It depends on three numbers: what you pay for electricity, how much sun your panels get, and what the kit costs. Here they are for each state with a plug-in law.
The short answer
For an 800 W kit costing $1,099, with panels tilted toward the sun and a typical share of the power used at home (69%), payback ranges from about 3.8 years in California to about 10.1 years in Utah. If you used every kilowatt-hour yourself (the best case), it would be 2.6 and 6.9 years. The gap between states is mostly the price of electricity: California averages 32.34¢ per kWh, Utah 13.26¢.
Panels hung flat on a balcony railing produce about 61–77% of what tilted panels make in these states, so at the typical share payback stretches to about 6.2 years in California and 15.1 years in Utah. Railing vs tilted panels, state by state.
Our example
We use a real product from our kit list: the EcoFlow STREAM Microinverter + 2 x 400W Rigid Solar Panels, 800 W of panels, listed at $1,099 on November 10, 2026. We assume you earn nothing for power sent to the grid: most of these laws exclude plug-in systems from net metering, and the rest do not promise any payment. So what matters is how much of the output you use at home:
Typical (69%): from HTW Berlin's plug-in solar model for an 800 W system without a battery, in a home using 3,000 kWh a year. That is well below every US state's average household use, so most homes will use at least this share.
Best case (100%): you use every kilowatt-hour yourself, for example because something always runs in the daytime.
Panels are assumed tilted at 20° facing south, as on a sunny patio, with a second case for panels hung vertically on a south-facing railing.
Yearly savings and payback for a 800 W kit costing $1,099
Your electricity price. This matters most. Check your bill's price per kWh, including delivery charges, and use it in the calculator.
Using the power yourself. Savings come from power you use while the sun shines: the fridge, a router, things on standby. Power sent back to the grid usually earns nothing. Vermont's law says so directly. Connecticut's law requires devices to warn that exports may be charged to you as usage, unless your meter supports net metering.
Direction and shade. East- or west-facing balconies and shade from buildings cut output. The figures above assume south-facing panels with no shade.
The kit's real price. Prices change often. Kits that bundle a battery cost more and pay back more slowly unless you can shift power into the evening.
Size limits. Most state laws cap output at 1,200 W, and Colorado at 1,920 W. A kit over the cap is not covered by the law.
Is it legal where you live?
Savings mean little if the system isn't allowed. California (from January 1, 2027), New Jersey (from March 1, 2027), Virginia (from January 1, 2027) have laws that are not in effect yet, and New Hampshire reportedly signed one that we are still verifying. Several states require a specific safety certification, and no complete kit has shown us that certificate yet. See Certification watch.
Prices: U.S. EIA, Form EIA-861M: Sales and revenue data by state, monthly (sales_revenue.xlsx), residential average for September 2025 – August 2026 (12 months).
Solar output: NREL (National Laboratory of the Rockies) PVWatts v8, typical meteorological year weather, run for each state capital with 14% system losses (PVWatts documentation).
Share used at home: HTW Berlin, Stecker-Solar-Simulator: 800 W, no battery, vertical, facing south, German weather and household patterns. It gave 56% at 2,100 kWh/yr, 69% at 3,000 kWh/yr, 88% at 5,000 kWh/yr (simulator, method). Average US household use is 10,499 kWh/yr (EIA Form 861M).
No incentives, no payment for exports, no change in electricity prices, and no inverter clipping.
Numbers update automatically when we refresh prices or solar data. Last price update: November 10, 2026.
This page is general information, not legal or electrical advice. Laws change and utilities differ. Check the linked official sources, your lease or HOA rules, and your utility before you buy or install anything. Full disclaimer.