Solar Installation UK 2026: MCS Certification, Grid Connection & What an Installer Should Do

Last reviewed: 17 May 2026 | Chandraketu Tripathi, finance editor

Solar · Installation

Solar PV in the UK in 2026 has moved past the early-adopter stage and into the volume residential market, with around 1.6 million UK homes now generating from rooftop panels, a typical 4kW system installed for roughly 6,500 pounds, and battery storage now fitted on more than half of new installs. The regulatory framework has matured alongside: MCS certification at installer, panel and inverter level governs Smart Export Guarantee eligibility and most insurer recognition, G98 and G99 grid connection codes set out how the install connects to the local Distribution Network Operator, and a temporary 0 percent VAT rating under VAT Notice 708/6 runs until 31 March 2027. This guide walks through MCS, grid connection, 2026 install costs, scaffolding, commissioning paperwork, VAT, the Smart Export Guarantee and the most common install pitfalls.

What MCS certification actually covers

The Microgeneration Certification Scheme (MCS) is the UK standards body for small-scale renewable energy installations. For a residential solar PV install, MCS certification operates at four levels and all four matter for the install to qualify for the Smart Export Guarantee and for most home insurer and mortgage lender recognition.

Installer certification. The installation company must be MCS certified to the relevant scope (solar PV, and battery storage if installing storage). The installer standard is MCS 3005, which sets out the installer competence requirements, the design standards, the commissioning process and the customer documentation that must be handed over. Installer certification is verifiable at mcscertified.com using the installer name or postcode; the search returns the company's certification scopes, status and certificate number.

Panel certification. The PV modules themselves must hold MCS product certification, which references IEC 61215 (design qualification and type approval) and IEC 61730 (safety qualification). Most major panel manufacturers (LONGi, JinkoSolar, Trina Solar, JA Solar, REC, Q CELLS, SunPower) hold MCS certification on their residential ranges; the installer should provide MCS product certificate numbers for the specific panels fitted.

Inverter certification. The inverter must hold MCS certification and must meet G98 or G99 compliance to be permitted to connect to the local distribution network. Common UK-market inverters from SolarEdge, Enphase, Fronius, GoodWe, Solis, GivEnergy and Tesla Powerwall (where used as a hybrid inverter) hold the required certifications.

Battery certification. If a battery is fitted, it must hold MCS product certification under MIS 3012, the battery installation standard. The battery must be installed by an MCS certified installer with battery scope on their certification.

A non-MCS install is technically legal but excludes the homeowner from Smart Export Guarantee payments (every SEG licensee requires the MCS certificate as evidence of generation), is often excluded from home insurer cover for fire or theft, and frequently triggers a query from a buyer's solicitor on resale. The premium for MCS over non-MCS is typically modest (300 pounds to 600 pounds on a 4kW install) and recoverable over the SEG payments alone.

Grid connection: G98 versus G99

Every grid-connected solar install in Great Britain must comply with the Distribution Code engineering recommendations published by the Energy Networks Association. Two recommendations apply to residential PV:

G98 (install then notify). Applies to single-phase generation at or below 3.68kW per phase, which covers most residential single-phase installs up to roughly 4kW. The installer commissions the system, then notifies the local Distribution Network Operator (DNO) within 28 days using the G98 commissioning notification form, submitted through the ENA portal or directly to the DNO. No prior approval is required.

G99 (apply before install). Applies to anything above 3.68kW per phase, three-phase installs, or larger systems with battery storage operating in export mode above the G98 threshold. The installer (or homeowner) submits a G99 application to the local DNO before install. The DNO assesses network capacity at the substation and either accepts the application, imposes export limits, or in rare cases declines. Typical wait time for a G99 acceptance in 2026 is 4 to 12 weeks depending on DNO workload and substation capacity in the area.

The G99 application is not optional and proceeding with a >3.68kW per phase install without G99 acceptance is a breach of the Distribution Code that can result in the DNO disconnecting the install from the network. For homeowners considering a 5kW or 6kW system, factor the G99 wait into the install timeline; some installers will start the G99 application as soon as the contract is signed to compress the elapsed time.

