Size your solar on your town’s real sunshine.

• Sunshine: PVGIS-SARAH3 satellite data for 2005–2023 at Nairobi, panels tilted 10° facing north, 14% system losses. That gives 4.08 kWh per kWp per day on average and 3.07 in July, its lowest month.
• Battery: lithium (LiFePO₄), 90% usable, 90% round-trip efficiency, 95% inverter efficiency.
• “Lower my KPLC bill” sizes the panels for an average day and the battery for one night; KPLC covers the rest, mostly in your town’s weaker months.
• “Run fully off-grid” sizes the panels for your town’s lowest month and the battery for 1.5 days of use.
• Panels are 550 W modules of about 2.6 m² each. The inverter is 25% above your appliances’ combined watts, rounded up to a common size.
• Numbers used: days per month 365 ÷ 12 (30.42); month lengths 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 days; inverter sizes 1, 1.5, 2, 3, 3.6, 5, 6, 8, 10, 12, 15, 20, 25, 30 kW.
• With a bill, savings use your own average rate (bill ÷ units). All savings assume no payment for power sent to the grid.
• With no bill, the rate is a dated estimate: EPRA’s approved base rate for the tariff you pick (home or business) and your band (up to 30, 31 to 100, or over 100 units a month, by your three-month average), plus the charges gazetted on 18 September 2026 for September 2026 meter readings (fuel energy cost, forex adjustment and water levy), plus the six-monthly inflation adjustment, with levies and VAT. Published rules for the levies differ slightly, so we work the rate out both ways and use the middle. We update it by hand each month and hide it once it is about 45 days old.
• This is an estimate. A site visit checks your roof, wiring and loads before any quote.

Source: PVGIS, European Commission Joint Research Centre.