{
 "id": "solar_cost_per_kw_retrofit_4_10kw",
 "name": "Solar PV installed cost on existing homes, 4 to 10 kW systems",
 "category": "costs",
 "value_num": 1651.4,
 "display": "£1,651.40/kW mean, existing homes only",
 "unit": "pounds per kW of total installed capacity (TIC), domestic retrofit installations only (existing homes, not new builds)",
 "period_start": "2025-04-01",
 "period_end": "2026-03-31",
 "period_kind": "data",
 "deadline": null,
 "source_url": "https://www.gov.uk/government/statistics/solar-pv-cost-data",
 "source_org": "DESNZ (from the MCS Installation Database)",
 "checked_at": "2026-09-08",
 "recheck_by": "2027-05-27",
 "history": [
  {
   "period": "2024/25",
   "value_num": 1748.31,
   "display": "£1,748.31/kW mean, existing homes only (67,784 installations)"
  }
 ],
 "public_note": "The middle band on existing homes, and the band more homes now fall into than any other. Bigger arrays cost less per kW than small ones, so a larger system is closer to reach than the small-band figure suggests. Same basis: panels, fitting and connection, no battery. Down on the year before.",
 "next": null,
 "url": "https://hearthsum.co.uk/api/solar_cost_per_kw_retrofit_4_10kw.json"
}