UK System Sizes Are Growing

Is the average UK solar system getting bigger?

UK average residential solar system size over time: 2010-2012: 3.0-3.3kW. FIT rules incentivised staying under 4kW (higher rate). 2013-2015: 3.3-3.5kW. Still FIT-influenced sizing. 2016-2019: 3.5-3.8kW. Post-FIT-cut, size optimisation began. 2020-2021: 3.8-4.0kW. FIT gone, optimise for self-consumption. 2022-2023: 4.0-4.5kW. Energy crisis drove demand for maximum generation. 2024-2026: 4.2-4.8kW. EV + heat pump adoption driving larger systems. DRIVERS: (1) Panel efficiency improved (300W→430W per panel) — more kW fits the same roof space. (2) EV ownership adds 1,500-3,000 kWh/yr demand → bigger systems justified. (3) Heat pump adoption adds 4,000-6,000 kWh/yr → 6kW+ systems needed. (4) Cost per kW fell — marginal cost of extra panels is small. (5) No more FIT rate thresholds — no reason to artificially cap at 4kW. PROJECTION: Average system size may reach 5-6kW by 2030 as EV and heat pump become standard. Sources: MCS Data Dashboard (mcscertified.com), BEIS Solar PV deployment statistics (gov.uk), SMMT EV registration data.