Solar Panels for a 4 Bed House

A 4-bed house typically uses 4,000–5,500 kWh of electricity per year. Here is how different system sizes match up:

4kW system (10 panels): - Annual generation: 3,800–4,200 kWh - Covers: 70–100% of electricity usage - Cost: £5,500–£8,000 - Annual savings: £700–£850 - Payback: 8–10 years

5kW system (13 panels): - Annual generation: 4,700–5,200 kWh - Covers: 85–100%+ of electricity usage - Cost: £6,500–£9,500 - Annual savings: £850–£950 - Payback: 8–11 years

6kW system (16 panels): - Annual generation: 5,600–6,200 kWh - Covers: 100%+ of electricity usage - Cost: £8,000–£11,000 - Annual savings: £950–£1,150 - Payback: 8–10 years

Recommendation: Install 5kW if you have the roof space. This covers most 4-bed homes' electricity needs with room for future consumption increases (EV charger, heat pump, home office equipment). If budget allows, go to 6kW — the marginal cost of additional panels is low and the extra generation pays for itself quickly.

Source: Ofgem typical domestic consumption; MCS installer sizing guidance.

4-bed homes tend to have higher electricity consumption than smaller properties:

• More occupants = more appliance usage
• Larger homes = more lighting circuits
• Often have electric showers, dishwashers, tumble dryers
• More likely to have a home office
• More likely to own or plan to buy an EV
• More likely to consider a heat pump in the future

Installing a larger system now future-proofs your home. The incremental cost of adding 3 more panels (from 10 to 13) is approximately £800–£1,200 — but those 3 panels generate £150–£200 extra per year, paying for themselves in 5–7 years.

The mantra: install as much as your roof and budget allow. You will never regret having too much solar.

Source: Energy Saving Trust; Ofgem consumption data.

A battery makes strong financial sense for 4-bed homes because of higher evening consumption:

Without battery (50% self-consumption): - 5kW system savings: £850/year

With 10kWh battery (80% self-consumption): - 5kW system savings: £1,100/year - Additional savings from battery: £250/year - Battery cost: £4,000–£6,000 - Battery payback: 16–24 years

With battery + Octopus Flux tariff: - Export stored energy during 16:00–19:00 peak at 15–24p/kWh - Charge battery from grid overnight at 7.5p/kWh - Additional arbitrage income: £100–£200/year - Effective battery payback: 10–16 years

Recommendation: For a 4-bed home, a battery is worth considering — especially if you are on a time-of-use tariff. The combination of higher self-consumption, peak export income, and overnight cheap charging makes the battery economics work better than for smaller homes.

Source: Energy Saving Trust; Octopus Energy tariff data.

Most 4-bed detached and semi-detached homes have ample roof space for a 4–6kW system. Typical usable area:

4-bed detached: 25–40 m² usable roof space = 14–23 panels capacity 4-bed semi-detached: 18–28 m² usable roof space = 10–16 panels capacity 4-bed end-terrace: 15–22 m² usable roof space = 8–13 panels capacity

Each panel occupies approximately 1.7 m². For a 5kW system (13 panels), you need approximately 22 m² — well within the capacity of most 4-bed homes.

If your south-facing slope is not large enough, consider an east-west split across both slopes — this often allows more total panels.

Source: Standard UK panel dimensions.