Size.Solar
500W Solar Panel Production in Pretoria
A single 500W solar panel in Pretoria is estimated to generate approximately 856 kWh of electricity per year, averaging 2.35 kWh daily. This represents the actual AC power available for your home after system conversion losses.
Your system settings
Annual bill savings
R26,328
Save about R2,194 per month, capped to the 600 kWh/month use you entered.
Electricity use covered
119%
Produces 1,365 kWh/year above your entered use. Export credits or batteries may add value.
Annual output
8,565 kWh
Daily output
~23 kWh
System size
5.0 kW
Panels needed
9 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 9 panels at 500W, about 4.5 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
- ~4.5 kW
- Output per panel
- 856 kWh
- Bill value/year
- R3,132
- Weakest month
- Dec
9 panels for a 600 kWh/month home before roof, inverter, and battery constraints.
Estimated annual AC electricity from one 500W panel after modelled system losses.
Annual value at about ZAR 3.66/kWh, capped to the electricity use you can actually offset.
65 kWh from one 500W 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
- Aug
- Lowest month
- Dec
- Solar resource
- 6.3 kWh/m²/day
- Model checks
- 19.6%
80 kWh from one 500W panel
65 kWh from one 500W panel
2287 kWh/m² annual irradiance
Capacity factor, 37.4% performance ratio, 897 kWh DC before conversion
| Jul | Aug | Sep | Oct | Nov | Dec | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 76 kWh | 80 kWh | 79 kWh | 79 kWh | 70 kWh | 65 kWh | 67 kWh | 65 kWh | 68 kWh | 68 kWh | 70 kWh | 70 kWh |
Model basis
The model uses north-facing panels at 26° tilt, true north orientation, and 14% system loss. Typical 600 kWh/month electricity costs are R1,038 - R3,912 (typically R2,194) using 2024-2025 cost data.
Solar production data provided by the PVWatts® API from NLR.