Independent research · Calculators · Rules by location

Plug-in solar and home backup power, worked out.

Find out if a plug-in solar kit is allowed where you live, what it could save you, and which power station keeps your essentials running in an outage.

Check the rules where I live Run the savings calculator
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  • Methods published
  • Re-checked when rules change

Quick estimate

Works in any currency
800 W

UK kits are capped at 800 W. US limits vary by state.

4.0 h
0.20 / kWh

Output a year

993 kWh

Saved a year

159

Assumes 85% system efficiency and that you use 80% of what the kit makes.Open the full calculator

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Do the maths before you buy

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Savings calculator

See what a plug-in kit could take off your bill, and how fast it pays for itself.

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State rules map

Check the plug-in solar rules for your US state or the UK.

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Runtime calculator

Find out how long a power station runs your fridge, router or CPAP.

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Battery size calculator

Work out how many kWh you need to get through an outage.

Rules by location

Is plug-in solar allowed where you live?

The UK legalised plug-in solar kits on 27 August 2026. In the US, each state sets its own rules. Utah, Virginia, Colorado, Maine and Maryland were among the first to pass laws.

Open the rules map

United Kingdom

Allowed
  • Up to 800 W (AC)
  • One kit per property
  • Tell your DNO within 28 days

United States

State by state
  • Laws passed in a growing list of states
  • Bills debated in more
  • Check your utility's rules too

Latest guides

All guides
Plug-in solar · UK

Plug-in solar in the UK: the rules, the 800 W limit and your DNO

What changed on 27 August 2026, what you can plug in, and the one form you need to send.

Read the guidePlug-in solar · US

Best plug-in solar kits for apartments

Balcony-friendly kits compared on output, certification and what your state allows.

Read the guidePower stations

EcoFlow vs Jackery: which power station should you buy?

Capacity, output, charging and expansion, side by side.

Read the comparisonHome backup

Home battery backup without solar: what works

Charging from the grid, sizing for an outage and what it costs.

Read the guidePower stations

How long will a power station run a fridge?

A simple way to read Wh and W, with a calculator for your own appliances.

Read the guideHome backup

Solar battery storage: what it really costs

Price per kWh, installation and the running costs nobody lists.

Read the guide

How we work

Numbers you can check, not just opinions.

PlugWattLab is funded by display ads. Brands can't pay to be ranked, and every figure on the site links to how we got it.

Read our methods

01

Source

We start from the law, the spec sheet and published independent tests, and link to each one.

02

Compare

Specs go into one database, so every product is judged on the same fields.

03

Explain

Calculators show their assumptions. Change any input and see what moves.