How to Plan a Solar Panel Installation Step by Step (2026 UK)
A well-planned solar install is decided in the planning stage. This 7-step guide takes you from assessing your roof and sizing the system to choosing an MCS-certified installer, handling DNO notification and registering a Smart Export Guarantee tariff so you get paid for surplus power.
Planning a Solar Panel Installation: Where to Start
A well-planned solar installation starts long before the panels arrive. The biggest decisions — system size, whether to add a battery, and choosing an MCS-certified installer — are made in the planning stage and determine how much you save and how quickly the system pays back.
A typical 4 kWp system on a UK home costs around £5,000–£7,000 in 2026, with a battery adding £2,000–£5,000. This step-by-step guide takes you from assessing your roof to registering your export tariff so you get paid for surplus power.
Solar Planning at a Glance 2026
| Factor | Ideal / Typical | Notes |
|---|---|---|
| Roof orientation | South (E/W = 80–85%) | Avoid north-facing pitches |
| Roof pitch | 30–40° | Flat roofs need mounting frames |
| System size | 3.5–4 kWp (typical home) | Match to your annual kWh use |
| Typical cost (4 kWp) | £5,000–£7,000 | Battery adds £2,000–£5,000 |
| Certification | MCS required | Needed for SEG export payments |
| DNO process | G98 (≤3.68 kW) / G99 | G99 needs prior approval |
Figures are 2026 UK averages; your quote depends on roof, equipment and installer.
A Note on Equipment and Warranties
Panels typically carry 25-year performance warranties and inverters 5–12 years (often extendable). Choose established, well-supported brands and confirm warranty terms in writing — a warranty is only as good as the company behind it. With several battery manufacturers having faced financial difficulty recently, prioritise installers who offer strong, independently-backed warranties and proven, currently-supported equipment.
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Get My Free Quotes →Solar Installation Planning FAQ · 2026
Size to your annual electricity use and roof space. A typical 3-bed UK home using ~3,500–4,000 kWh/year suits a 3.5–4 kWp array (about 9–10 panels). Bigger isn't always better — oversizing without a battery or EV just exports cheap power. A good installer sizes the system to your consumption pattern.
South is ideal but not essential. South-facing roofs at a 30–40° pitch give the best yield; east/west roofs typically produce 80–85% of a south array and can suit homes that use power morning and evening. North-facing pitches are rarely worthwhile. Shading from chimneys, trees or neighbouring buildings matters more than a few degrees of orientation.
For most homes, roof-mounted solar panels are Permitted Development provided they don't protrude more than 200mm and aren't on a listed building. Conservation areas and listed buildings have restrictions — check with your local planning authority. Ground-mounted arrays above a certain size may need permission.
Yes. Your MCS-certified installer notifies your Distribution Network Operator (DNO). Systems up to 3.68 kW per phase use a simple G98 'connect and notify' process; larger systems need G99 approval before installation, which can take a few weeks — factor this into your timeline.
The physical install on a typical home takes 1–2 days once scaffolding is up. The full journey — survey, quotes, DNO notification, scheduling and commissioning — usually takes 4–8 weeks. Registering your Smart Export Guarantee (SEG) tariff afterwards lets you get paid for exported power.