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How much roof space do I need for solar panels?

As a rough guide, each kilowatt peak of solar PV needs about five square metres of unshaded roof, so a typical four to five kWp domestic array occupies around twenty to twenty five square metres.

Orientation matters less than people assume. South is best, but east–west arrays spread generation across the day and can suit household consumption patterns better, which improves self-consumption.

Shading is the real killer. Even partial shading of one panel can affect a whole string unless optimisers or microinverters are used, so survey chimneys, trees and neighbouring buildings carefully.

Assessment factors

  • Available unshaded area and roof pitch
  • Orientation and any splitting across two slopes
  • Structural capacity of the rafters
  • Inverter location and cable route to the board

Sources

Last reviewed 28 August 2026. General information only — not legal or planning advice.

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