Stop Guessing — Here Is How to Size Your Solar System
Every homeowner asks: "How many panels do I need?" The answer depends on your electricity usage, roof space, panel efficiency, and local sunlight. Let us break it down.
Step 1: Know Your Annual Usage
Check your bill for annual kWh consumption. US average: ~10,500 kWh. Europe: 3,000–5,000 kWh. Middle East with heavy AC: higher.
Step 2: Peak Sun Hours
Not daylight — equivalent hours of full 1,000 W/m² sunlight daily. Phoenix: ~6.5h. Berlin: ~3h. Nairobi: ~5.5h.
Step 3: Panel Efficiency Matters
AGAIC BSM715 HJT panels (23.5% efficiency) generate ~10% more per square meter than standard PERC. Hot climate? HJT's superior temperature coefficient (-0.26%/°C) adds 2–4% annual yield versus conventional panels.
Step 4: The Formula
System Size (kW) = Annual kWh ÷ (365 × Peak Sun Hours × 0.75)
For 10,500 kWh/year in Phoenix: 10,500 ÷ (365 × 6.5 × 0.75) = 5.9 kW. With 440W panels: ~14 panels.
Plan for Growth
Adding an EV or heat pump? Size for future consumption, not just today's. Try our free AgaicDesign tool →
