A 4kW solar system in London costs £6,000–£9,500, and the city gets around 1,500 hours of sunshine per year. That's enough to generate roughly 3,400 kWh annually, which covers about half of a typical household's electricity. Compare written quotes and check the installer’s certification before committing.
£6,000–£9,500
Avg. Cost (4kW)
1,500
Sunshine Hours/yr
45%
Homes Below EPC C
£6,000 to £9,500. That's the range for a 4kW system in London, fully installed with scaffolding, which tends to cost more here than anywhere else in the country.
Compare written quotes for the same specification and check certification directly on the MCS Register before appointing an installer.
A south-facing system at that size produces around 3,400 kWh per year in London, enough to cover roughly 75% of an average household's electricity. Combined with a Smart Export Guarantee tariff for the surplus, most installations pay for themselves within 8 to 10 years. For a full breakdown of system sizes and pricing, see our guide to solar panel costs.
Victorian terraces in Hackney. 1930s semis in Croydon. New-builds in Stratford. London's housing stock is all over the place, and each roof type has different installation considerations.
Period properties in conservation areas may need council approval. Flat-roofed extensions, common across inner London, actually work well because adjustable tilt frames let you point panels due south regardless of the building’s orientation.
One thing to watch: scaffolding. London scaffolding costs run higher than the national average, so always confirm your quote includes access equipment before you sign.
If your home already has decent insulation, solar panels are usually the better starting point. They cut your electricity bill from day one and, if you later install a heat pump, the panels offset the increased electricity demand.
A heat pump replaces your gas boiler but increases electricity usage. Fitting solar first means that extra electricity costs you less. Our solar panels vs heat pumps comparison walks through the full decision. Our solar panels vs heat pumps comparison walks through the decision in detail.
Up to £9,000
Boiler Upgrade Scheme
England and Wales. Eligible owners and landlords apply through an MCS-certified installer. The base air-to-water or ground-source grant is £7,500; an extra £1,500 applies to oil/LPG homes without a mains gas connection until March 2027. Air-to-air receives £2,500 and eligible rural off-gas-grid biomass receives £5,000. New fossil-fuel hybrid installations are excluded. Most new builds and social housing are excluded. From 28 April 2026 a valid EPC is no longer required for BUS, though an existing valid certificate number must be provided. Outstanding insulation recommendations are not an eligibility barrier. Funding is confirmed through fiscal year 2029/30 under the Warm Homes Plan, not a guaranteed application deadline.
Learn moreFunding depends on household, property and eligible measures
ECO4
Energy suppliers may fund energy-saving improvements in England, Wales and Scotland. Funding is not guaranteed or a fixed household entitlement. Eligibility depends on tenure, household circumstances, energy rating and eligible measures. Private rented homes generally need EPC E, F or G and landlord permission. Supplier or installer assessment determines the offer and any contribution. Local authority Flex referral is an alternative route, not a funding guarantee. ECO4 ends on 31 December 2026.
Learn moreTwo minutes. No obligation. Find out which government energy grants apply to your property.
Two schemes are worth knowing about. ECO4 can fund a full solar installation if your household receives qualifying benefits. Everyone else gets 0% VAT on domestic solar, which knocks roughly £1,000 to £1,500 off the invoice. Our guide to solar panel grants covers eligibility and how to apply.