How many solar panels do you need for 2,500 kWh a month?

About 51 panels (21.4 kW) in the median American city, covering roughly 1,201 square feet of roof. At today’s prices that system costs $54k to $80k before incentives. Where you live changes the count by up to 60%.

A new two-storey American house with a garage and a young tree — 51 panels of 420 W make about 30,000 kWh a year in a typical U.S. city.

Panels (420 W)51median U.S. city

System size21.4kW

Roof space1,201ft²including gaps

Price range$54k–$80kbefore incentives

Panels needed for 2,500 kWh a month, by city

City	kWh per kW	System	Panels
Seattle, WA	1,125	26.7 kW	64
Portland, OR	1,170	25.6 kW	62
San Francisco, CA	1,527	19.6 kW	47
Los Angeles, CA	1,707	17.6 kW	42
Phoenix, AZ	1,781	16.8 kW	41
Las Vegas, NV	1,804	16.6 kW	40
Denver, CO	1,605	18.7 kW	45
Salt Lake City, UT	1,556	19.3 kW	46
Dallas, TX	1,467	20.4 kW	49
Houston, TX	1,401	21.4 kW	51
Minneapolis, MN	1,311	22.9 kW	55
Chicago, IL	1,253	23.9 kW	58
Detroit, MI	1,236	24.3 kW	58
Atlanta, GA	1,367	21.9 kW	53
Miami, FL	1,499	20.0 kW	48
Charlotte, NC	1,405	21.4 kW	51
Washington, DC	1,318	22.8 kW	55
New York, NY	1,296	23.1 kW	56
Boston, MA	1,274	23.5 kW	57

South-facing 25° roof, standard losses, 100% of yearly use. East or west roofs need about 10–20% more.

Month by month in Lincoln, NE

A typical-sunshine city: 51 panels over-produce from spring to autumn and fall short in winter. Net metering lets the summer surplus pay for the winter shortfall; net billing does not.