10kW solar panel systems: the expert guide

When you’re thinking of getting a solar panel system, you want to ensure it matches your home’s requirements.

A 10kW solar panel system is a great choice if you have a high-consumption household – or if you can afford to maximise your investment by using more roof space.

In this guide, we’ll explain what a 10kW solar panel system is, how many household items it can generally run, and why getting a larger system could be a good idea regardless of your usage.

If you’re wondering how much you could save with a solar & battery system, enter a few details below and we’ll generate a quick estimate.

What is a 10kW solar panel system?

A 10kW solar panel system has a peak power rating of 10 kilowatts, which means it’d generate 10,000 kilowatt-hours (kWh) of electricity per year in standard test conditions.

These conditions include a cell temperature of 25°C and solar irradiance of 1,000W per square metre (m²), and is how every manufacturer checks its solar panels’ abilities.

Your system won’t necessarily produce 10,000kWh though, since solar panel output depends on aspects of the installation including the location, roof angle and direction, and quality of the hardware involved.

You can put together a 10kW system out of solar panels with output ratings that add up to 10,000 watts (W) – for example, 25 panels that all have a 400W rating.

As you might gather from that example, 10kW is a particularly large size for a solar panel system. The average domestic solar installation in the UK in February 2025 was 4.6 kilowatt-peak (kWp), according to the Microgeneration Certification Scheme (MCS).

However, there are plenty of households that require a big system – and if you have the space on your roof, it may be worth filling it even if your usage isn’t that high. We’ll go into more detail about that later.

You might also see a 10kW solar panel system referred to as a 10kWp (kilowatt peak) system. In this context, there’s no difference between the two.

How many solar panels are in a 10kW system?

The number of solar panels in a 10kW system depends on the power rating of the panels themselves.

If you’re using 400W panels, they’ll each generate 400 watt-hours in standard test conditions.

If you get 25 of these 400W panels installed on your roof, you’ll have a 10kW system, which produces 10,000kWh per year in these conditions.

The higher your panels’ power ratings, the more electricity your panels will generate, everything else being equal – and the more money you'll save and earn.

The table below runs through how many panels you’d need in order to create a system that’s at least 10kW, depending on the panels’ power ratings.

What size battery should you add to a 10kW system?

You should generally add at least a 10kWh battery to a 10kW solar panel system.

This will mean you can store your excess solar electricity all year round, to use on overcast days and after the sun sets.

You’ll be able to use more of the abundant electricity your solar panels generate in spring and summer, and squeeze every drop out of their output in autumn and winter, to reduce your dependence on the grid as much as possible.

The ideal size of your battery will depend on multiple factors though, such as the solar export tariff you’re using, your home’s electricity consumption levels, and whether you use more electricity in summer or winter.

For example, if you have an air conditioning system, you might use more solar electricity in summer than most homes, so you may not need as much battery storage.

On the other hand, if you have a heat pump, you’ll likely require even more electricity in winter than most households, meaning a larger battery could make sense – as long as you’re on an import tariff with a cheap off-peak rate.

These tariffs, which include British Gas Electric Driver and E.ON Next Drive, have low overnight rates which enable households to charge their storage batteries cheaply, then use that electricity over the rest of the day.

This will allow you to sell most of the electricity your solar panels generate to the grid, depending on how large your battery is, which can significantly increase your earnings – and you don’t need an electric car to qualify for one of these tariffs.

Your battery’s size will also depend on how long you spend at home during the day. For instance, if members of your household spend most days in an office or school, you may need a bigger battery, since you won’t be using most of the solar electricity as it’s produced.

To learn more, check out our guide to solar battery sizing.

What size inverter should you add to a 10kW system?

You should add a roughly 7kW inverter to a 10kW system, since the total power rating of your solar panels should be around 50% bigger than your inverter, as a rule.

This is because solar panels in the UK don’t usually reach their peak power rating, as our weather generally falls short of standard test conditions.

A 10kW system can still save (and earn) you hundreds of pounds with the electricity it generates, but unless it’s in one of the sunniest places in the UK, it won’t produce much more than 10,000kWh per year.

And it’s more efficient to choose an inverter that matches your system’s genuine output, instead of its production level in an ideal scenario. 

