Solar Contract
Red Flag Checker

The UK national average for a residential solar installation in 2026 is approximately £1,500–£2,000 per kWp installed. A 4 kWp system should typically cost £6,000–£8,000 including panels, inverter, mounting, scaffolding, electrical work, and MCS registration — all at 0% VAT. Prices below £1,200/kWp should trigger immediate scrutiny: either the quality of components is compromised, labour standards are below par, or costs are being hidden. Prices above £3,000/kWp are also worth questioning with a comparison quote, though London and South East installations can run higher due to scaffolding and labour costs.

The MCS Consumer Code requires a minimum 2-year workmanship warranty, but the industry standard from reputable installers is 10 years. During this period, the installer is responsible for fixing any defects in their work — including roof penetrations, cable routing, mounting system failures, and electrical connections. A workmanship warranty shorter than 5 years is a significant red flag. Always confirm the warranty is backed by insurance (a Consumer Protection Deposit or ring-fenced fund) in case the installer goes out of business during the warranty period.

This is a real and growing risk in the UK market — the solar sector has seen several high-profile insolvencies. If your installer folds before completing work, your deposit is at risk unless you paid by credit card (Section 75 protection for purchases over £100) or the installer held a Consumer Protection Deposit. For warranty claims after installation, the MCS warranty protection scheme provides cover for up to 6 years via the Installation Protection Guarantee. This is why MCS certification matters — it provides a backstop if the original installer disappears.

Absolutely — and this is non-negotiable. Your quote should specify: (1) Panel manufacturer, model name, and wattage; (2) Number of panels and total kWp; (3) Inverter manufacturer and model; (4) Battery brand and model if applicable. A quote that says merely "quality solar panels" or "tier-1 panels" without naming a brand is leaving the door open for component substitution. You should receive the exact datasheet for the panel and inverter before signing, not after. If an installer refuses to name their components, walk away.

Industry best practice is 10–25% upfront deposit, with the balance due on completion. Some installers request a higher deposit to cover panel procurement costs, which is sometimes legitimate for specialist or premium components. Never pay more than 33% upfront without exceptional justification. Always pay the deposit by credit card to access Section 75 protection. Paying the full amount upfront before any work begins is a serious red flag that should cause you to walk away.

No — and it is explicitly prohibited under the MCS Consumer Code. Reputable installers hold their quotes open for at least 14–30 days. Same-day pressure tactics ("this price is only valid today", "my manager has approved a special discount if you sign now") are manipulative and used to prevent you from getting comparison quotes. Under the Consumer Contracts Regulations, you also have a 14-day cooling-off period for any contract signed in your home or away from the trader's business premises. You can cancel without penalty during this period.

A product warranty (typically 10–15 years) covers manufacturing defects — if the panel physically fails, cracks, or deaminates prematurely. A performance (power output) warranty (typically 25 years) guarantees that the panel will produce at least a minimum percentage of its rated output throughout its life — for example, at least 84.8% of original wattage at Year 25. The performance warranty is the more commercially significant one for calculating your return on investment. Both should be included in writing with your installation contract.