In short
- Use an MCS-certified installer. MCS certification is normally needed for export payments and many loans, and MCS sets the rules on estimates, handover and complaints.
- MCS is moving every certified installer onto a redeveloped scheme by 31 March 2027, which includes MCS-approved financial protection lasting at least six years.
- Before you sign, you should receive a generation and self-consumption estimate in the standard MCS format, with the required note that it is guidance only.
- Within 30 days of completion you should have your MCS certificate, any Building Regulations certificate and proof of the grid notification.
- Export payments under the Smart Export Guarantee aren't automatic. You apply to a supplier, and you will usually need an MCS certificate and a smart or export meter.
Why MCS certification matters
MCS, the Microgeneration Certification Scheme, is the UK's quality mark for small-scale renewables. It certifies installers and products, and sets the standards they work to. For solar, that standard is MIS 3002, which covers design, the pre-sale estimate, installation, commissioning and handover.
- Export payments: the Smart Export Guarantee requires the installation to be certified under MCS or an equivalent scheme, and suppliers may ask for your MCS certificate.
- Loans and grants: MCS says certification is a requirement for accessing many government incentives.
- Registration: under MIS 3002, the installer must register your system on the MCS database within 10 working days of commissioning, which generates your MCS certificate.
- Complaints: MCS now manages complaints about certified installations itself and offers free alternative dispute resolution if you and the installer can't agree.
MCS advises checking an installer's certification on its Find an Installer search when you get a quote, before you sign a contract and before installation starts, because certification can lapse. Check they are certified for the technologies you are buying. Batteries have their own MCS standard.
Consumer codes and the redeveloped MCS scheme
For many years, MCS installers have also been members of a consumer code approved by the Chartered Trading Standards Institute, such as the Renewable Energy Consumer Code (RECC) or the Home Insulation and Energy Systems scheme (HIES). These codes set standards for sales, quotations, deposits, contracts and after-sales service.
This is changing. MCS is moving all certified installers onto a redeveloped scheme, with a transition period that runs until 31 March 2027. Under the redeveloped scheme, MCS says:
- Every installer must give customers the MCS Customer Commitment at the first point of contact.
- Every installer must buy an MCS-approved financial protection product on behalf of domestic customers. MCS says these replace the previous insurance-backed guarantee arrangements and give at least six years' cover from installation, including if the installer goes out of business.
- MCS handles complaints in-house and provides free alternative dispute resolution, with findings binding on the installer.
- MCS contacts recipients of certified installations to check how the work went.
MCS has said that installers on the redeveloped scheme no longer need consumer code membership for the Boiler Upgrade Scheme, which covers heat pumps. RECC says approved consumer code membership remains valuable. For a solar installation, ask each installer whether they are on the redeveloped scheme yet, which consumer code they belong to, if any, and exactly which financial protection product your installation will have.
Deposits and protecting your money
MCS's Customer Commitment says an installer will make sure any deposit is reasonable, justified and part of an agreed payment schedule, and tell you how your deposit is protected. It also says they must explain your cancellation rights, including when you have the right to have your deposit returned.
- Pay a modest deposit, and link later payments to stages that are actually complete.
- Ask in writing how the deposit is protected if the installer stops trading before the work is done.
- Paying part of the cost by credit card can give extra protection under the Consumer Credit Act for purchases within its limits.
- If you sign the contract at home, you normally have a 14-day cancellation period under consumer contract rules. Check how the contract handles work started within that period.
- Under the Consumer Rights Act 2015, a service must be carried out with reasonable care and skill.
What a proper survey should cover
The Energy Saving Trust says an assessor will check your roof is safe to hold the panels and design the system around your roof and the space you have. A remote design from satellite images can be a useful start, but MCS requires a specific warning on the estimate if the site was evaluated remotely, because performance may be significantly lower or higher if the real roof differs.
- Roof and structureOrientation, pitch, usable area, covering, condition, and access to the timbers in the loft where possible.
- ShadingTrees, chimneys and nearby buildings, and how the shade moves through the day and the year.
- ElectricsYour consumer unit, earthing, supply type and main fuse, and where the inverter, isolators and any battery will go.
- Your electricity useYour annual use from bills or a smart meter, when you use it, and any plans for an EV or heat pump.
- Access and permissionsScaffolding positions, any highway licence, and planning or listed building issues.
Reading the MCS generation estimate
Under MIS 3002, the installer must give you a performance estimate in a set format before the contract is awarded. It should show:
| Item | What it tells you |
|---|---|
| Installed capacity (kWp) | The size of the system |
| Orientation and inclination | The direction from south and the angle of the panels |
| Postcode region and kWh/kWp (Kk) | The expected output per kWp for your location, pitch and orientation, from MCS tables |
| Shade factor (SF) | 1 means no shading. Below 1 means shading is expected to reduce output |
| Estimated annual output | System size multiplied by Kk and by the shade factor, in kWh |
| Self-consumption | The assumed occupancy type, assumed annual use and expected self-use, with and without a battery if one is quoted |
The estimate must come with an important note saying that solar performance can't be predicted with certainty, that the figure is guidance only for the first year of generation, and that it isn't a promise of performance. Where shading is present and the MCS shading method was used, the installer must add that they believe the result will be within 10% of the actual energy estimate for most systems.
Comparing solar quotes line by line
The Energy Saving Trust recommends getting quotes from at least three MCS-certified installers. MIS 3002 says each quote should come with the performance estimate and the manufacturers' datasheets for the panels and inverter. Compare these points:
- System size in kWp, the number and model of panels, and the inverter type.
- Battery capacity and power, if included, and whether backup power is included.
