Solar Panel
Calculator

How much energy does a solar panel produce?

A 400 W panel in an average location (4 peak sun hours/day) produces about 0.4 kW × 4 h × 365 days ≈ 480 kWh per year, before system losses. A typical 5 kWp system makes 4,000–7,000 kWh/year depending on your region.

What is the average solar payback period?

With today's prices and incentives, most home systems pay back in 5–10 years and keep producing for 25+ years. Use the calculator with your region and electricity price for a precise figure.

How much can I save with solar panels?

For a 5 kWp system at $0.15/kWh, you generate roughly $600–1,000 of electricity per year, rising with electricity price inflation. Over 25 years that can reach $20,000–30,000.

Do solar panels work in cloudy or cold countries?

Yes. Panels produce from diffuse light too — Germany, with modest sun, is one of the world's biggest solar markets. Cold weather even improves panel efficiency slightly.

What is the ROI of a solar installation?

After payback, the system generates pure savings for its remaining life. Typical 25-year ROI is 100–300%, depending on incentives, electricity prices and your location.

How long do solar panels last?

Panels are typically warrantied for 25–30 years and degrade about 0.4–0.5% per year, so they still produce ~85% of their original output after 25 years.

How many panels do I need for my house?

A typical home uses 4,000–6,000 kWh/year. At 480 kWh per 400 W panel per year, that is 9–13 panels (a 3.6–5.2 kWp system).

What are peak sun hours?

The number of hours per day when solar irradiance equals 1,000 W/m². It is the standard way to estimate daily production: 5 kWp × 4 h × 0.8 efficiency ≈ 16 kWh/day.