Solar in London used to be a hobby for people with big south facing roofs and money to spare. Not anymore. Residential installations currently carry zero per cent VAT through to March 2027, export tariffs have become far more generous, and small businesses are finding that a warehouse roof can quietly cut a serious slice off the electricity bill. The harder question now is who to trust with the job.
The installers below are a mixed bunch on purpose. Some are national brands, some are funded commercial developers, and a few are local firms whose main selling point is that someone answers the phone. Rank matters less than fit, so read the "best for" notes before you read the numbers.
The ten, side by side
Ratings are as listed when this guide was first published and will drift over time, so check the live figure before you book a survey.
| Rank | Installer | Where they work | Main focus | Review score | Accreditations |
|---|---|---|---|---|---|
| 1 | Solar4Good | Nationwide | Homes and businesses | 4.9/5 Trustpilot | MCS, HIES, FMB Award 2026 |
| 2 | Sunsave | London and nationwide | Homes (subscription) | 4.8/5 Trustpilot | MCS, RECC, Which? Trusted |
| 3 | Octopus Energy Solar | England and Wales | Homes | 4.8/5 Trustpilot | MCS |
| 4 | Geo Green Power | London and South East | Homes and businesses | 4.7/5 Google | MCS, Flexi-Orb |
| 5 | Joju Solar | London, Oxford, Sheffield | Homes and businesses | 4.3/5 Trustpilot | MCS, Solar and Storage Awards |
| 6 | The Solar Co. | London and the South | Homes | 4.7/5 Trustpilot | MCS, RECC, Flexi-Orb |
| 7 | Eden Sustainable | London and nationwide | Commercial and industrial | 4.6/5 Google | B Corp, MCS |
| 8 | Efficient Home Energy | London only | Homes | 4.9/5 Trustpilot | MCS, NAPIT |
| 9 | Perfect Sense Energy | London and South East | Commercial | 4.5/5 Google | MCS |
| 10 | Electrosmith | London only | Homes | 4.8/5 Google | MCS, NICEIC, TrustMark |
1. Solar4Good earns the top spot on consistency
Best for: anyone who wants one firm that can do a semi and a factory equally well.
Plenty of installers are good at one thing. Solar4Good is good at both ends of the market, which is rarer than it sounds. Commercial designs start from a client's half hourly consumption data rather than a rough annual guess, and that habit of measuring first shows up in the reviews: a 4.9 on Trustpilot from more than 750 verified reviews, 92 per cent of them five stars, plus 9.7 out of 10 on Checkatrade. It was named FMB Best Solar Installer 2026, an award judged on workmanship rather than marketing. Kit comes from Jinko, Trina, JA Solar and Aiko, with GivEnergy, Fox ESS, Sigenergy and Tesla on the inverter and battery side. Quotes are itemised and panels carry 25 year warranties.
2. Sunsave removes the upfront bill
Best for: households that like the idea of solar but not the lump sum.
Sunsave Plus swaps the purchase for a fixed monthly fee covering panels, battery, monitoring, maintenance, a free battery upgrade, inverter replacement if needed and downtime cover, all under a twenty year guarantee. You won't own the system outright in the usual way, so compare the lifetime cost against a cash purchase. The paperwork is reassuring though: MCS, RECC, TrustMark, NAPIT and Which? Trusted Trader status, with a 96 per cent satisfaction figure from its own customer feedback.
3. Octopus Energy Solar is really a tariff play
Best for: homeowners with a battery who will actually use a smart tariff.
With roughly eight million UK energy customers, Octopus doesn't need to prove it exists. Its edge is the Flux tariff, which at the time of writing paid up to 29p per kWh for electricity exported between 4pm and 7pm, with cheaper overnight import for charging the battery. Octopus suggests that spread can be worth an extra £350 to £450 a year on top of self consumption savings, though tariff rates change and your figure depends on your habits. Installs use JA Solar panels at around 21 per cent efficiency, fitted by in house MCS teams with 25 year warranties.
4. Geo Green Power for serious commercial roofs
Best for: SMEs and larger firms needing bespoke, funded or self funded systems.
Trading since 2010, Geo Green installs between 1.5 and 2 megawatts a month and lists Mercedes-Benz, Smeg, JCB and Kingspan among its clients. A recent rollout for the Jemca dealership group put 272kW across three London area sites, generating about 250,000kWh a year. It has more than seventy staff, and its domestic range now centres on premium SunPower panels with SolarEdge inverters.
5. Joju Solar handles the awkward buildings
Best for: listed buildings, conservation areas, schools and community schemes.
Co-founded in 2006 by Joe Michaels and Oxford renewables lecturer Chris Jardine, Joju describes itself as the UK's longest continuously MCS accredited installer. Its London work includes Grade II listed churches and community buildings, where off the shelf systems simply aren't allowed. Its 4.3 Trustpilot score is the lowest here, which is worth weighing, but for heritage projects with planning headaches it remains one of the few obvious calls.
6. The Solar Co. keeps it personal
Best for: South London and Home Counties homeowners who want things explained properly.
MCS, Flexi-Orb and RECC accredited, The Solar Co. wins on communication. Reviewers repeatedly mention being walked through how their system works and what it should return, which is exactly what a nervous first time buyer needs.
7. Eden Sustainable funds it for you
Best for: businesses without spare capital.
Founded in 2014 and now owned by AMPYR Distributed Energy, Eden is a certified B Corp that offers fully financed commercial installations. Businesses pay nothing upfront and, according to Eden, typically cut electricity costs by 30 to 40 per cent. Retail, logistics, manufacturing and offices all feature in its portfolio.
8. Efficient Home Energy, local and well reviewed
Best for: homeowners who value quick aftercare.
A 4.9 Trustpilot score puts it among the best rated firms in the capital. MCS and NAPIT registration means installs qualify for SEG payments, and being local tends to mean someone can actually come back when something needs looking at.
9. Perfect Sense Energy shows the maths first
Best for: finance directors who need a business case before signing.
Payback periods and self consumption rates are modelled before any design work starts. If your board wants spreadsheets rather than brochures, start here.
10. Electrosmith for accreditation depth
Best for: quality focused homeowners who also want EV charging.
MCS, NICEIC and TrustMark is a heavy stack for a local firm. Electrosmith covers solar, batteries and EV chargers across London, and its reviews keep returning to tidy, professional installation crews.
How to choose without regret
Get at least three quotes, insist on itemised pricing, and confirm MCS certification yourself, since it's what unlocks SEG payments. Then decide what you're really buying: ownership, a subscription, a tariff or a funded commercial deal. For more of our rankings and guides, browse the latest Icon Polls articles.
Do I need a battery?
Not strictly, but tariffs like Octopus Flux only pay off properly if you can store and export at peak times.
Can I put panels on a listed building?
Sometimes, with planning consent. Use a specialist such as Joju Solar rather than a standard installer.
