Is plug-in solar worth it? Real savings and payback in 2026

The sum

Every estimate on this page uses the same three steps, the ones behind our savings calculator:

1. Yearly output = kit output (W) × peak sun hours × 365 × 0.85, divided by 1,000 for kWh. The 0.85 covers heat, dirt, wiring and inverter losses.
2. Yearly saving = yearly output × the share you use at home × your price per kWh.
3. Payback = kit price ÷ yearly saving.

The share you use at home is the number most people overlook. Power you don’t use when it’s made goes back to the grid, usually unpaid, so a kit that makes lots of electricity while everyone’s out at work saves much less than its output suggests.

The UK numbers

We used the Ofgem price cap unit rate for October to December 2026, 26.32p per kWh, and an 800 W kit costing about £600, in line with what Argos charged for UKSOL’s cheapest kit. Sun hours of 2.5 a day are typical for much of England.

Situation	Yearly output	Used at home	Saving a year	Payback on £600
Good: south-facing, tilted, someone home in the day	about 620 kWh	80%	about £130	about 4.6 years
Typical: panels hanging on a balcony railing	about 465 kWh	70%	about £86	about 7 years
Poor: east-facing, some shade, out all day	about 300 kWh	60%	about £47	about 12.7 years

A smaller kit can make more sense than it looks. Octopus Energy sold a single 460 W panel bundle for £450 in autumn 2026. In a good spot it makes about 360 kWh a year, and because it rarely produces more than a home’s background load, you might use 90% of it. That’s about £85 a year, a payback of a little over five years.

For comparison, pv magazine reported savings of up to £110 a year when the rules changed in August, which sits inside our range.

The US numbers

The EIA expects US households to pay about 18.2 cents per kWh on average in 2026, but prices vary enormously by state, from around 11 cents to well over 30. Complete kits from established brands cost roughly $870 to $1,280 in mid-2026.

Situation	Kit	Yearly output	Used at home	Price per kWh	Saving a year	Payback
Average-price state, balcony railing	1,200 W, $1,100	about 1,260 kWh	60%	18.2 cents	about $137	about 8 years
High-price state, sunny balcony	800 W, $900	about 930 kWh	70%	32 cents	about $208	about 4.3 years
Cheap power, some shade	800 W, $900	about 745 kWh	60%	13 cents	about $58	about 15 years

The US examples assume 4 to 5 peak sun hours and a quarter of the output lost to a near-vertical railing mount. In a high-price state such as California, plug-in solar can pay back quickly. Where power is cheap, it’s a long wait.

Remember that you can only use a kit legally in states that allow it, and five of the ten states with laws don’t start until 2027. Check our US rules guide first.

What moves the numbers

Using more of what you make is the cheapest improvement. Run the washing machine, dishwasher or air conditioning in the middle of the day. Set the dishwasher on a timer for noon before you go out.

Angle and direction. A panel tilted toward the south makes noticeably more than one hanging flat against a railing. East or west costs some output, north costs a lot. Check your spot with PVGIS or PVWatts.

Shade. Even partial shade on one panel can cut a kit’s output sharply.

Electricity prices. If prices rise, the kit pays back faster. If they fall, it takes longer.

Kit size. Match it to your daytime use. A big kit in a small, empty apartment exports most of what it makes.

When it isn’t worth it

• Your balcony or garden faces north, or is shaded for most of the day.
• Your electricity is cheap and nobody’s home in the day.
• You’ll move soon to somewhere without a suitable spot.
• Your state doesn’t allow plug-in solar yet.

In those cases, your money goes further elsewhere, such as LED lighting, a more efficient fridge, or a time-of-use tariff.

Beyond the money

Some people buy a kit for reasons that don’t show up on a spreadsheet: using more of their own clean power, watching the output in an app, or teaching children where electricity comes from. Those are fine reasons, as long as you go in knowing the financial payback is measured in years, not months.

Before you buy, read how plug-in solar works, and if you’re in the UK, the UK rules, including the registration you need to do before switching on.