Solar panel installation FAQs

The on-roof work for a typical domestic system is one to two days: scaffold up beforehand, mounting and panels on day one, electrical connection and commissioning finishing day one or two. The full journey from accepted quote to switch-on is typically four to eight weeks, driven by scaffold scheduling, kit lead times and (for larger or battery systems) DNO approval. Commercial installations run two to six weeks on the roof inside a longer programme set mainly by the G99 connection process.

Usually not, in England: rooftop panels on most houses are permitted development under Part 14 Class A of the GPDO, and from 27 August 2026 the rules were rewritten (SI 2026/896) - roof-slope panels keep their 0.2 m projection limit, while wall-mounted panels on a house may now project up to 0.4 m (0.2 m where the wall fronts a highway). Flat-roof domestic arrays must stay within 0.6 m of the roof's highest point. Listed buildings always need consent, conservation areas restrict some elevations, and ground-mounted arrays over 9 m2 need an application. Scotland and Wales run their own rules. A proper installer confirms the planning position in writing at survey.

Scaffold is already up. The roof crew sets out the array, lifts tiles to fix anchors into the rafters, fits rails, and lands the panels - photographing fixings as they go. In parallel the electrician runs the DC cabling to the inverter position, fits the inverter, isolators and any battery, and connects into your consumer unit. Then commissioning: insulation-resistance and polarity tests, inverter configuration, generation meter check, and a walkthrough of monitoring. You should end the day with the system generating and a clear list of what paperwork follows.

Five things, and each one matters: the MCS certificate (within about 10 working days - it unlocks Smart Export Guarantee registration), the Electrical Installation Certificate under BS 7671, the DNO notification or G99 approval evidence, the manufacturer warranty registrations (panels typically 25 years performance, inverter 10-12), and the insurance-backed workmanship warranty. Missing paperwork is not a technicality - no MCS certificate means no export payments, and conveyancers increasingly ask for the set at house sale.

Almost always, yes. Working-at-height law makes roof work from ladders indefensible for a crew installing panels, so a scaffold (or occasionally a tower/edge-protection system on easy single-storey roofs) goes up first. It is typically GBP 600-1,200 of a domestic quote - a real cost from a separate trade, and one of the main reasons quotes differ. If a quote is suspiciously cheap, check whether scaffolding is actually in it.

MCS is the UK's installation standards scheme for small-scale renewables. It certifies that the installing company works to the relevant installation standard and that your specific installation is registered. The practical stakes: no MCS certificate, no Smart Export Guarantee payments, and many insurers and lenders expect it. Check a company on the MCS website before you sign - certification is verifiable, claimed 'approval' is not a thing.

They are the two grid-connection routes with your District Network Operator (the company that owns the wires - not your supplier). G98 covers small systems up to 16 A per phase (about 3.68 kW of inverter output): install, then notify within 28 days. G99 covers everything bigger - which includes most solar-plus-battery systems - and requires an application approved BEFORE the system is switched on; the DNO may impose an export limit. The order matters: a G99-scale system fitted before approval can be forced to run export-limited.

Yes, but the fixing detail changes and the labour goes up. Natural slate is brittle - anchors need slate-specific hooks or careful dressing, and a crew that mostly does concrete tile can crack a lot of slate learning. Machine-made clay tiles vary in how they lift. Ask specifically how many slate (or clay) roofs the crew has done and how breakages are handled. In conservation settings an in-roof system at re-roof time is often the better answer.

Following PAS 63100:2024, the sensible homes are a garage, utility room, plant cupboard or a suitable external wall - and NOT lofts, escape routes, or sleeping areas. Batteries want a cool, ventilated location, a solid wall or floor fixing, and clearance around them. If an installer proposes the loft because the cable run is easy, that is a corner being cut against current safety guidance, and worth pushing back on.

Yes, both - and a quote produced without looking at either is guesswork. The loft visit checks rafter condition and size for the fixings and sometimes routes cabling; the consumer-unit check establishes spare ways, earthing arrangement and whether upgrades (surge protection, an isolator position, occasionally a board change) belong in the quote rather than appearing as a surprise on the day.

MCS-reported installation data puts the England average around GBP 1,565-1,590 per kW as of spring 2026. In system terms: a typical 3.5 kWp installation lands about GBP 5,500-8,000 fully installed, a 5-6 kWp system roughly GBP 7,500-11,000, with 0% VAT currently applying to domestic installs (until 31 March 2027). Batteries add roughly GBP 2,500-7,000 depending on capacity and coupling. Regional labour costs move prices 10-15% either side of the average.

Pigeons under arrays are a genuine nuisance issue in many towns. Mesh bird-proofing fitted at install time costs a fraction of a retrofit visit (which needs scaffold again). If your street has a pigeon population, ask for it in the original quote - and check the mesh clips to the panel frames rather than being screwed through anything.

On domestic garages and older commercial buildings with asbestos-cement sheets: fixing panels through asbestos cement is not acceptable practice - drilling it releases fibres and the sheets are too weak to carry point loads safely. The honest options are overclad or replace the roof first (often the right moment to go in-roof or fit a proper liner system), or mount elsewhere - ground mount included. Any pre-2000 commercial building needs its asbestos register checked before survey.

Start from your annual consumption, not your roof. A home using around 3,500-4,500 kWh a year with some daytime occupancy is usually well served by 3.5-5 kWp; add an EV or heat pump and 6-8 kWp with a battery starts to justify itself. With 440-475 W panels now standard, that is fewer panels than older guides suggest - 8 to 14 covers most homes. The design question an installer should ask first is when you use electricity, because self-consumption drives the payback.

Little, but not none. Panels self-clean on most pitched UK roofs; flat and low-pitch arrays benefit from occasional cleaning. The inverter is the component that works hardest - expect to replace it once in the system's life (10-12 year typical lifespan) and factor roughly GBP 800-1,500 when it comes. Monitoring is the real maintenance: a system that quietly stops earns nothing, so the handover should include the app and an explanation of what normal looks like.