Battery storage interacts with the G98 versus G99 threshold. A hybrid inverter that can export from the battery at high power may push the install over the 3.68kW threshold even if the panel array itself is smaller. Reputable installers configure inverter export limits to keep the install within G98 where possible, or apply for G99 where the customer wants higher export capability.

The 14 UK DNOs operate the ENA Open Networks portal as the single submission point for connection applications and commissioning notifications. UK Power Networks, Northern Powergrid, SP Energy Networks, SSEN, Electricity North West and National Grid Electricity Distribution each cover defined regions. The installer handles the submissions in the normal case; the homeowner should receive copies of both the application and the acceptance or commissioning notification for the records.

2026 UK solar install cost ranges

The figures below are 2026 typical fully installed prices including panels, inverter, mounting, DC and AC cabling, scaffolding, MCS certification, G98 or G99 notification, Building Regulations Part P notification, commissioning paperwork and VAT at the current 0 percent residential rate. Battery storage figures are an additional cost on top of the base install.

3kW system (around 7 to 8 panels, suits one-bedroom or small two-bedroom property). 4,500 pounds to 6,500 pounds installed. Typical annual generation 2,400 to 2,800 kWh in the South of England, 2,000 to 2,400 kWh in Scotland.

4kW system (around 10 panels, the volume choice for UK three-bedroom semis). 5,500 pounds to 8,500 pounds installed. Typical annual generation 3,400 to 3,800 kWh in the South, 2,800 to 3,200 kWh in Scotland. The 4kW size is the historic G98 ceiling and remains the most common UK residential install.

5kW system (around 12 panels, suits larger family homes). 6,800 pounds to 9,500 pounds installed. Requires G99 application because 5kW exceeds the 3.68kW G98 threshold even on a single phase.

6kW system (around 14 to 15 panels, large family home or high-consumption household). 7,500 pounds to 11,000 pounds installed. G99 application required.

Battery storage add-on, 5kWh useable capacity (Tesla Powerwall 3, GivEnergy 5.2, Pylontech US5000 stack). 4,000 pounds to 6,500 pounds fitted at the same time as the PV install. Fitted retroactively after a PV install adds 500 pounds to 1,000 pounds compared with same-day fit due to additional commissioning labour.

Battery storage add-on, 10kWh useable capacity. 6,500 pounds to 10,000 pounds fitted at the same time.

Cost drivers beyond the panel count include roof complexity (pitched slate roofs cost more than concrete tile), the inverter choice (a string inverter from Solis or GoodWe is cheaper than a SolarEdge optimised system or an Enphase microinverter array), the panel tier (Tier 1 brands such as LONGi, JinkoSolar and REC are at the lower end; SunPower and Q CELLS premium ranges add 300 pounds to 800 pounds per kW), and the scaffolding requirement.

Scaffolding and structural survey costs

Scaffolding is required on any pitched-roof install above single-storey eaves height under Health and Safety Executive working-at-height rules. The Work at Height Regulations 2005 apply, and reputable MCS installers will refuse to work without proper scaffolding on a two-storey or three-storey roof. Typical 2026 scaffolding costs are 600 pounds to 1,200 pounds for a standard two-storey UK semi, depending on access, pavement licensing if scaffolding extends over public highway, and the duration of the hire.

Single-storey installs (bungalows, extension roofs) can sometimes be carried out from a tower or with edge protection, dropping the access cost to 150 pounds to 400 pounds. Some installers price scaffolding separately on the quote; others bundle it into the headline install figure. Always check which approach the quote uses, because a quote that excludes scaffolding can appear 800 pounds cheaper than a like-for-like quote that includes it.

Structural survey. The roof must be capable of supporting the additional dead load of the panel array (typically 12 to 15 kg per square metre once mounted) plus the wind uplift loading at the local site exposure category. Most UK pitched timber-rafter roofs built to modern building standards handle this without modification, but properties with older roofs, concrete-tile roofs replaced over original slate without truss upgrade, or any history of roof structural issues should have a structural survey before install. A typical structural survey by a chartered structural engineer is 300 pounds to 600 pounds. Reputable installers carry out a basic structural inspection at the survey visit and decline to install where the roof is unsuitable.

