Solar Cost for a 1-Bedroom Apartment

What Size Solar System Does a 1-Bedroom Apartment Need?

Most 1-bedroom apartments need 2 kW to 4 kW to offset 45% to 90% of their electricity use. According to U.S. Energy Information Administration (EIA) 2020 Residential Energy Consumption Survey data, apartments in buildings with five or more units used about 139 billion kWh across 22.84 million households, which works out to roughly 6,100 kWh per year (about 507 kWh per month) per apartment (EIA Table CE4.1). That is a national average across all apartments, not a 1-bedroom-specific figure, so use your own bill.

To size a system, divide your annual kWh by the output per kW. At about 1,400 kWh per kW per year, 6,100 kWh calls for roughly 4.3 kW to offset everything. Output varies with location and orientation: sunny Southwest locations produce noticeably more per kW than cloudy Northwest locations, so run your address through NREL PVWatts before relying on any national figure. In practice, the limiting factor for an apartment is usually available roof or ground space and permission to use it, not electricity demand.

Under these assumptions a 2 kW system offsets about 46% of an average apartment’s annual electricity, a 3 kW system about 69%, and a 4 kW system about 92% (see the table above). If your usage is well below 6,100 kWh per year, a smaller system covers a larger share, so check your own 12-month total before choosing a size. Use our solar system size calculator to enter your actual kWh.

How Much Can Solar Save a 1-Bedroom Apartment, and How Long Is the Payback?

A 3 kW system saves roughly $760 per year, or about $63 per month, at the U.S. average residential electricity rate of about 18 cents per kWh. The EIA’s Electric Power Monthly put the 2026 national average near 18.3 cents per kWh in recent readings (EIA Electric Power Monthly), with state averages ranging from roughly 12.7 cents in Louisiana to about 34.7 cents in California. Simple payback (cost divided by annual savings, with no incentives and no rate increases) is therefore about 11.5 to 13.9 years at 18 cents per kWh using our $2.89 to $3.50 per watt range.

Your state’s rate changes that result dramatically, because payback is inversely proportional to the electricity price. The chart below uses a midpoint cost of $3.20 per watt and assumes every kWh your panels produce offsets a kWh you would have bought at the retail rate.

Chart summary: At about 12.7 cents per kWh (Louisiana) simple payback is roughly 18 years, at the U.S. average of about 18 cents it is about 12.7 years, and at about 29.5 cents (New York) it drops to about 7.8 years. California’s 6.6 years is a best case, because under the state’s Net Billing Tariff exported power earns far less than the retail rate. This chart assumes every kWh produced offsets retail-priced power.

Net metering rules decide how much of your output is worth the retail rate. In California, the Net Billing Tariff (often called NEM 3.0), effective April 15, 2023, credits exports at avoided-cost rates that analysts estimate average about 75% below the earlier near-retail credit, so self-consumption and batteries matter more there. Other states differ, so check your utility’s current policy with our net metering calculator and solar payback calculator.

Over 25 years, panel output typically declines about 0.5% per year according to National Renewable Energy Laboratory research, leaving a system at roughly 88% of its original output at year 25. Applying that decline to a 3 kW system at $9,600 (the $3.20 per watt midpoint) and a flat 18 cents per kWh gives about $17,800 of electricity value against $9,600 of cost: an estimated net gain near $8,200 before any rate increases, inverter replacement, or financing costs.

Chart summary: Starting from a $9,600 purchase (3 kW at $3.20 per watt), cumulative cash flow crosses zero between year 13 (about -$62) and year 14 (about +$647). By year 25 the system has returned roughly $17,808 in electricity value, a net gain of about $8,208. The line assumes flat electricity prices, so higher rate increases would shorten the break-even, while an inverter replacement or financing costs would lengthen it.