DIY solar installation guide

Is DIY solar installation right for you?

Fitting your own panels can cut 30–50% off a typical UK installer quote, because you're paying only for parts, not labour. That saving is real, but it assumes you can safely work at height on a roof, run and terminate DC cable to spec, and are comfortable reading a wiring diagram. If any of that is a stretch, the money saved isn't worth the risk — a fall from a domestic roof is the single biggest cause of serious DIY solar injuries in the UK. Rate yourself honestly against three things before you order parts: roof access (scaffold tower or existing loft hatch access to the eaves), electrical competency (comfortable with AC isolation and consumer unit work, even if you're not doing the final connection yourself), and time (most DIY installs take two to four weekends spread over several weeks, not one).

DIY vs professional installation: what you actually save

A professionally installed 4kW system in the UK typically costs £5,000–£7,000 including labour, scaffolding, and certification. Buying the same panels, inverter, and mounting kit yourself usually runs £2,500–£3,800 — the labour and margin an installer adds is the difference. What DIY doesn't save you: you still need a qualified electrician for the consumer unit connection (most DIYers aren't competent to self-certify this under Part P), and you'll pay for that visit separately, typically £150–£300. Roof work — mounting rails and panels — is the part DIY installers do themselves and where most of the saving comes from.

Legal and regulatory requirements for DIY solar in the UK

DIY solar installation is legal in England, Wales, Scotland, and Northern Ireland, but three separate approvals apply and missing any of them can leave you unable to claim export payments or invalidate your home insurance. For the full breakdown of exactly what you're allowed to fit yourself versus what needs a qualified person, see our DIY solar installation legal guide. The short version:

• Building Regulations (Part P): the final connection to your consumer unit is notifiable electrical work. Unless you use a registered electrician who can self-certify, you must notify your local authority building control and pay for an inspection — see gov.uk's Building Regulations approval overview.
• DNO notification (G98/G99): your Distribution Network Operator must be notified before or shortly after a grid-tied system is energised — G98 for small systems up to 16A per phase (roughly 3.68kW single-phase), G99 for anything larger. Skipping this step is a breach of your electricity supply terms, not just a formality.
• MCS certification for SEG payments: Smart Export Guarantee payments for exported electricity require an MCS-certified installation. A fully self-installed system usually can't be MCS-certified after the fact, because certification covers the installer, not just the equipment — see our Smart Export Guarantee guide. If SEG income matters to your payback numbers, get an MCS-registered installer to handle the connection and sign-off rather than doing the whole job yourself.

Warranty implications of self-installing

Manufacturer product warranties on panels and inverters (typically 12–25 years) are unaffected by who fits them — they cover defects in the equipment itself. What you lose is any installation warranty an installer would normally provide (workmanship cover on leaks, mounting, and wiring, usually 2–10 years), and some panel manufacturers require MCS-certified installation to honour the full warranty term, so check the small print before you buy. Roof penetrations from mounting rails can also affect your roof warranty if the property is still covered — check with your roofer or builder first.