How Much Would 12 Solar Panels Cost?

As a useful UK benchmark, Energy Saving Trust says a 4.5kWp system typically covers around 20–30m² and uses about 12 panels.

That does not mean every set of 12 panels will fit within exactly the same area. Panel sizes vary between manufacturers and models.

You also cannot treat every square metre of roof as usable. A chimney, roof window or shaded section may make part of the surface unsuitable.

Before ordering equipment, have the installer check the available roof area and show you where the panels will go.

Is 12 Panels Enough For Your Electricity Use?

This is where your household's electricity consumption becomes more useful than the panel count.

A small household with modest electricity use may get a substantial amount of its annual electricity from 12 panels. A larger household with high consumption may need a larger system if the roof allows it.

Your electricity bills can help establish the starting point. Look at how many kilowatt-hours you use over a year rather than focusing only on the amount you pay. Your bill may also show whether your usage is relatively consistent or changes significantly between seasons.

Someone who works from home, for example, may use more electricity during daylight hours than someone who leaves the property empty most of the day. That difference can affect how much of the solar electricity gets used directly in the home.

Energy Saving Trust's solar calculator can estimate a suitable system size, installation cost and potential savings using information about your property and energy use.

What If Your Roof Can Fit More Than 12 Panels?

You do not necessarily need to stop at 12.