The number of solar panels needed to power a house varies based on factors such as electricity consumption, geographic location, roof size, and panel specifications. However, here are some general estimates and guidelines:
- An average home typically requires between 15 and 22 solar panels to fully offset its electricity bills, depending on energy usage and sunlight availability
- For homes by size:
- About 7 panels for a 1,000 sq. ft. home (around 4,700 kWh/year)
- Around 14 panels for a 2,000 sq. ft. home (around 9,400 kWh/year)
- Approximately 18 to 21 panels for homes between 2,500 and 3,000 sq. ft.
- In the UK, a 1-2 bedroom house may need 4 to 8 panels (2-3 kW system), while a 4-5 bedroom house might require 13 to 16 panels to cover typical electricity needs
- The wattage of panels also matters; common panels range from 320W to 450W. For example, a system sized around 7.2 kW (using 450W panels) might need about 16 panels in a sunny location like California
- Specific appliances or add-ons like electric vehicles or pools can significantly increase energy needs and thus the number of panels required
- A rough formula to estimate the number of panels is:
Number of panels=Annual electricity usage (kWh)Production ratio×Panel wattage (kW)\text{Number of panels}=\frac{\text{Annual electricity usage (kWh)}}{\text{Production ratio}\times \text{Panel wattage (kW)}}Number of panels=Production ratio×Panel wattage (kW)Annual electricity usage (kWh)
where the production ratio accounts for local sunlight hours and panel efficiency
In summary, most average homes need between 15 and 22 solar panels to cover their electricity needs fully, but smaller homes or those with lower energy use may need fewer panels, while larger or high-usage homes may require more
