Most people compare solar quotes on the total price, or at best the price per kW. Both can mislead. Two quotes for the same need can differ in system size, equipment quality, what is included and what happens when something fails. The fair comparison is what each system costs per kWh it will deliver, for equipment you know, with nothing missing from the price.
A worked example
Suppose a home or small office uses about 19 kWh a day in daylight and asks three suppliers to quote:
| Quote A | Quote B | Quote C | |
|---|---|---|---|
| Array | 5.0 kW | 6.2 kW (10 x 620 W) | 5.0 kW |
| Quoted price | KES 520,000 | KES 560,000 | KES 420,000 |
| Price per kW | KES 104,000 | KES 90,300 | KES 84,000 |
| Exclusions | None | None | Mounting, DC cabling and protection (about KES 75,000) |
| Real price | KES 520,000 | KES 560,000 | about KES 495,000 |
Quote C looks cheapest by KES 100,000, but once the excluded items are added it is only KES 25,000 below Quote A. Quote B looks dearest but has the lowest price per kW.
Step 1: put every quote on cost per kWh
Across Kenya, each kW of panels produces about 1,400 kWh a year. Allowing for panels losing about 0.5% of their output each year, a kW produces roughly 33,000 kWh over 25 years.
| Quote A | Quote B | Quote C (real price) | |
|---|---|---|---|
| Output in the first year | about 7,000 kWh | about 8,700 kWh | about 7,000 kWh |
| Output over 25 years | about 165,000 kWh | about 204,000 kWh | about 165,000 kWh |
| Cost per kWh produced | KES 3.16 | KES 2.74 | KES 3.01 |
| Including one inverter replacement (example KES 100,000) | KES 3.77 | KES 3.23 | KES 3.62 |
All three are far below the KES 28.30 a domestic DC2 unit costs from KPLC, which is why solar pays. But the figures only hold if you use the output. Quote B produces about 24 kWh a day against a 19 kWh daytime need. Unless you add daytime loads or a battery, the extra panels mostly produce energy you cannot use, and the real cost per useful kWh is higher than the table shows. Size first, then compare.
Step 2: insist on exact models
A quote that says "5 kW inverter, 620 W panels, lithium battery" cannot be checked. Ask for:
- The manufacturer and model number of the panels, inverter and battery, with datasheets.
- The battery's usable capacity in kWh, not just the nominal figure, and its rated cycle life.
- The inverter's continuous and surge ratings, so it can start your pumps and fridges.
- The mounting system, cable sizes and protection devices (DC isolators, surge protection, earthing).
With exact models you can compare like for like and check that the parts work together.
Step 3: read the exclusions
Common items left out of cheaper quotes include mounting structures, cabling, trenching, the changeover or distribution board work, transport to site, commissioning and the first service. Ask each supplier to price the same complete scope, or add the missing items yourself before comparing.
Step 4: compare warranties and support
| What to ask | Why it matters |
|---|---|
| Panel product and performance warranty | Product warranty covers defects; performance warranty covers output loss over 25 years or more. |
| Inverter warranty, and who handles claims | The inverter is the part most likely to fail; a claim through an overseas maker can take months. |
| Battery warranty in years and cycles or throughput | Both limits matter; the battery may hit its cycle limit before its years. |
| Workmanship warranty | Covers the installation itself: roof leaks, loose connections, poor earthing. |
| Response time for faults | A dead system for three weeks loses a month of savings. |
Step 5: check the installer
Solar PV installers in Kenya must hold a licence from the Energy and Petroleum Regulatory Authority (EPRA). Ask for the licence number and check it, ask for two or three recent installations you can visit, and get the design (array layout, string sizing and single-line diagram) in writing before you pay a deposit.
Make the comparison easier
- Size the system for your needs first with the free solar calculator, so every supplier quotes against the same target.
- Solar by county gives the monthly sun hours for your area, which change the output per kW.
- StimaPulse records structured requirements and supplier responses side by side; see how sizing works or request an assessment. Our article on solar payback shows how to turn the winning quote into an honest payback figure.