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Why get solar panels?

  • Generate free, green electricity
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3 kW solar panel system: Is it right for your home?

3 kilowatt solar panel systems cost around £6,022

Two- and three-bedroom homes are best suited for 3 kW systems

A 3 kW solar panel system will generate around 2,267 kWh per year

Depending on size of residential solar PV system you get, solar panel costs typically range between £4,216 and £9,837. 

A 3 kilowatt (kW) solar panel system is likely to suit medium-sized homes, usually with between two and three bedrooms. Typically, these solar panel systems cost around £6,022 to install.

Want to find out more about 3 kW solar panel systems? This helpful guide covers everything you’ll need to know about them, including how many panels you’ll need, how much electricity they can generate, if it’s a good idea to get a solar battery with them, and whether you can go off-grid with a 3 kW system.

It’s simple to compare solar panel prices too, with our help. Just enter a few details about your home in the form, and our expert installers will get in touch with bespoke quotes for you to compare.

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Man installing solar panels on a roof

What is a 3 kW solar panel system?

A 3 kW solar panel system has a power output of three kilowatts, which can generate roughly 2,260 kilowatt hours (kWh) of electricity per year. That’s about the same as the average electricity consumption of a large two-bedroom house, or a smaller three-bedroom home.

If your home is slightly bigger than this, a 4 kW solar panel system might suit you better.

3 kW solar panel systems work just like any other set up — they convert sunlight into clean electricity, so you can power your home without relying on the grid as much.

A 3 kW solar panel system might not be enough to fully power your home, but it’ll reduce your grid reliance by a lot. Your carbon emissions will shrink too, saving the average three-bedroom house 0.6 tonnes of CO2 every single year.

You can find out more about solar panel costs by visiting our detailed guide.

How many solar panels are in a 3 kW solar system?

If each solar panel has a power rating of around 350 watts there will be between eight and nine solar panels in a 3 kW system.

You could even end up having fewer than this if you opt for monocrystalline solar panels. These generate up to 20% more energy per square foot than other types of solar cells, making them one of the most efficient types of solar panels you can get.

This means they’ll take up less space to generate the same amount of energy as a larger polycrystalline solar panel system.

You can also get a 3 kW system using thin-film solar panels, although they use up more space to achieve a 3 kW output because thin-film panels are generally less efficient than regular panels.

Our article on how many solar panels you’ll need is a great way to find out how big your system should be.

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What’s the average price of a 3 kW solar system?

Expect to pay an average of £6,022 for a 3 kW solar panel system, which is roughly £703 per panel.

This price includes installation, but be aware that solar panel costs vary, depending on who you choose to install your system and the type of panels you go for.

It’ll typically take the average homeowner around 14.55 years to break even on a 3 kW solar panel system, and they’ll make around £414 profit from savings and selling excess electricity to the grid via the Smart Export Guarantee (SEG).

Solar panels on a red roof

How much electricity can a 3 kW solar system produce?

A 3 kW solar panel system will generate around 2,267 kWh per year, or around 6.2 kWh per day.

The amount of electricity your solar panel system generates each day will differ, depending on weather conditions — bright, sunny days are often better for solar panels, which means they’ll produce more electricity.

However, you should note that a 3 kW solar panel system will still work even when the sun isn’t shining, just not quite as well. Under light cloud cover, solar panel efficiency drops by roughly 23%, and under heavy cloud cover, it falls by around 66%.

So you might need to fall back on the grid if you’re using lots of appliances during these times, but typical usage, such as powering lights, a fridge, and a television, will continue to draw electricity from your solar panels.

Could you have a 3 kW off-grid solar system?

A 3 kW solar panel system won’t usually be able to power a complete off-grid setup, but it will still help you reduce the amount of electricity you use from the grid.

You could go off-grid with a battery system by combining it with more than just solar panels – for example, you could add a small wind turbine to your setup. But even with this, you’d struggle to power all the appliances in a typical household.

You’ll also need to make sure your electricity consumption each day is less than the typical daily power output of 6 kWh, which is what a 3 kW solar panel system would produce. Again, adding another renewable energy source to your setup will help with this, but it’s not a guarantee.

This is because there’ll be days when your solar panels won’t benefit from optimal conditions, and will generate less electricity than on a day with lots of sunshine.

Going off-grid with a 3 kW solar panel system and a battery will cost you around £15,022. This covers one solar panel system, plus two solar batteries throughout the system’s typical 25-year lifespan.


A 3 kW solar panel system is an ideal size for a large two-bedroom property or a small three-bedroom home, with an average electricity consumption of 2,200 kWh per year.

Owning solar panels will shrink your energy bills and your carbon emissions – you’ll be powering your home with clean electricity generated using the power of the sun. That’s a result for your finances and the planet.

Want to start comparing solar panel prices? We can help — simply enter a few details about your home in the form and we’ll put you in touch with our expert suppliers. They’ll contact you with bespoke solar panel quotes for you to compare.

Written by:
Tom Gill
Tom joined The Eco Experts over a year ago and has since covered the carbon footprint of the Roman Empire, profiled the world’s largest solar farms, and investigated what a 100% renewable UK would look like. Tom has a particular interest in the global energy market and how it works, including the ongoing semiconductor shortage, the future of hydrogen, and Cornwall's growing lithium industry.
Reviewed by:
Tamara Birch, senior writer, The Eco Experts
Tamara has written about environmental topics for more than four years. This includes advising small business owners on cost-effective ways, like solar panels and energy-efficient products to help them become more sustainable. 
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