Solar System Size Calculator
Find out exactly what size solar system you need based on your electricity usage. Get personalized recommendations for panels, inverter, and estimated costs.
2,900 monthly searches|Free calculator
Enter Your Usage
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Find this on your Eskom or municipal electricity bill
Quick Reference
- • Small household (1-2 people): 300-500 kWh/month
- • Medium household (3-4 people): 500-800 kWh/month
- • Large household (5+ people): 800-1200 kWh/month
- • With pool pump: Add 200-400 kWh/month
- • With electric geyser: Add 300-500 kWh/month
Your Recommendation
Enter your electricity usage to see your recommendation
Common Appliance Usage
| Appliance | Watts | Typical Hours/Day | Daily kWh |
|---|---|---|---|
| LED Lights (10 bulbs) | 100W | 6h | 0.6 kWh |
| Fridge/Freezer | 150W | 24h | 3.6 kWh |
| TV (55") | 120W | 5h | 0.6 kWh |
| WiFi Router | 10W | 24h | 0.2 kWh |
| Laptop | 65W | 8h | 0.5 kWh |
| Microwave | 1000W | 0.5h | 0.5 kWh |
| Washing Machine | 500W | 1h | 0.5 kWh |
| Air Conditioner | 1500W | 4h | 6.0 kWh |
| Pool Pump | 1100W | 6h | 6.6 kWh |
| Electric Geyser | 2000W | 3h | 6.0 kWh |
System Size Guide
System Sizing FAQs
System size is calculated from your daily kWh usage, divided by average peak sun hours in South Africa (4.5-5.5 hours). We add 20% buffer for system losses and future growth. The result is your recommended inverter size in kW.
For load shedding backup, you need a battery. Size your battery based on which appliances you want to run and for how long. A 5kWh battery typically provides 4-6 hours of essentials backup.
Size for current usage plus 20% growth. If you plan to add an EV, pool pump, or geyser to solar, factor those in now. It is cheaper to install a larger system initially than to upgrade later.
Key factors: roof orientation (north-facing is ideal), shading, panel tilt angle, local weather patterns, panel quality, and inverter efficiency. A site assessment by an installer will give you accurate projections.
Ready for Accurate Quotes?
This calculator gives estimates. For accurate pricing, get quotes from certified installers.