How long does a UK solar installation actually take?

The "install day" is just the visible part. A UK solar installation usually spans 4–10 weeks from first quote to commissioning, with the actual on-roof work taking 1–3 days. This guide walks through the whole sequence so you know what to expect — and where the delays usually come from.

The timeline in one sentence

For a typical UK domestic install with no listed-building or DNO complications:

• Quote and contract: 1–2 weeks
• Survey: within 1–2 weeks of contract
• DNO approval (if needed): 2–6 weeks
• Install day: 1–3 days
• Certification and handover: within 1 week of install

Total: usually 4–10 weeks from accepting a quote to having a generating system.

Stage 1: Quote and contract (1–2 weeks)

You contact installers, get quotes, compare them. Reputable installers will visit (or do a satellite-based desktop survey) before quoting. Watch for:

• Quotes that come back the same day with no site visit — usually generic figures, often need adjusting later.
• "Limited-time discount" pressure — solar quotes don't expire that fast in 2026.
• Vague line items — see the eight questions to ask before you sign a quote.

Once you accept, you'll typically pay a deposit (10–25% under RECC rules, more without). Reputable installers don't ask for full upfront payment.

Stage 2: Survey (1–2 weeks after contract)

The survey is the critical step that catches surprises. A surveyor (sometimes the lead installer themselves) checks:

• Roof structure and condition
• Available area for panels and the layout that fits
• Shading at different times of day
• Electrical setup — consumer unit, fuse box, inverter location
• Cable routes and access for installation

If the survey finds issues (asbestos in older roofs, inadequate consumer unit, structural concerns), the installer comes back with revised costs. Most surveys don't surprise — but the few that do are the reason a paper-only quote can't be the final word.

Stage 3: DNO approval (2–6 weeks if needed)

The DNO is the regional company that owns the local power lines. Before you can connect a solar system to the grid, the DNO must know about it:

• Systems up to 3.68 kWp: "Notify after install" (G98). No wait.
• Systems above 3.68 kWp: Apply before install (G99). The DNO has 11 working days to respond, and sometimes asks for network upgrades that can extend further.

For a typical domestic install (4–6 kWp), DNO approval takes 2–4 weeks but can be longer in busy areas. Reputable installers handle this for you and bake the wait into their delivery date. Confirm they're managing it before you commit.

Stage 4: Install day (1–3 days)

The visible part. Roughly:

Day 1 (most installs)

• Scaffolding goes up early morning
• Mounting rails are fixed to the roof
• Panels are lifted onto the roof and bolted into place
• Cabling is routed back to the inverter location
• Inverter and isolators are mounted
• Generation meter is installed

Expect the team to be on site 6–8 hours, with 2–3 people on the roof and one inside doing electrical work. Most installs finish in one day.

Day 2 (sometimes)

• Final wiring and connection to the consumer unit
• Commissioning — turning the system on, running the first generation tests
• App / monitoring setup
• Walk-through of how the system works
• Scaffolding comes down

For larger systems (8+ kWp), or installs with battery storage, day 2 is normal. For complex installs (3-storey terraces, listed building flashing details, integrated panels) day 3 is occasional.

Stage 5: Certification and handover (within 1 week)

The system is generating from day 1, but the paperwork takes a few extra days:

• MCS certification. The installer files the install with MCS within 10 days. You get a copy emailed.
• DNO confirmation. The installer notifies the DNO that the system is now connected (G98 systems) or confirms the install matches the approved plan (G99).
• Warranty registration. Panel and inverter manufacturers are registered, locking in your warranty.
• Handover pack. Installer sends you the install certificate, electrical certificate, MCS certificate, warranty documents, and the monitoring app login.

This pack is your proof of certification — keep it. You'll need the MCS certificate to sign up to a Smart Export Guarantee tariff.

What happens after handover

A working UK solar install needs very little ongoing attention:

• Year 1: Watch the monitoring app to confirm output is in the expected range. Most apps flag faults automatically.
• Year 1–10: Panels are largely maintenance-free. UK rain handles cleaning in most cases. A visual inspection annually is enough.
• Year 10–12: Inverter likely needs replacing. Plan for £700–£1,200 if it's not still under warranty.
• Year 25+: Panels still generating at 80%+ of original capacity. Your call whether to keep them, replace them, or sell up.

Where delays usually come from

In rough order of how often they trip up timelines:

1. DNO approval queues. Sometimes 6–8 weeks instead of the 11 working days minimum, especially in dense urban areas.
2. Scaffolding availability. Particularly in summer when most installs happen.
3. Listed-building paperwork. Conservation areas and listed buildings need planning input — adds 2–8 weeks if applicable.
4. Roof issues found at survey. Slipped tiles, rotten battens, or a roof needing replacement — adds time and cost.
5. Consumer unit upgrades. Some older homes need a new fuse box first.

Related

• Eight questions to ask before you sign a solar quote
• How much do solar panels cost in the UK?
• Find listed installers covering your postcode
• Smart Export Guarantee explained