Size.Solar

    Solar yield in Nairobi

    Estimated annual solar yield is 1500 kWh per kWp per year. A 400W panel is estimated to produce 600 kWh/year, or 1.64 kWh/day.

    Quick estimate. Uses your location and the time of year. Check your roof, shade, and local weather before using it in a quote.

    Solar Production Calculator
    Estimate solar production in Nairobi
    Adjust the controls for a quick estimate. Check your roof, shade, and local weather before using it in a quote.

    Current estimate

    Annual savings

    KSh313,889

    Use covered

    92%

    Plan 12 panels

    Draw panel areas next. No sign-in needed.

    Your system settings

    400 W
    200WDefault: 400W700W
    panels
    1 panelTotal size: 4.80 kW150 panels
    kWh
    100 kWhTypical: 600 kWh5000 kWh
    14%
    5% (high efficiency)14% (standard)30%
    Your roof orientation

    Choose the direction and slope your panels will actually use. We compare that roof with the ideal north-facing reference for Nairobi using the same weather model.

    0° is flat; 90° is vertical. The ideal reference here is 1°.

    Azimuth simply means direction: 0° north, 90° east, 180° south, and 270° west.

    North is the nearest compass direction.

    Annual bill savings

    KSh313,889

    Average monthly bill value of KSh26,157, based on monthly production and capped to the 600 kWh/month use you entered.

    Electricity use covered

    92%

    Surplus in higher-production months: 607 kWh/year. Export credits or batteries may add value.

    Annual output

    7,200 kWh

    Daily output

    ~20 kWh

    System size

    4.8 kW

    Panels needed

    12 panels*

    Will this system fit your roof?

    Keep these inputs while you outline usable roof space and refine the estimate. Compare installers when the roof plan is ready.

    Plan 12 panels

    Monthly production breakdown (kWh)

    Quote readinessThis estimate is strong enough for early planning. A supplier quote still needs roof space, shading, inverter limits, battery needs, and installation constraints.
    Planning notes* The panel estimate uses average monthly output; winter and summer production vary. Bill savings are capped at your entered use (600 kWh/month) and do not assume export credits.

    Next accuracy check

    Check this estimate against your roof

    The figures below are an example starting point for Nairobi: 12 panels at 400W, about 4.8 kW, and a 600 kWh/month electricity-use target. Review your current panel wattage, panel count, and electricity use in the calculator above before opening the roof planner or comparing installers.

    Review current inputsBrowse installers
    Example system
    ~4.8 kW

    12 panels for a 600 kWh/month home before roof, inverter, and battery constraints.

    Output per panel
    600 kWh

    Estimated annual AC electricity from one 400W panel after modelled system losses.

    Bill value/year
    KSh313,889

    Annual value at about KES 47.62/kWh, capped to the electricity use you can actually offset.

    Weakest month
    Jun

    35 kWh from one 400W panel; check this month before sizing essential loads.

    Roof fit

    Confirm usable roof planes, shading, inverter limits, and battery needs before accepting a final layout.

    Bill fit

    Adjust panel count and monthly use above so savings are capped to electricity you can offset.

    Quote check

    Ask suppliers to show winter output, assumed losses, and any export-credit value separately.

    Production evidenceShow monthly output and model assumptionsOpen this when checking winter production, irradiance, losses, or the source assumptions behind the quote handoff.

    Monthly model

    Monthly output and winter risk

    The calculator is useful when it shows the weak months, not just a flattering annual number. Use the table to check whether winter output still supports the loads you care about.

    Best month
    Dec

    65 kWh from one 400W panel

    Lowest month
    Jun

    35 kWh from one 400W panel

    Solar resource
    5.0 kWh/m²/day

    1829 kWh/m² annual irradiance

    Model checks
    17.1%

    Capacity factor, 82.0% performance ratio, 652 kWh DC before conversion

    JulAugSepOctNovDecJanFebMarAprMayJun
    37 kWh42 kWh50 kWh56 kWh61 kWh65 kWh61 kWh56 kWh52 kWh46 kWh39 kWh35 kWh

    Model basis

    The model uses north-facing panels at 1° tilt, true north orientation, and 14% system loss. Typical 600 kWh/month electricity costs are KSh24,700 - KSh33,000 (typically KSh28,570) using 2024-2025 cost data.

    These monthly figures are a quick estimate. Check your roof, shade, and local weather before using them in a quote.

    Change the modeled city