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Size Your Solar System
In Under 60 Seconds

Know exactly what panels, inverter & battery you need — before talking to any installer. Used worldwide.

✅ Surge-aware inverter sizing 🔋 Battery backup calculator 📊 Real sun hour data · 40+ countries 💰 Savings & payback estimator
📍Location & Setup
Country
System Type
☀️ Peak sun hours in your area ?Average daily hours of full-intensity sunlight. Higher = more solar generation.
6.2 hrs/day
🔌Your Appliances
4 appliances
⚡ Motor loads (AC, fridge, pumps) draw 3–6× surge current at startup. SunWatt accounts for this in inverter sizing.
🔆Panel Wattage
Panel size to calculate with
⚙️Your Solar Setup
No. of Panels
Panel Wattage (W)
Inverter (kW)
Array Size— kWp
Daily Generation— kWh/day
Monthly Generation— kWh/mo
Panel : Inverter Ratio—
RECOMMENDED SYSTEM
—
kW
Add appliances to see your recommendation
0%Load vs Inverter100%
Total Running Load—
Daily Usage—
Panels Needed—
Array Size—
⚡Recommended Inverter
Minimum inverter size
— kW
—
⚡
Surge capacity needed—
Inverter type—
🔋Battery Backup
Battery Capacity
Night Load (W)
—
hours of backup power
📈Monthly Generation Estimate
💰Estimated Savings
—
Monthly saving
—
Annual saving
—
kg CO₂/yr avoided
—
Payback estimate
Based on local tariffs & avg install costs. Indicative only.
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Common Solar Questions

Everything you need to know before going solar.

How many solar panels do I need for my home?
It depends on your daily electricity usage and local sunlight. A typical home uses 20–30 kWh/day and needs a 5–10 kW system with 10–20 panels. Use SunWatt's Simple Mode to get an exact number based on your actual appliances and country.
What inverter size do I need for solar?
Your inverter must handle your total running load plus the startup surge of your biggest motor (AC, pump, fridge). A good rule: inverter kW ≥ (running watts + largest surge) ÷ 1000, with 10% headroom. SunWatt calculates this automatically.
What is the solar panel to inverter ratio?
This is your DC array size (kWp) divided by inverter AC capacity (kW). Industry standard is 1.0:1 to 1.3:1. Going above 1.3 risks power clipping and can void inverter warranties. SunWatt warns you when you're out of range.
How accurate are SunWatt's calculations?
We use real country-specific peak sun hour data and an 80% system efficiency factor (accounting for wiring loss, temperature derating, dust, and inverter losses). Results are typically within 10–15% of a professional solar assessment.
How much does a solar system cost?
Varies widely by country. In the US a 6kW system costs $10,000–$18,000 before incentives. In Pakistan or India it's $4,000–$7,000. In UAE/Saudi roughly $6,000–$10,000. Our savings card estimates payback using local electricity tariffs.
Do I need a battery for solar?
Batteries are optional but valuable for backup power during outages or to use solar energy at night. For most homes, a 10–20 kWh battery provides 8–16 hours of essential loads. Use SunWatt's battery calculator above to find what you need.