- Scaffolding, bird mesh, monitoring, any electrical upgrades and the grid notification.
- The generation and self-consumption estimates, and the prices used for any savings figure.
- Product warranties for panels, inverter and battery, and the installer's workmanship warranty and financial protection.
- The payment schedule, deposit protection, start date and how long the price is valid.
- Who will do the work, including any subcontractors, which MCS says must be named.
MCS's Customer Commitment says installers must not use a headline price that misleads you about the likely cost, must state the make, model, power rating and storage capacity of products in the contract, and must give you a written variation and the chance to cancel if a significant change is made after the detailed design.
Handover paperwork you should receive
At handover, MIS 3002 says the installer should explain the system and give you a document pack and a signed declaration that the installation meets the standard. MCS's Customer Commitment adds that you should receive these within 30 calendar days of completion:
- Your MCS certificate.
- Building Regulations compliance certificates, where needed.
- Proof of notification to, or approval from, the network operator, which is UK Power Networks in Kent.
The handover pack should also include a list of key parts, health and safety guidance, a recommended servicing and maintenance schedule, manufacturers' manuals, all relevant warranties, the performance estimate, the recommended interval for the first periodic inspection, and MCS's contact details. Keep everything together for the life of the system. You will need it to claim export payments, make a warranty claim, or sell your home.
Getting paid through the Smart Export Guarantee
The Smart Export Guarantee (SEG) launched on 1 January 2020. Ofgem explains that it requires some electricity suppliers to pay small-scale low-carbon generators, including solar panel owners in Great Britain, for electricity they export to the grid.
- Ofgem's guidance says suppliers with at least 150,000 domestic electricity customers must offer an export tariff. Smaller suppliers can choose to.
- Suppliers set their own rates and contract terms, but Ofgem says rates must always be above zero. Some tariffs are fixed and some vary.
- Payments aren't automatic. You apply to the supplier you choose, and it doesn't have to be the supplier you buy electricity from.
- The installation must be certified under MCS or an equivalent scheme, and payments are based on export meter readings. The Energy Saving Trust says you will usually need a smart meter that records your export.
- You can't be paid for export by two suppliers at once, and you can't receive both Feed-in Tariff export payments and export tariff payments for the same installation.
Some suppliers offer their own export deals outside the scheme, sometimes at better rates if you also buy your electricity from them. The Energy Saving Trust suggests comparing the terms carefully, and notes that Ofgem publishes a list of suppliers offering export tariffs each year.
Smart meters, monitoring and checking your export
To be paid on actual exports, your meter needs to record exported electricity. Ofgem's guidance to suppliers says the export meter should be capable of measuring export at half-hourly intervals, which is what a smart meter does. If you don't have a smart meter, ask your electricity supplier to fit one before or soon after the installation.
- Check that your supplier has registered the meter for export, not just import. A common problem is a meter that records export but isn't set up to send the readings.
- Use the inverter's app or display to see daily and monthly generation, and compare it with the MCS estimate over a full year.
- Keep a note of meter readings when your export tariff starts, and check the first statements carefully.
Looking after your system once it is fitted
Solar panels need little maintenance. The Energy Saving Trust says the main thing is to keep nearby trees trimmed, and that rain will clean panels tilted at 15 degrees or more. MIS 3002 requires your handover documents to include the checks you should carry out yourself, how often, and what to do if something looks wrong.
- Check the monitoring regularly. A sudden drop, an error code or a blank screen is worth reporting promptly.
- Look out for cracked panels, loose cables, pigeons nesting underneath, and scorch marks or damage near isolators.
- Follow the recommended interval for the first periodic inspection in your handover pack.
- Plan for an inverter replacement. The Energy Saving Trust says inverters need replacing after around 12 years, and most have warranties of at least five years that can often be extended.
- Never go on the roof yourself to clean or inspect panels. Use an installer with the right access equipment.
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Sources
- MCS: For consumers: mcscertified.com/consumers/
- MCS: MIS 3002 Solar PV Systems standard, issue 6.0 (March 2026): mcscertified.com/wp-content/uploads/2026/03/MIS-3002_Solar-PV-Systems-V6.0-Final.pdf
- MCS: Customer Commitment, issue 1.1 (September 2026): mcscertified.com/wp-content/uploads/2026/09/MCS-Customer-Commitment_V1.1_2026.pdf
- MCS: How MCS is transforming consumer protection for renewables: mcscertified.com/how-mcs-is-transforming-consumer-protection-for-renewables/
- MCS: DESNZ recognises consumer protections offered by the redeveloped MCS scheme: mcscertified.com/desnz-recognises-strength-of-consumer-protections-offered-by-redeveloped-mcs-as-installer-transition-gathers-pace/
- MCS: Financial protection under the redeveloped installer scheme: mcscertified.com/installers/redeveloped-installer-scheme/financial-protection/
- Renewable Energy Consumer Code (RECC): www.recc.org.uk/
- HIES: Home Insulation and Energy Systems scheme: hies.org.uk/
- Ofgem: Smart Export Guarantee guidance for SEG licensees: www.ofgem.gov.uk/guidance/guidance-seg-licensees
- Ofgem: Feed-in Tariffs, information for generators: www.ofgem.gov.uk/environmental-and-social-schemes/feed-tariffs-fit/generators
- Energy Saving Trust: Rooftop solar panel installation, step-by-step guide (October 2026): energysavingtrust.org.uk/solar-panel-installation/
- Energy Saving Trust: Solar panels, costs, savings and benefits (updated October 2026): energysavingtrust.org.uk/advice/solar-panels/