Will 4kW fit on my roof?

Most 3-bed homes: yes. You need 17-20m² of unobstructed roof. Chimneys, skylights, and hip edges reduce usable space. Your installer measures precisely during the survey.

Roof Space for a 4kW System

By Home Solar Guide Team|Updated 18 March 2026|question

Independently written | Evidence-based | Sources cited

4kW solar system roof space — 10 panels = ~17-20m² = fits on most 3-bed semi or detached roofs.

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How much roof space for 4kW solar?

A 4kW solar system (10 × 400W panels) needs approximately 17-20m² of roof space (including panel spacing and edge setbacks). Each panel: 1.7m × 1.1m = 1.87m². With spacing: ~2m² per panel. Most 3-bed UK homes have 15-22m² of usable roof on one slope — enough for 8-11 panels. Your installer measures exact usable space during the free site survey, accounting for chimneys, skylights, vents, and hips.