Size.Solar
350W Solar Panel Production in Durban
A single 350W solar panel in Durban is estimated to generate approximately 527 kWh of electricity per year, averaging 1.45 kWh daily. This represents the actual AC power available for your home after system conversion losses.
Your system settings
Annual bill savings
R20,159
Save about R1,680 per month, capped to the 600 kWh/month use you entered.
Electricity use covered
73%
Produces an average of 440 kWh against 600 kWh of monthly use.
Annual output
5,275 kWh
Daily output
~14 kWh
System size
3.5 kW
Panels needed
14 panels*
Ready for a roof-specific design?
Turn this production estimate into a full project with roof layout, batteries, equipment, and supplier options.
Monthly production breakdown (kWh)
Project-ready estimate
Turn this result into a quote request
Start with 14 panels at 350W, about 4.9 kW, a 600 kWh/month bill target, and 14% modelled system losses. This gives suppliers the first inputs they need before roof layout, inverter limits, and battery choices are refined.
- Starter system
- ~4.9 kW
- Output per panel
- 527 kWh
- Bill value/year
- R2,016
- Weakest month
- Oct
14 panels for a 600 kWh/month home before roof, inverter, and battery constraints.
Estimated annual AC electricity from one 350W panel after modelled system losses.
Annual value at about ZAR 3.82/kWh, capped to the electricity use you can actually offset.
40 kWh from one 350W 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
- Mar
- Lowest month
- Oct
- Solar resource
- 5.4 kWh/m²/day
- Model checks
- 17.2%
49 kWh from one 350W panel
40 kWh from one 350W panel
1965 kWh/m² annual irradiance
Capacity factor, 26.8% performance ratio, 553 kWh DC before conversion
| Jul | Aug | Sep | Oct | Nov | Dec | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 45 kWh | 46 kWh | 42 kWh | 40 kWh | 41 kWh | 45 kWh | 44 kWh | 45 kWh | 49 kWh | 43 kWh | 45 kWh | 43 kWh |
Model basis
The model uses north-facing panels at 30° tilt, true north orientation, and 14% system loss. Typical 600 kWh/month electricity costs are R1,146 - R3,821 (typically R2,293) using 2024-2025 cost data.
Solar production data provided by the PVWatts® API from NLR.