All inverters require a minimum amount of power to function, known as the 'startup voltage'. If your inverter's too big, it may struggle to reach this startup voltage.

This is useful information to know if you're considering the switch to solar, but choose a good installer and you can rely on them to size your system's inverter properly.

How much energy will a 10kW solar panel system generate?

What can a 10kW solar panel system run?

A 10kW solar panel system should be able to run the average four-bedroom household on a standard day, plus a heat pump and electric vehicle.

The system can generate around 23.3kWh of solar electricity per day in the UK, on average.

With this electricity, you can power all of the products below for the stated amount of time, according to data from the Centre for Sustainable Energy and our own calculations – and still have some left over.

It’s always worth getting a solar panel system that produces more electricity than your household consumes.

You can use most of this solar-generated electricity to significantly lower your bills by reducing the amount you need to import from the grid.

You won't use it all, as your system’s output will sometimes exceed how much you can consume, even with a battery. This is particularly common on sunny summer days.

This is where export tariffs come in. You can send all of this excess electricity to the grid – and if you use one of the best export tariffs, you can earn hundreds of pounds per year.

If you want to find out more about sizing your system, read our guide to working out how many solar panels you need.

However, you should always get a larger solar panel system if you can afford to. Most of the cost of a solar installation is tied up in scaffolding and labour, so adding more panels won’t push up your total by much.

And considering how much money an extra solar panel can save you over its lifespan, you should always maximise your roof space if possible.

This is the case even if your home’s consumption level is average, since exporting excess electricity can earn you loads of money.

How much space do you need for a 10kW solar panel system?

You’ll need 70.56m² of roof space for a 10kW solar panel system, roughly.

This figure takes into consideration the average height and width of a solar panel, which is around 2m² overall, plus the extra spaces installers usually factor in.

Your installation team will generally leave a 40cm gap between the panels and the sides of your roof, and 3cm between each panel, to follow MCS guidelines.

If your roof has a chimney, vent pipe, or skylight (also known as a Velux window), you’ll require a little more space – but not much.

If you have all three, you’ll need roughly another 0.81 m², for a total of 71.37m².

For more information on how solar panels will fit in, check out our guide to whether your roof is suitable for solar panels.

Do you need planning permission for a 10kW solar panel system?

You don’t generally need planning permission to install domestic rooftop solar panels, including 10kW systems.

Solar installations on households almost always fall under permitted development rights, which enable homeowners to carry out medium-sized measures without applying for planning permission.

In most cases, you’ll only need planning permission if you live in a flat, listed building, or conservation area – or if you’re looking to get ground-mounted solar panels.

However, your installer will have to send a G99 application to your region’s Distribution Network Operator (DNO) if your inverter’s maximum capacity is over 3.68kW on a single-phase system.

Considering your solar panel system will usually be around 50% larger than your inverter – meaning a 10kW system should come with a roughly 7kW inverter – a G99 application should be a necessity.

Most G99 applications are thankfully accepted without any problems, with the DNO viewing it as a way to find out about your system, and use that information to run its grid efficiently.

Can you get an off-grid 10kW solar panel system?

You can certainly get an off-grid 10kW solar panel system.

Since you won’t be able to export excess electricity to the grid, you’ll need a large battery to store as much energy as possible, so you can power your home on cloudy days and at night.

Depending on your location and electricity usage, a 13kWh battery may suit your needs.

The lower your usage, the more likely you are to run all of your electrical items with a 10kW system – though if your consumption is close to the national average of 3,400kWh, you may want to consider a smaller installation.

A 10kW system can be extremely profitable for households that are connected to the grid, as they can sell excess electricity through an export tariff – but for an off-grid home, it’s a large expense that may result in a lot of wasted energy.

Is a 10kW solar panel system worth it?

A 10kW solar panel system is definitely worth it in the long term, even if your household electricity consumption is relatively low.

On average, you can save 86% on your electricity bills with a solar & battery system.

This figure is based on a sample of over 150 systems installed by Sunsave across England and Wales in 2024 – though the average system in this sample is 6.1kW, so your savings may well be higher with a 10kW system.

You’ll require dramatically less electricity from the grid, and you should also earn plenty of money by selling your unused electricity via an export tariff.

10kW solar panel system: FAQs