In most Kenyan apartment blocks, each unit has its own KPLC meter, and the landlord or management company pays a separate common-area meter for the booster pumps, borehole, lift, corridor and security lights, the gate and CCTV. That bill is usually passed on through the service charge. It is also a good fit for rooftop solar: the roof belongs to the building, and much of the common load can run in daylight.
The example block
A 24-unit block on the small commercial SC3 tariff (about KES 28.82 per kWh all-in in the daytime) uses about 1,500 kWh a month on its common meter:
| Load | Typical share | When it runs |
|---|---|---|
| Water pumps (borehole and booster) | 30% | Can be moved to daytime |
| Lift | 25% | Mornings and evenings mostly |
| Corridor, stair and security lighting | 35% | Mostly at night |
| Gate, intercom, CCTV | 10% | All day and night |
About 45% of this happens in daylight as the block runs today.
Sizing and savings
| As the block runs today | With pumping moved to daytime | |
|---|---|---|
| Daytime use | about 22 kWh a day | about 30 kWh a day |
| Panels (620 W) | 10 | 13 |
| Array | 6.2 kW | 8.1 kW |
| Roof area | about 28 m² | about 36 m² |
| Savings per year | about KES 223,000 | about KES 295,000 |
| Per unit per month | about KES 770 | about KES 1,020 |
The cheapest improvement is free: pump water to the roof tanks during the day instead of at night. That one change raises the share of solar the block can use and adds about KES 70,000 a year in savings.
Lighting and LEDs first
Night lighting is often the largest common load, and solar cannot cover it without a battery. Before sizing solar, replace old fittings with LEDs and fit motion sensors in stairwells and corridors. That can cut the lighting share sharply, at a fraction of the cost of a battery.
Lifts and backup
A lift needs a large inverter and a stable supply, and its motor draws a high current when it starts. Backing up a lift with batteries is possible but expensive. A more common approach is to back up the pumps, security lighting, gate and CCTV on a separate essential circuit, and leave the lift on the grid and the generator if there is one. See our battery backup guide.
Who pays and who benefits
- Owner-occupied or sectional title blocks: the management company or owners' association pays and reduces the service charge.
- Rental blocks: the landlord pays and can either reduce service charges, making units more attractive, or keep the saving as a return on the investment. Being clear with tenants about which builds trust.
- New builds: designing the roof, risers and tank pumping for solar from the start costs far less than retrofitting.
Plan your building
- Enter the common meter's bill in the free solar calculator.
- See on-grid, off-grid or hybrid inverters for which type suits a block with outages.
- For larger developments, request an assessment covering pumping, lighting and backup together.