Is plug-in solar worth it?

Payback numbers, by state and kit

The payback table shows results for three kit types across all states. For the small kit (up to 400 W of panels, no battery, price $799) the shortest computed payback is 6.3 years in Hawaii and 6.7 years in California; the longest is 23.7 years in Washington, and no states are over 25 years for that kit (the calculator supplied these numbers).

For the mid-size kit (800–1,200 W of panels, no battery, price $2,250) the calculator gives a shortest payback of 10.6 years in Hawaii; the computed table also reports 36 states with payback over 25 years. For the kit with a battery (2000 W of panels, 3,000 Wh battery, price $8,199) the shortest payback is 16.5 years in Hawaii and the table shows 44 states with payback over 25 years.

Those payback figures assume 2.5% annual inflation and no maintenance cost, and they treat the kit as a cash purchase. When payback is under 10 years, the U.S. Department of Energy says solar is usually more attractive than other low-risk investments.

What moves payback the most

Electricity price is the single biggest lever. The calculator shows an 800 W kit in California (33.25 cents/kWh) produces 811 kWh a year vertical and saves $157 a year, while the same kit in Texas (16.06 cents/kWh) produces a similar amount of energy but is worth only $68 a year — roughly half the annual savings (results from the calculator).

Panel direction and tilt matter next. In the California example the same 800 W kit tilted at 30° facing south rises from 811 kWh to 1,354 kWh a year and increases the annual savings (the calculator gives $189 for the 30° tilt vs $157 vertical). The azimuth table for New York and Los Angeles shows production varying hundreds of kWh by orientation and tilt.

Your home’s base load changes how much of the kit’s output you use rather than export. In Los Angeles at 33.25 cents/kWh an 800 W kit with a 100 W base load uses 315 kWh at home; with a 300 W base load it uses 679 kWh at home — that increases the kit’s value because onsite use displaces retail electricity.

Adding a battery raises self-consumption and thus the kit’s dollar value, but batteries raise the upfront price a lot. The calculator shows in Los Angeles (33.25 cents/kWh) an 800 W kit with a 0 kWh battery yields $105–$226 a year depending on base load, while adding 1–4 kWh batteries can push used-at-home energy from about 38% to nearly 100% in some scenarios — the tradeoff is the battery cost included in the battery kit price.

When it’s often not worth it

If your computed payback is long — well over 10 years — many homeowners find other low-risk investments more attractive. The mid and battery kits show dozens of states with payback over 25 years, which the calculator flags as a poor financial match for a cash purchase.

Shade or poor orientation reduces production sharply: a panel in partial shade produces far less than one in direct sun, and rooftop obstructions can make rooftop systems unsuitable. If your utility pays little or nothing for exported energy the kit’s value falls further (the California example assumes exports paid 0).

Kits with batteries are the most expensive up front ($8,199 median price for the battery kit) and in the computed table the battery kit rarely pays back within a homeowner’s typical investment horizon; they are usually a poor financial choice if your only goal is bill savings.

Value beyond simple payback

Payback years capture only bill savings. Plug-in systems can be useful where rooftop or ground-mount panels aren’t possible — for example, trees that create excessive shade can make rooftop panels not an option. For renters and people without roof access a small plug-in kit can be the only on-site solar option.

Timing and matching to loads matter: plug-in solar produces most in hot, sunny afternoons, which is when air conditioning and many time-of-use rates peak. That alignment raises practical value beyond a simple dollars-per-kWh calculation.

Outage backup is only available with the right hardware and a battery-equipped kit; the site’s kit cards show which models include usable storage. Check whether your purchase might qualify for the federal residential solar energy credit if you buy or finance a system.