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How many solar panels do I need?

Engr. Amaka Obi, Lead Systems Designer, Crestgreen Energy

M.Sc Renewable Energy (UNN), COREN-registered

Updated · 5 min read

The short answer

Divide your daily energy use in kWh by your region's peak sun hours (4.5 in the South, 5.2 in the Middle Belt, 5.8 in the North) and by 0.75 for real-world losses. That gives the kWp you need; divide by 0.55 for the number of 550W panels. A typical 3-bedroom home in Lagos needs 6–8 panels.

Work out your daily energy

Daily energy is watts × hours for each appliance. A fridge cycles on and off, so count it at about 40% of the day.

Peak sun hours by region

Peak sun hours are the equivalent number of hours at full 1,000W/m² sunshine.

RegionPeak sun hoursExample cities
South4.5Lagos, Port Harcourt, Benin City
Middle Belt5.2Abuja, Jos, Ilorin
North5.8Kano, Kaduna, Maiduguri

Check your roof

A 550W panel is about 2.3m × 1.1m. Ten panels need roughly 26m² of south-facing roof without shade.

Try it with your own appliances

1. What will you run?

  • LED bulb

    10W

    6

  • Ceiling fan

    70W

    2

  • 43" TV

    100W

    1

  • Fridge

    150W · motor

    1

2. Where and how long?

Your recommended system

Inverter
1.0kVA
450W running, 750W surge
Battery
5.12kWh
2.5kWh used at night
Panels
2 × 550W
1.10kWp
Daily energy
3.4kWh
per day
Ask an engineer

Estimates use Crestgreen's design constants (80% diversity above 5 loads, 3× motor surge, 90% depth of discharge). An engineer confirms every design before install.

Packages mentioned in this guide

  • 5kVA

    3–4 bedroom homes

    Family 5kVA

    One 1.5HP AC by day, the whole house by night

    5kVA5.12kWh3.3kWp~10h backup
    ₦3,631,000

    or ₦158,279/month

    Installed price, inc. hardware and installation

  • 3.5kVA

    2–3 bedroom flats

    Home Comfort 3.5kVA

    Freezer, pumping machine and the whole flat

    3.5kVA5.12kWh2.2kWp~10h backup
    ₦3,007,000

    or ₦131,078/month

    Installed price, inc. hardware and installation

Products in this guide

Frequently asked questions

Are 550W panels better than 300W?

Per watt, yes: fewer panels, fewer connections and less roof space. Use smaller panels only where roof space is awkward.

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