regulator approved Issue 2 of both in March 2026, with implementation recommended from 1 May 2026. The Smart Export Guarantee does not apply there, so export payments depend on what NI suppliers offer voluntarily. Ask the installer which forms apply.

Commissioning, handover and the MCS certificate

Commissioning is the moment the system is switched on and tested. The installer checks insulation resistance and polarity on the DC side, earth fault loop impedance and RCD operation on the AC side, sets the inverter to the UK grid code, and confirms the monitoring app reports output. You should then receive a handover pack containing:

• the MCS certificate, or confirmation that it will follow within 30 calendar days;
• the electrical installation certificate under BS 7671;
• the Building Regulations compliance certificate (England and Wales) or warrant completion paperwork (Scotland) where relevant;
• a copy of the G98 notification or the G99 approval;
• product data sheets, warranties and the installer’s written guarantee;
• the yield estimate and an explanation of the monitoring app;
• instructions for isolating the system in an emergency.

Keep these together. A buyer’s solicitor will ask for them when you sell the house, and an SEG supplier will ask for the MCS certificate.

Getting paid for exports: the Smart Export Guarantee

The Smart Export Guarantee requires licensed electricity suppliers with at least 150,000 domestic customers to offer at least one export tariff, according to Ofgem’s guidance for generators; smaller suppliers may offer one voluntarily. Tariff rates must always be above zero, but suppliers set the rate, the contract length and the other terms, so compare them.

For solar of up to 50 kW you need an MCS certificate or proof that the installation and installer are certified under an equivalent scheme. You also need a meter capable of half-hourly export readings and an export MPAN, which in practice means a working smart meter. You apply directly to the SEG supplier, usually with the MCS certificate, your meter details and proof that you own the system. SEG applies in Great Britain only.

How much SEG pays depends on the tariff and on how much you export. Our guide to plug-in solar and the Smart Export Guarantee shows the arithmetic for a small kit and why plug-in kits normally do not qualify.

How much a UK solar installation costs

The most reliable cost data in Great Britain come from the government’s annual solar PV cost statistics, which draw on installation costs recorded in the MCS database. The edition published on 28 May 2026 covers April 2025 to March 2026. Costs include equipment, installation, connection and VAT where it was charged, but exclude batteries and other additional devices. Northern Ireland is not included.

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Three things stand out. First, costs fell: after adjusting for inflation, the median for systems up to 4 kW dropped 9 percent on the year before, to the lowest on record. Second, retrofits on existing homes cost noticeably more per kW than panels fitted on new builds, because scaffolding, survey and roof work are spread over fewer panels. Third, regional differences are real but smaller than the gap between installers in the same town, which is why several quotes matter more than your postcode.

The statistics measure capacity as declared net capacity, which for most homes equals the inverter rating. The government notes that cost per kW of total installed panel capacity is typically 6 to 12 percent lower. A record 265,682 installations were included in 2025/26, 28 percent more than the year before.

Installer packages as of November 2026

Large installers publish headline prices. These are market observations from their own pages, not quotes for your home:

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Octopus asks for a non-refundable £500 deposit on signing and quotes the Energy Saving Trust as saying a solar system can pay back its cost in 9 to 13 years. Read any package’s inclusions carefully: whether a battery, a bird mesh or an EPC update is included varies.

0 % VAT until 31 March 2027

HMRC zero-rates the installation of solar panels in residential accommodation from 1 May 2023 to 31 March 2027; from 1 April 2027 its guidance says the reduced 5 % rate applies. Since 1 February 2024, batteries installed in homes also qualify, including batteries retrofitted to existing solar. The relief applies to the installer’s supply of materials and labour together. If you buy panels or a kit without installation, the supply is standard-rated at 20 %; that is why plug-in kits from retailers carry full VAT.

Worked example: a 4 kW retrofit in Manchester

This is an example, not a quote. It shows how the figures above combine.

