How Much Does Plug-In Solar Actually Save? The 2026 Arithmetic

Let us do this properly, with real numbers, and without the phrase "free energy."

A plug-in solar kit is a capital purchase that reduces a recurring cost. That makes it the same kind of decision as a heat pump water heater or better attic insulation: worth doing when the arithmetic works, not worth doing when it does not.

Here is the arithmetic.

Step one: how much will it generate?

Output depends on four things — panel wattage, sun hours where you live, orientation and tilt, and shading.

As a working range, an 800-watt kit produces roughly 650 to 1,400 kWh per year in the United States. The high end is a south-facing, unshaded, properly tilted array in Arizona or Southern California. The low end is a vertical, east-facing balcony rail in Seattle.

Manufacturer figures sit near the top of that band. Hoymiles rates a single 360 W HiFlow Pro unit at 721 kWh annually, and 2,403 kWh with four units in parallel at the 1,200 W cap. Treat those as best-case laboratory-adjacent numbers and discount 20–30% for a real balcony.

A reasonable planning figure for a typical US installation of an 800 W kit is 900–1,100 kWh a year.

Step two: what is a kWh worth to you?

This is where the answer diverges wildly by state. The US residential average was 18.44¢/kWh on the EIA's May 2026 data — the figure most rate trackers were still citing in August 2026. But Idaho pays 12.35¢ and Hawaii pays about 52¢ — a four-fold spread that swamps every other variable in this calculation.

Find your actual rate on your bill, and use the all-in figure: total dollars divided by total kWh, including delivery charges, not just the supply rate. Delivery is often half the bill, and solar offsets it too.

Step three: the variable nobody mentions

Here is the one that separates a good outcome from a disappointing one.

Plug-in solar has no battery and, in nearly every state, no net metering. Utah's law excludes portable devices from net metering outright; New York's SUNNY Act exempts them from it. Electricity you generate but do not use at that moment is exported to the grid for nothing.

So your real saving is not annual production times your rate. It is:

annual production × self-consumption rate × your all-in rate

Self-consumption rates observed in practice run from about 20–40% for a household that is empty all day to 80–95% for one where someone works from home. That is a 3–4× difference in return from the identical hardware.

Run it: an 800 W kit generating 1,000 kWh at 25¢/kWh.

• Away all day, 30% self-consumption → 300 kWh used → $75/year
• Home during the day, 85% self-consumption → 850 kWh used → $213/year

Same panels. Same sun. Nearly three times the money.

This is why the standing advice is to size to your daytime baseload. Add up what runs continuously — refrigerator, freezer, router, ONT, standby loads, a home office setup — and that is the wattage worth covering. For most apartments that is 150–400 watts, which is a striking argument for the small, cheap kits over the maximum-legal ones.

Step four: what does it cost?

Real 2026 US pricing spans a wide range:

An 800 W setup at around $1,099 is the figure New York legislators worked with, alongside an estimate of roughly $300 a year in bill reduction for an average New York household — a state where power is expensive. California's SB 868 sponsors used a smaller example: a 400 W system covering about 14% of average apartment usage and saving roughly $250 a year.

Step five: payback

Divide cost by annual saving.

• $1,099 kit, $300/yr saving (New York) → 3.7 years
• $700 kit, $250/yr saving (Los Angeles at 28¢) → 2.8 years
• $1,100 kit, $180/yr saving (US average, decent self-consumption) → 6.1 years
• $1,100 kit, $85/yr saving (cheap-power state, away all day) → 13 years

Published ranges cluster at three to six years for high-rate markets, with 25-year lifetime savings quoted between $3,500 and $9,000. Those long-horizon figures assume the panels last, the microinverter does not fail, and rates keep rising — the first two are reasonable, the third is likely but not guaranteed.

Three things that change the answer

The federal tax credit is gone. The 30% residential clean energy credit expired December 31, 2025. Some state credits survive — New York offers 25% up to $5,000, Massachusetts 15% up to $1,000 — so check yours, but most buyers now pay list price.

Batteries improve self-consumption and worsen payback. Adding roughly 1 kWh of storage for $800–$1,500 can push self-consumption above 90%. It also roughly doubles the cost. It usually makes sense only where rates are very high or time-of-use spreads are steep.

Rate structure matters. On a time-of-use plan where the peak window is 4–9 p.m., midday solar offsets your cheapest hours, which quietly cuts the value of every kWh you generate. On a flat rate, every kWh is worth the same.

The honest bottom line

At the US average rate, in a household with someone home during the day, a $900 kit generating 1,000 kWh at 80% self-consumption saves about $147 a year and pays for itself in roughly six years. After that it is genuinely money in your pocket for another fifteen or twenty.

That is a decent, unglamorous return — comparable to a good home efficiency upgrade. It is not free electricity, and anyone selling it to you that way is telling you something the arithmetic does not support.

Sources

1. ChooseEnergy — Electricity rates by state August 2026
2. Solar.com — Guide to balcony and plug-in solar
3. WattBuild — Balcony solar in the US in 2026
4. Canary Media — New York balcony solar bill
5. EWG — California balcony solar bill
6. Electrek — First UL 3700 balcony solar microinverter

Tools

• Check the law in your state
• Savings and payback calculator
• Which kit to buy

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