How many solar panels do I actually need? (And why Nairobi beats Germany)
Here is a fact that surprises almost everyone we install for: Germany has more solar panels per person than any large country on earth, and Nairobi gets roughly 60% more sunshine per square metre than Berlin. A panel on a roof in Karen produces in seven months what the same panel in Germany produces in a year. If solar works there, and it does, it works spectacularly here. So the question was never "does solar work in Kenya?" It is "how much of it do I need?" Let's answer that with numbers you can check yourself.
Step one: turn your bill into kilowatt-hours. KPLC charges a little over KES 24 per unit once levies and VAT are added, so a KES 12,000 monthly bill is about 500 units a month, or 16–17 units a day. That single number is the whole design. Everything else follows from it.
Step two: know what one panel gives you. Nairobi averages about 5.5 "peak sun hours" a day, which is the industry's way of saying the sun delivers the equivalent of 5.5 hours at full strength. A 625 W panel therefore makes about 3.4 units on paper, and about 3 units in real life once you allow for dust, heat, cable losses and the inverter. (Yes, heat: panels lose a little output as they get hotter, which is one reason a breezy roof in Limuru can out-produce a still one in Mombasa.)
Step three: divide. 16 units a day ÷ 3 units per panel ≈ 5.5 panels. Round up to six panels to cover your whole daytime use, or eight if you also want to fill a battery for the night. That is exactly why our 5 kW Starter Home package carries eight panels: it is sized for a KES 10,000–15,000 bill, not plucked from the air.
| Monthly KPLC bill | Units per day | 625 W panels (daytime) | Panels with night battery | Our match |
|---|---|---|---|---|
| KES 3,000 | 4 | 2 | 3 | 1.2 kW Starter Kit |
| KES 6,000 | 8 | 3 | 4 | 3 kW Home Kit |
| KES 12,000 | 16 | 6 | 8 | 5 kW Starter Home |
| KES 25,000 | 34 | 12 | 16 | 10 kW packages |
| KES 40,000 | 55 | 19 | 24 | 15 kW Business & Estate |
The part most people get wrong: panels are not the battery. Panels decide how much power you make in the day; the battery decides how long you last at night. A fridge, lights, TV and Wi-Fi draw about 450 W together, so one 5.12 kWh lithium battery runs them for roughly ten hours. If you want the water pump to work at 2 a.m. as well, you want two. Nobody has ever complained that their battery was too big; plenty of people have wished it were.
A curiosity for the roof. The Jinko panels we stock are "bifacial": they have glass on both sides and harvest light bouncing up off the roof or ground. On a pale iron-sheet roof that reflection adds 5–10% for free. It is also why we tilt panels towards the equator, which in Nairobi means almost flat: we sit one degree south of it, so the sun passes nearly straight overhead. Your panels here point at the sky, not at a horizon.
Want your own number? The savings calculator on this page does the arithmetic above from your bill and your night-time loads, and Jua, our online consultant, will happily argue about battery sizes with you. Or send us the bill on WhatsApp and we'll reply with a panel count and a price the same day. Next post: why lithium is cheaper than lead-acid, even though it costs twice as much.