UK residential PV passed 1.4 million installs by end of 2024 and now grows at ~150,000 installations per year. The market shifted decisively post-2019 from feed-in-tariff-driven economics to self-consumption + SEG (Smart Export Guarantee) payments. Tariff volatility during 2022-2023 (peaks at 30+ p/kWh) accelerated installs sharply; with retail tariffs settling around 28 p/kWh in 2025, payback has stabilised at 8-12 years for typical 4-6 kWp residential rooftop without battery, falling to 6-8 with battery and high self-consumption.
The MCS (Microgeneration Certification Scheme) is the gatekeeper. Without an MCS-certified installer's signoff, you cannot claim SEG payments and most major suppliers will refuse to enrol the system. MCS certification is rigorous (annual audits, technical training, financial liability insurance) and adds typically £500-1,500 to install cost vs an unaccredited installer. For most residential customers, the SEG payment over 15-20 years more than offsets this premium.
Cost benchmarks: turnkey MCS-certified install runs £1,400-1,800/kWp for typical 4-6 kWp residential, with battery adding £600-900/kWh of usable storage. The 0% VAT rate (in force April 2022, extended through March 2027 by HMRC) saves 20% versus the standard rate; non-MCS DIY installs do not qualify for 0% VAT.
Permits and grid connection
- Permitted Development applies to most residential rooftop PV — no planning permission needed if the array is below the highest point of the roof (excluding chimneys), within 200mm of the roof plane, and not on a listed building.
- Listed buildings (Grade I, II*, II) need Listed Building Consent — separate process, can take 8-12 weeks.
- Conservation Areas: PV is permitted only on roofs not visible from the highway — practical effect: street-facing slopes blocked, rear-facing OK.
- G98 / G99 grid connection: G98 covers single-phase < 16 A (most residential, no DNO approval needed pre-install — only post-commissioning notification within 28 days). G99 for three-phase or > 16 A requires DNO pre-approval.
- Building Regulations Part P applies — electrical work must be by a registered electrician or self-certified by an MCS installer.
Incentives and tariffs
- 0% VAT on residential PV + battery + EV chargepoint installation (April 2022 - March 2027 per HMRC). Includes panels, inverters, mounting, labour.
- Smart Export Guarantee (SEG) payments — every electricity supplier with > 150,000 customers must offer at least one SEG export tariff. Octopus Outgoing pays 15p/kWh fixed (best in market 2025); EDF Export+ pays 5.6p/kWh; British Gas Export pays 5p/kWh. Suppliers can switch tariffs.
- Smart Export Guarantee requires MCS certification on the installation — DIY non-MCS installs cannot claim SEG.
- Welsh Government Nest scheme: free or means-tested PV + battery for low-income households (Wales only). Scotland: Home Energy Scotland loans (interest-free up to £6,000 for PV).
- ECO4 (Energy Company Obligation) covers PV + battery for low-income households in England — administered by major energy suppliers, eligibility means-tested.
FAQ — United Kingdom
Is the FIT (Feed-In Tariff) still available?
No — FIT closed to new applications on 31 March 2019. Existing FIT contracts continue paying for their original 20- or 25-year duration. New installs must use SEG instead, which pays per-kWh exported but at much lower rates than legacy FIT.
Why does MCS certification matter so much?
Two reasons: (1) it's required for SEG export payments, and (2) it's required for the 0% VAT rate. Skipping MCS saves £500-1,500 upfront but loses 20% VAT savings (~£1,500-2,500 on a typical 5 kWp install) plus 15-20 years of SEG income. The math almost always favours MCS.
Which SEG tariff is best?
Octopus Outgoing has paid 15p/kWh fixed since launch and remains market-leading in 2025. To enrol you typically need to also be an Octopus electricity customer, but the rate gap (15p vs 5-6p elsewhere) usually justifies the switch for any household exporting > 1000 kWh/year.
Do I need three-phase power for residential PV?
Single-phase is fine for systems up to ~3.68 kW AC inverter output (16 A). Above that you either upgrade to three-phase (typically £600-2000 paid to the DNO), accept G99 pre-approval delays, or limit the inverter via firmware. Most 4-6 kWp residential installs sit at 3.68 kW inverter.
Live data sourced from Eurostat (residential tariff), PVGIS v5.3 (irradiance), ECB (FX). Editorial regulatory content verified against official sources on 2026-05-04. Detailed balcony-PV regulations for United Kingdom live on the balcony-solar country guide.