How many solar panels do I need for a 2000 sq ft house?

A 2000 sq ft house typically uses 1,000-1,500 kWh/month. At 4.5 sun hours and 400W panels, you would need approximately 15-20 panels (6-8 kW system).

What is the formula for calculating solar panels?

Panels = (monthly kWh ÷ 30 ÷ sun hours ÷ panel kW) × 1.25 efficiency factor. The 1.25 accounts for real-world inefficiencies in inverter, wiring, and temperature.

How much electricity does a 400-watt solar panel produce?

A 400W panel in a 5-sun-hour region produces about 2 kWh per day, 60 kWh per month, or 720 kWh per year (accounting for 80% system efficiency).

What is the average cost of a solar system?

As of 2024, residential solar costs $2.50-$3.50 per watt installed. A typical 8 kW system costs $20,000-$28,000 before the 30% federal Investment Tax Credit (ITC).

What are peak sun hours?

Peak sun hours is the number of hours per day when solar irradiance equals 1,000 W/m². Arizona averages 5.5 peak sun hours; Seattle averages 3.0. More sun hours means more solar production.

Solar Panel Calculator — How Many Panels Needed

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Quick Answer

To estimate solar panels needed, divide your monthly kWh usage by 30 for daily kWh, then divide by daily sun hours and panel kilowatt rating, and multiply by 1.25 for efficiency losses. A 900 kWh/month home in a 4.5 sun-hour region needs about 18-20 panels at 400W each.

Use the Solar Panel Calculator below to get instant results.

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Solar Panel Calculator

Estimate how many solar panels you need based on your monthly electricity usage, location, and panel wattage.

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Cite This Tool

Solar Panel Calculator. (2026). Electrical Calculators Online. Retrieved from https://electricalcalcpro.com/solar-panel-calculator/

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