A domestic solar installation is a long-term investment sold on long-term promises, and the contract is where those promises either hold up or fall apart. Buyers tend to focus on the headline payback figure and the size of the system, but the parts that matter years later are the warranties — and there are usually three different ones, each covering something different, often provided by different companies. If the installer goes out of business, a warranty backed only by that installer can become worthless overnight.
What is a Installation and Warranty?
A UK solar panel installation contract covers the supply and fitting of photovoltaic panels, an inverter, and often a battery, plus the connection to your electricity supply. It should set out the system specification, the price and payment schedule, the installation timetable, the expected generation, and the warranties. Typically there are three: a product warranty on the panels and inverter from the manufacturer, a performance warranty guaranteeing a minimum output over time, and a workmanship warranty on the installation itself. A reputable installer should be certified under the Microgeneration Certification Scheme and a member of a consumer code such as RECC.
Red flags to watch for
If the installer ceases trading, an unbacked workmanship warranty disappears. Look for an insurance-backed guarantee that survives the installer's insolvency.
A generation figure based on optimistic assumptions about shading, orientation, and weather is a sales estimate, not a contractual guarantee, unless the contract clearly says so.
A big deposit paid before any work, without insurance-backed deposit protection or staged payments tied to milestones, puts your money at risk if the company fails.
Inverters often fail before panels do. A 25-year panel warranty paired with a short inverter warranty can leave you facing a significant replacement cost mid-life.
Without MCS certification you may be unable to access export payments, and without consumer-code membership you lose an independent route for complaints.
Where a battery or a finance agreement is bundled in, separate cancellation rights and interest costs can be hidden inside a single headline figure.
Your legal rights
The Consumer Rights Act 2015 requires that the installation be carried out with reasonable care and skill, that goods supplied be of satisfactory quality and as described, and gives you remedies including repair, replacement, or a price reduction if they are not. The Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 give you a 14-day cooling-off period for contracts agreed at home or at a distance, though you may have to pay for work you expressly asked to begin within that period. For installations to qualify for the Smart Export Guarantee, the system generally must be certified under the Microgeneration Certification Scheme. Membership of a consumer code such as the Renewable Energy Consumer Code or HIES provides an independent complaints route and, often, insurance-backed warranty and deposit protection.
Questions to ask before you sign
- 1Is the workmanship warranty insurance-backed so it survives if your company stops trading?
- 2Is the stated generation figure a contractual guarantee or a sales estimate, and what assumptions does it rely on?
- 3How long is the inverter warranty compared with the panel warranty, and who replaces a failed inverter?
- 4Is the company MCS certified, and is it a member of RECC or HIES?
- 5How is my deposit protected, and are payments staged against installation milestones?
- 6What exactly is covered by each of the three warranties, and what voids them?
- 7If a battery or finance agreement is included, what are its separate terms and cancellation rights?
Disclaimer: This guide is for educational purposes only and does not constitute legal advice. Contract law varies by jurisdiction and individual circumstances. Always consult a qualified legal professional before making decisions based on this information.