4kW Solar Panel System Guide and Costs

A typical 4kW solar panel system will generate savings of £8,080 over 20 years and cost around £6,000. That’s a return on investment of over £2,000.

A 4kW system is the most popular size for residential solar panels and will deliver a healthy return on your investment.

You can compare prices of leading 4kW systems by completing the form at the top of this page.

4kW solar pv systems

4kW solar systems are one of the most popular system sizes for residential installations.

A 4kW solar panel will typically cover the energy requirements of a family home of 4 people.

A typical 4kW solar system will require about 24 to 28 square meters of shade free roof space.

If you have limited roof space it is possible to get a high efficiency 4kW system which would require less space, although this will be more expensive.

How much will I make with a 4kW system?

How will I save and earn money?

Installing solar panels allows you to save and earn money in three ways:

1. Energy Bill Savings
As you are producing free energy which you can use to power your own home, you will make significant savings on your energy bills; you can expect solar panels to reduce your electricity bills by 50% on average.

2. Generation Tariff
The Generation element of the Feed-in Tariff pays you for all the electricity you produce regardless of whether you use it to power your home or not. These payments last for 20 years and are the main reason why solar panels are so profitable.

3. Export Tariff
The Export Tariff element of the Feed-in Tariff theoretically pays you for all the electricity you don’t use which automatically goes back into the power grid. However unless your home has a smart meter, you will receive Export payments for 50% of all the electricity you generate as it’s impossible for energy companies to monitor. This means that even if you use all the electricity you generate you will still receive export payments. These payments last for 20 years.

What is the current Feed-in Tariff rate for 4kW?

The table below shows the current Feed-in Tariff rate as well as future rates confirmed by the government.


Generation Tariff for <10kW (p/kWh):
Q1 2016
Q2 2016
Q3 2016
Q4 2016
Q1 2017
Q2 2017
Q3 2017
Q4 2017
Q1 2018
Q2 2018
Q3 2018
Q4 2018
Q1 2019

How much will I earn?

The table below shows typical earnings from a 4kW system compared to other popular residential sizes:

Typical System Size:
Estimated First Year Return:
Profit Over 20 years:

The Feed-in Tariff gets reduced every quarter. If you are considering solar panels don’t wait too long as you will want to qualify for the current higher Feed-in Tariff rate.

Once you register your panels, you are locked in at that rate for the entire 20 years of the Feed-in Tariff. Click here to learn more

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How much does a 4kW solar panel system cost?

The table below shows the typical price of a 4kW system compared to other residential sizes:

Typical System Size:
Estimated Cost (£):
Estimated First Year Return:
Profit Over 20 years:

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Compare Prices of 4kW Solar Systems

Is a 4kW system right for me?

Qualifying for the highest payout from the Feed-in Tariff, a 4kW is a popular and profitable system size for residential solar panels.

When talking to the solar installers you receive quotes from, it is always worth discussing what size would be best for your circumstances.

Generally speaking, if you have adequate roof space and use a medium or high amount of electricity a 4kW system will deliver a high return on your investment.

You might also want to consider a 5kW system if you have plenty of roof space. Even though it qualifies for a lower Feed-in Tariff band, the extra energy produced is likely to earn you more money overall. The installation costs are likely to only be a few hundred pounds more than a 4kW system so over 20 years your return on investment could be higher.


Key points to remember when installing a 4kW solar panel system:

- You will typically need 24 to 28 square meters of free roof space.

- This roof space will need to be shade free for the majority of the day to get the best results.

- You will also need a small amount of space (normally in the attic) for your inverter. This converts the sun’s light into the energy you will use.

- Before your installer installs the panels they are required to complete a survey of your roof structure to ensure it is suitable for solar panels. The vast majority of roofs in the UK can comfortably support the weight of solar panels, but installers are legally obliged to check.

- You will get the best results for South, South-West and South-East facing roofs. West and East facing roofs will still deliver acceptable yields.

- To qualify for the Feed-in Tariff scheme you will need to use an MCS accredited installer.

Finding the best price

It is recommended that you compare quotes from at least 3 or 4 MCS accredited installers to ensure you get the best price. Always ensure that the quote breaks down the different elements of the quote.

You can join the thousands of homeowners who have used The Eco Experts to compare prices from up to 4 local and trusted MCS accredited installers. Simply enter your postcode at the top of this page to begin. This is a completely free comparison tool which helps you find the best price.

Compare Prices of 4kW Systems

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