Plug-in solar is not yet legal to sell, supply or use in the UK. A Government consultation is open until 30 June 2026. Read the UK legal status

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Savings & payback

What can a 400W solar panel power?

A single 400W panel is a popular starting point for plug-in solar, so it's natural to ask what it can run. As with any small system, it's best understood as offsetting your background daytime use rather than 'powering' specific appliances.This guide gives a realistic picture. For yearly energy figures, see 400W output.

Written and edited by Christopher Panteli

Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.

Putting 400W in context

400W is roughly enough, at peak, to cover the constant background draw of a typical home — fridge, router, lighting and standby devices. Outside the brightest hours, output is lower. So a 400W panel is a steady contributor to your daytime base load, not a way to run big appliances.

Common loads versus 400W of solar.
LoadRough powerWithin 400W?
Router, lighting, laptop~100–250WYes
Fridge-freezer (cycling)~100–200W averageYes
Microwave / washing machine~800–2,000WNo (high draw)
Kettle / oven~2,000–3,000WNo

Timing matters most

Because a panel can't store energy without a battery, the saving comes from using its output during daylight. Running flexible loads at midday uses solar directly; the same task at night means buying from the grid. This is solar self-consumption in action.

Keep expectations realistic

A 400W panel supplements your supply; it doesn't power a home. Treat figures as estimates, and note plug-in solar is not yet legal to use in the UK (legal status).

Frequently asked questions

Can a 400W solar panel run a fridge?
In good daylight, 400W can cover a fridge-freezer's average cycling draw, which is typically 100–200W. It won't reliably cover the brief high-power moments of bigger appliances on its own.

Sources

  1. 1. PVGIS (Photovoltaic Geographical Information System) European Commission, Joint Research Centre

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