How many solar panels do I need for my home? 2025 guide
According to the U.S. Energy Information Administration (EIA), the average American household uses 10,791 kWh of electricity per year (or about 900 kWh per month), so
A panel will usually produce between 250 and 400 watts of power. For the equation later on, assume an average of 320 W per panel. Use your annual energy consumption and solar panel rating to calculate the production ratio. You can calculate the production ratio when you have the numbers for your annual energy usage and the solar panel wattage.
Look at different panels and see what the wattages are. The solar panel wattage is also known as the power rating, and it's a panel's electrical output under ideal conditions. This is measured in watts (W). A panel will usually produce between 250 and 400 watts of power. For the equation later on, assume an average of 320 W per panel.
A 400-watt panel can generate roughly 1.6–2.5 kWh of energy per day, depending on local sunlight. To cover the average U.S. household's 900 kWh/month consumption, you typically need 12–18 panels. Output depends on sun hours, roof direction, panel technology, shading, temperature and age.
The goal for any solar project should be 100% electricity offset and maximum savings — not necessarily to cram as many panels on a roof as possible. So, the number of panels you need to power a house varies based on three main factors: In this article, we'll show you how to manually calculate how many panels you'll need to power your home.
PDF version includes complete article with source references.
Get technical specifications, application guides, and ROI analysis tools for containerized power stations, portable photovoltaic containers, and microgrid energy storage solutions.
18 Industrial Park Road, Midrand
Johannesburg, South Africa 1685
Sales & General: +27 11 568 3400
Technical Support: +27 82 459 7781
Monday - Friday: 8:00 AM - 6:00 PM SAST
Saturday: 8:00 AM - 2:00 PM SAST