On flat roofs, a ballasted mounting system (concrete weights, no roof penetration) is the usual approach. Ballasted systems add 400 pounds to 900 pounds to the install cost compared with a pitched-roof equivalent because of the weight of ballast and the additional waterproofing checks required.

Commissioning paperwork: MCS, Part P, G98 or G99, SEG MPAN

A compliant solar PV install in 2026 generates five distinct pieces of paperwork at commissioning. The homeowner should receive all five within four to six weeks of install, and retain them for any future property sale, insurance claim or Smart Export Guarantee application.

MCS certificate. Issued by the installer's MCS certification body and uploaded to the MCS Installation Database. The certificate carries the unique MCS Installation Number (MIS number) that the SEG licensee will require to process export payments. Verify the certificate appears in the MCS database lookup at mcscertified.com.

Building Regulations Part P electrical notification. Any new electrical installation in a domestic property is notifiable under Building Regulations Part P. A solar install includes new DC and AC circuits and an interconnection to the consumer unit, all within Part P scope. The installer must self-certify through their Competent Person Scheme (NICEIC, NAPIT, ELECSA or Stroma) and the homeowner receives a Building Regulations compliance certificate within four to six weeks.

G98 commissioning notification or G99 acceptance letter. For G98 installs, the installer submits the commissioning notification to the local DNO within 28 days and the homeowner receives a copy. For G99 installs, the homeowner should have the DNO acceptance letter (received before install) and the post-install commissioning notification. Both attach to the DNO connection file at the property MPAN.

Electrical Installation Certificate (EIC). Issued under BS 7671 (the IET Wiring Regulations) by the installing electrician. Covers the new circuits introduced by the solar install. Required for the Part P self-certification and for any future electrical inspection.

Smart Export Guarantee setup. The homeowner chooses a SEG licensee (Octopus Energy, EDF Energy, OVO Energy, E.ON Next, British Gas and several smaller suppliers all hold SEG licences) and submits the MCS Installation Number, the export MPAN (issued by the DNO at install or already present on a smart meter) and bank details. A SMETS2 smart meter is required to record export readings. The chosen SEG licensee does not have to be the same supplier as the import electricity supplier.

VAT zero-rating under VAT Notice 708/6

Under VAT Notice 708/6 (Energy-saving materials and heating equipment), the supply and installation of certain energy-saving materials in residential property is zero-rated for VAT until 31 March 2027. Solar PV panels, the inverter, battery storage and the associated installation labour all fall within the zero-rated scope when supplied as a single combined supply by the installer.

The zero rate is applied at the point of invoice by the installer; the homeowner does not reclaim anything. A quote that shows VAT at 20 percent on a residential solar install in 2026 is either an installer who has not updated their pricing to the current rules, a non-residential install (commercial, agricultural) which falls outside Notice 708/6, or a mixed-supply situation where part of the work is outside scope. Always confirm the VAT treatment with the installer before signing.

The zero rate covers the materials and the installation labour together. It does not apply to standalone material purchases without installation (a homeowner buying panels directly from a wholesaler and installing themselves does not get the zero rate on the panels), and it does not apply to repairs or maintenance work after the install. The temporary measure was introduced in 2022 and extended through to 31 March 2027 by the most recent Budget; verify the current end date on the gov.uk Notice 708/6 page before relying on the zero rate for an install scheduled close to the end date.

Some peripheral items (roof tile replacement, electrical consumer unit upgrade, scaffolding) may sit in or out of the zero rate depending on whether they are part of the single supply. A reputable installer itemises the supply on the invoice in a way that supports the VAT treatment chosen.

Smart Export Guarantee: choosing a licensee post-install

The Smart Export Guarantee (SEG) is the Ofgem-administered scheme that requires licensed electricity suppliers with 150,000 or more domestic customers to offer a tariff for exported electricity from small-scale renewable generators including solar PV. The SEG replaced the Feed-in Tariff for installs commissioned from 1 January 2020.

