How Many Solar Panels for a 2,000 sq ft Roof?
A 2,000 sq ft roof with good southern exposure fits roughly 25โ30 panels (400W each) โ a 10โ12 kW system producing 13,000โ16,000 kWh per year in average US sun. This guide sizes the system, derates for shade and orientation, and frames the payback against your utility rate.
Step-by-Step Takeoff
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Usable roof: ~60% of 2,000 sq ft after setbacks and shading = 1,200 sq ft.
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Panels: 1,200 รท 18 sq ft per 400W panel โ 60 max; typical installs use 25โ30 for a 10โ12 kW system.
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Output: 10 kW ร 1,400 sun-hours โ 14,000 kWh/year.
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Shade audit: chimneys, vents, and winter trees cut more than panel specs suggest โ model shade in the calculator.
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Inverter choice: string inverters are cheapest; microinverters win on partially shaded roofs.
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Payback: system cost after credits รท yearly bill savings, usually 6โ10 years.
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Model your roof, shading, and rates in the Solar Calculator.
Guide FAQ
How many panels to offset $200/month?
Roughly 20โ28 ร 400W panels depending on rates and sun-hours โ model it with your utility rate.
Do panels work on east-west roofs?
Yes at ~80โ85% of south-facing output; split arrays across both slopes.
How long do solar panels last?
25โ30 year warranties at ~80% output; inverters typically need one replacement in that span.
Do I need batteries?
Only for backup or time-of-use arbitrage โ grid-tied net metering pays back faster without them.
What roof condition is required?
At least 10โ15 years of shingle life left; re-roof first if the roof is tired.
Related Guides
How Many Shingles for a 2,000 sq ft Roof?
Roofing squares, bundles, underlayment, ridge caps, and waste for a 2,000 sq ft gable roof.
How Much Insulation for an Attic?
R-value targets by zone, batt counts, blown-in bags, and air-sealing order for a 1,000 sq ft attic.
Is My 200A Panel Overloaded? Do the Math
Existing 80A load plus new circuits against a 200A service, demand factors, and upgrade triggers.