System. Nine panels of 450 W (4.05 kW of panels) on a south-facing roof at about 35 degrees, with a 3.68 kW inverter so the system stays under G98. In the government statistics, declared net capacity is 3.68 kW, which places it in the 0 to 4 kW band.

Cost. At the 2025/26 median of £1,780 per kW: 3.68 × £1,780 ≈ £6,550. At the mean for domestic retrofits, £2,228 per kW: 3.68 × £2,228 ≈ £8,200. A sensible expectation is somewhere between, VAT at 0 %, before any battery.

Yield. PVGIS gives about 886 kWh per kW of panels per year for Manchester at that orientation, with 14 percent system losses. 4.05 × 886 ≈ 3,590 kWh a year.

Value. Assume, for the example, that 40 percent is used in the home and 60 percent exported. At the Ofgem price cap unit rate of 26.32p per kWh for October to December 2026, 1,436 kWh used at home is worth about £378. At an assumed SEG rate of 12p, 2,154 kWh exported earns about £258. Total: about £636 a year.

Payback. £6,550 ÷ £636 ≈ 10 years; £8,200 ÷ £636 ≈ 13 years. That sits inside the 9 to 13 year range Octopus quotes from the Energy Saving Trust. A household at home in the day, or with a battery and a time-of-use tariff, uses more of its own power and shortens the payback; a shaded or east-west roof lengthens it.

Yield by region

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Edinburgh produces about as much as Manchester over a year, because longer summer days offset its darker winter. The south of England produces about 15 percent more than the north. Use these figures to sanity-check an installer’s estimate; a quote that promises far more per kW than PVGIS for your area should explain why.

Step by step: from first call to first export payment

Common mistakes and how to avoid them

• Oversized inverter by default. An inverter above 3.68 kW triggers G99 and can add weeks. Fix: ask whether a G98-sized inverter, or export limitation, would lose meaningful yield on your roof.
• No MCS certificate. A system fitted by a non-MCS electrician may work perfectly but will not normally qualify for SEG. Fix: confirm MCS certification for the specific technology before signing.
• Ignoring the roof’s condition. Fitting panels on a roof that will need retiling in five years means paying twice for removal and scaffolding. Fix: ask the surveyor to comment on the roof covering and fix it first.
• Assuming permitted development on a listed building. It does not apply, and works without consent are a criminal offence. Fix: talk to the conservation officer before you commit.
• Comparing totals instead of contents. A cheap quote without scaffolding, bird mesh or a new consumer unit can end up dearer. Fix: compare itemised quotes.
• Missing the VAT deadline. Installations completed after 31 March 2027 are expected to carry 5 % VAT under current HMRC guidance. Fix: allow for lead times if timing matters.
• Large deposits. Paying most of the price before installation exposes you if the installer fails. Fix: keep deposits modest and confirm the MCS-approved financial protection.

Maintenance after installation

Panels have no moving parts, but the system is not maintenance-free. Inverters typically carry shorter warranties than panels, so budget for a replacement during the system’s life. Check the monitoring app monthly; a sudden drop on a sunny day usually points to a tripped isolator, an inverter fault or new shading. Pigeons nesting under panels are a common nuisance in towns, and bird mesh is easier to fit at installation than later. Our guide to solar panel cleaning and servicing covers what is worth doing and how often.

The plug-in alternative

If a rooftop system is out of reach because you rent, live in a flat, or simply want a smaller first step, a plug-in solar kit of up to 800 W is legal in England, Scotland and Wales since 27 August 2026. It needs no installer, no MCS certificate and no planning permission in most cases in England, but it produces far less, earns no SEG payments in most cases and carries 20 % VAT. Our guides on planning permission for plug-in solar and what plug-in solar saves show where it fits.

Next steps

• Solar panel sizes in the UK: dimensions and how many fit
• Plug-in solar and the Smart Export Guarantee
• Solar panel kits in the UK compared