SEG rates vary by licensee and tariff. Octopus Energy operates several variable tariffs including Outgoing Fixed at a flat rate and Outgoing Agile at a half-hourly variable rate that tracks the wholesale price. EDF, E.ON Next, OVO and British Gas operate fixed-rate SEG tariffs. Rates in 2026 typically range from 4p per kWh on basic fixed tariffs up to 15p per kWh or more on time-of-use variable tariffs during high-price periods. The chosen SEG licensee does not have to be the import electricity supplier; the homeowner is free to choose any SEG licensee regardless of who supplies the import side.

Three requirements must be met to set up a SEG account: an MCS certified install with a valid MCS certificate (or equivalent Flexi-Orb certification), an export MPAN at the property, and a SMETS2 smart meter capable of recording half-hourly export readings. The export MPAN is issued by the DNO during the G98 or G99 process and appears on the homeowner's electricity bill once the supplier has registered it.

Ofgem publishes the list of SEG licensees and a guide to switching SEG providers at ofgem.gov.uk under Smart Export Guarantee. Switching SEG licensee is similar to switching electricity supplier and takes typically two to four weeks; there is no penalty for switching and homeowners are encouraged to compare rates annually.

Common install pitfalls to watch for

Five pitfalls recur in disputed solar installs reaching the Renewable Energy Consumer Code (RECC) and MCS complaint routes. Each is preventable at quote stage.

Inverter undersizing. A common cost-cutting move is to pair a 4kW panel array with a 3.6kW inverter, clipping generation in peak hours. Modest over-clipping (5 percent or less) is acceptable design practice; significant clipping (more than 10 percent annualised) loses generation the homeowner paid for. The inverter capacity should be at least equal to the panel array DC capacity, ideally 90 to 100 percent of it.

Panel string mismatch. A string inverter requires all panels in a string to face the same way and receive the same shading pattern. Mixing east and west strings on a single MPPT input, or running a string across a shaded chimney, throttles the entire string to the weakest panel. The fix is correct string design at survey or, if shading is unavoidable, a SolarEdge optimised system or an Enphase microinverter array where each panel operates independently.

Missing G98 commissioning notice. The 28-day notification window after commissioning is mandatory under the Distribution Code. Installers who skip the submission leave the homeowner with an unregistered generator, which can block the export MPAN setup and block SEG payments. Ask for a copy of the G98 commissioning notification when the install is signed off.

Scaffolding charged separately. A quote that excludes scaffolding can appear 600 pounds to 1,200 pounds cheaper than a like-for-like quote that includes it. Always confirm whether scaffolding is bundled or separate and whether the figure quoted is fixed or estimated.

Battery oversizing. The optimal battery size for a typical UK three-bedroom semi with a 4kW PV array is 5kWh to 8kWh. Larger batteries (10kWh+) increase capital cost without proportionate self-consumption uplift on a 4kW array, because most generation cycles never fill a 10kWh battery on a sunny day. Match battery size to expected daily generation minus expected daily consumption during sunlight hours, with some headroom for cloudy days.

Frequently asked questions

How much does solar panel installation cost in the UK in 2026?

Typical 2026 UK installed prices are 4,500 pounds to 6,500 pounds for a 3kW system, 5,500 pounds to 8,500 pounds for a 4kW system, 6,800 pounds to 9,500 pounds for a 5kW system and 7,500 pounds to 11,000 pounds for a 6kW system. A 5kWh battery storage add-on fitted at the same time as the PV install runs a further 4,000 pounds to 6,500 pounds; a 10kWh battery 6,500 pounds to 10,000 pounds. All prices include MCS certification, scaffolding, commissioning paperwork and 0 percent VAT under VAT Notice 708/6 until 31 March 2027.

Do I need MCS certification for my solar install?

MCS certification is the gating requirement for Smart Export Guarantee eligibility and for most home insurer and mortgage lender recognition. Every SEG licensee requires the MCS Installation Number as evidence of generation before processing export payments. MCS operates at four levels: the installer must be MCS certified to MCS 3005 with solar PV scope, the panels and inverter must hold MCS product certification, and any battery must hold certification under MIS 3012. Verify installer certification at mcscertified.com using the company name or postcode.

What is the difference between G98 and G99 grid connection?

