Size your system
Find it on your bill. US average is about 900 kWh/month.
Sets your peak sun hours (state average).
Editable — use your installer's PVWatts figure if you have one.
Sun hours, derate, and why installers oversize slightly.
Why your utility's policy changes the math.
The honest math, including the 2026 tax credit change.
Frequently asked
How many solar panels do I need for a 2,000 sq ft home?
Home size doesn't decide it — your kWh usage does. A home using 10,800 kWh/year needs roughly 6–8 kW (15–20 panels at 400W) depending on sun hours. Enter your actual bill above for your number.
What is a peak sun hour?
One hour of sunlight at 1,000 W/m² intensity. Arizona averages about 6.5 per day; Washington about 3.8. It bundles daylight length, angle, and cloud cover into one number installers actually use.
Can I install solar myself to save money?
DIY kits exist and cut labor cost, but permits, interconnection, roof work, and electrical code make professional install the norm for grid-tied homes. This calculator can't replace an electrician.
Is the federal solar tax credit still available in 2026?
No — for homeowner-owned systems. Section 25D ended for systems placed in service after December 31, 2025 (One Big Beautiful Bill Act, IRS FS-2025-05). Leased systems may still qualify for commercial credits through the leasing company.
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