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 the work? Check what it usually costs, or work out your own estimate. The free quote form is at the top of this page.
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.