G98 applies to single-phase residential generation at or below 3.68kW per phase; the installer notifies the Distribution Network Operator within 28 days of commissioning, no prior approval required. G99 applies to anything above 3.68kW per phase or three-phase installs; the installer (or homeowner) submits a G99 application to the local DNO before install and the DNO assesses network capacity, typically taking 4 to 12 weeks. Proceeding with a >3.68kW per phase install without G99 acceptance is a breach of the Distribution Code that can result in disconnection. Both submissions go through the ENA Open Networks portal.

Do solar panels qualify for 0 percent VAT in 2026?

Yes. Under VAT Notice 708/6, the supply and installation of energy-saving materials in residential property is zero-rated for VAT until 31 March 2027. Solar PV panels, the inverter, battery storage and installation labour are all within the zero-rated scope when supplied as a single combined supply by the installer. The zero rate is applied at the point of invoice; the homeowner does not reclaim anything. The temporary measure was introduced in 2022 and extended through to 31 March 2027 in the most recent Budget. Verify the current end date at gov.uk before any install scheduled close to the end date.

How do I claim Smart Export Guarantee payments?

Choose a SEG licensee (Octopus Energy, EDF, E.ON Next, OVO, British Gas and several smaller suppliers all hold SEG licences). The chosen SEG licensee does not have to be the import electricity supplier. Submit the MCS Installation Number, the export MPAN at your property and bank details to the chosen licensee. A SMETS2 smart meter is required to record half-hourly export readings. Rates in 2026 range from around 4p per kWh on basic fixed tariffs to 15p per kWh or more on time-of-use variable tariffs at high-price periods. The Ofgem SEG guide at ofgem.gov.uk lists current licensees and rates.

What paperwork should I receive after a solar install?

Five documents within four to six weeks of commissioning: an MCS certificate carrying the MCS Installation Number and uploaded to the MCS Installation Database; a Building Regulations Part P electrical compliance certificate from the installer's Competent Person Scheme (NICEIC, NAPIT, ELECSA or Stroma); a copy of the G98 commissioning notification submitted to the DNO (or a G99 acceptance letter and commissioning notification for larger installs); an Electrical Installation Certificate under BS 7671 covering the new circuits; and the Smart Export Guarantee account setup confirmation from the chosen SEG licensee. Retain all five for any future property sale, insurance claim or SEG queries.

How we verified this article

Installed price ranges in this article are 2026 typical figures drawn from published MCS certified installer rate cards, the DESNZ Solar PV cost data series and the most recent published Solar Energy UK industry pricing summary. Ranges reflect the spread between London and the South East at the upper end and the rest of the UK at the lower end, and assume a standard pitched-roof install with scaffolding, MCS certification and commissioning paperwork included.

The MCS framework, installer certification scope and product certification standards (MIS 3002 for solar PV, MIS 3012 for battery storage, MCS 3005 for installer standards) reflect the MCS published scheme documents at mcscertified.com. Installer verification, certificate lookup and MCS Installation Database queries operate through the public MCS website.

The G98 and G99 grid connection routes reflect the Distribution Code engineering recommendations published by the Energy Networks Association (ENA) and the ENA Open Networks portal that the 14 UK DNOs use as the single submission point for connection applications. The 3.68kW per phase threshold for G98 versus G99 is the published figure in EREC G98 and EREC G99 as administered by the ENA.

VAT treatment reflects HMRC VAT Notice 708/6 (Energy-saving materials and heating equipment) and the 0 percent residential rating until 31 March 2027 as published at gov.uk. Smart Export Guarantee requirements reflect Ofgem guidance at ofgem.gov.uk. Building Regulations Part P notification reflects Approved Document P (Electrical safety - Dwellings) as published at gov.uk. The IET BS 7671 Wiring Regulations apply to the electrical installation. No figure on this page has been provided by an advertising or sponsored relationship.

Sources

• MCS - find an installer or verify certification
• Ofgem - Smart Export Guarantee (SEG) guidance
• GOV.UK - Approved Document P (Electrical safety in dwellings)
• Energy Networks Association - Open Networks DNO portal
• GOV.UK - VAT Notice 708/6 (Energy-saving materials and heating equipment)
• DESNZ - Solar PV cost data series
• IET - BS 7671 Wiring Regulations
• TrustMark - Find a registered installer