Indicative 4 kWp install in Portsmouth: £6,900–£8,100. Region: South East (×1.04). Annual irradiance: ~1010 kWh/kWp.
What Portsmouth homeowners actually pay
Portsmouth gets some of the best solar yields in the UK thanks to south-coast sunshine — a well-sited 4 kWp array routinely clears 3,900 kWh per year. The city's dense Victorian terraces mean most installs sit on the rear elevation, with prices typically £5,800–£7,400. Modern semis in Cosham, Drayton and Paulsgrove are quicker to install on and often fit a 5 kWp system with battery within £8,500–£11,000.
Local notes for Portsmouth
South-coast irradiance ~975 kWh/kWp/yr — among the highest figures in mainland UK.
Dense Victorian terraces across Southsea and Portsea — many rear-roof installs only.
Old Portsmouth and parts of Southsea sit inside conservation areas with front-elevation restrictions.
DNO is SSEN — G99 sign-off typically 5–7 weeks at current load.
Field notes
Generation ~3,900 kWh/yr from a typical 4 kWp south-facing array.
High coastal irradiance — payback often 7–9 years.
DNO is SSEN — typical G99 sign-off in 5–7 weeks.
Frequently asked questions
Will salt air shorten panel life in Portsmouth?
Modern panels are tested to IEC 61701 for salt-mist resistance, but coastal sites within 500 m of the sea should use marine-grade aluminium mounting and stainless fixings. Most reputable installers spec this by default for PO4 and PO5 postcodes.
What system size suits a typical Southsea terrace?
3–4 kWp on most Southsea and Fratton terraces, with rear-elevation installs the norm. North-Portsmouth semis in Cosham or Drayton often fit 4–5 kWp.