Benefit from the BEST Solar Deals in 2024 and SAVE hundreds per year on your bills!
Answer these simple questions and we will find you the BEST prices.
Save hours of research time
Save hours of research time

Get up to 4 quotes by filling in only 1 quick form

Save up to £1,005 per year
Save up to £1,005 per year

Slash your energy bills by installing solar panels

Save the planet
Save the planet

We’ve helped over 500,000 homeowners reduce their carbon footprint

Mentioned in
The Guardian logoHarvard University logoIndependent logoSPACE.com logoForbes logo
Last updated: 31 October 2024

4kW Solar Systems in the UK (November 2024)

4kW solar panel system
  • On average, a 4kW solar panel system generates around 10kWh of electricity per day, 285kWh per month, and 3,400kWh per year.
  • The exact level of energy generated depends on the sunlight hours of the region, the efficiency of the panels, and whether they are facing an optimal direction.
  • You can save up to £660 on your annual electricity bills with a 4kW solar system.
  • A 4kW system consists of 8 (450W) solar panels, which will take up about 16m² of your roof space.

Solar panels are a great way to produce free and renewable electricity for your home, with the 4kW solar panel system producing enough energy to cover the needs of a family of 3 or 4, requiring low maintenance and presenting a very long lifespan, becoming an excellent environmentally friendly option for your home.

In addition, another positive aspect to take into consideration in relation to 4kW solar panel systems is the possibility of exporting back to the grid the electricity surplus it can produce, allowing you to earn money through the Smart Export Guarantee.

Nevertheless, it is also important to understand how efficient this system is and what factors affect its efficiency levels. In this article, we will answer these questions to help you understand the efficiency of 4kW solar panel systems.

You can get up to 4 free, non-binding solar panel quotes from our solar panel suppliers by filling in our quick and easy contact form. Getting several quotes from different installers will enable you to compare prices and choose the one that has the perfect solution for your home. Click the button below to get started.

Get your best deal
Quickly compare 4 FREE quotes
  • Quotes from local engineers
  • Payment by finance available
  • Save up to £1,005 per year

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon
Call us to get quotes
We will get you the best deal

4kW Solar Panel System -Everything You Need to Know

How much electricity does a 4kW solar system produce?

A 4kW solar system typically generates 3,000 - 3,400 kWh of electricity per year in most areas. This can vary depending on factors like location and sun exposure. 

Some other factors that affect the output of solar panels include:

  • Sunlight hours: Areas with more sunlight hours during the day will experience better energy production from solar panels than locations with fewer sunlight hours. 
  • Roof orientation: Installing solar panels on a south-facing roof will result in the highest power output. East or west-facing installations produce less energy (up to 15% less). 
  • Roof pitch: The ideal angle at which solar panels should be installed is 30° to 50°. This allows for optimal energy production all year round. 
  • Shade: Maximising a solar system’s output involves ensuring that there are no sources of shade, such as trees or surrounding buildings, obstructing the sunlight. 

How many panels in a 4kW solar system?

How many solar panels you’ll have in your 4kW system depends on the wattage of the solar panels. Generally, a 4kW system consists of 10 panels (350W) or 8 panels (450W)

It's also good to know that a 4kW system with 10 panels will take up around 20m2 of roof space, whereas 8 panels will require a surface of about 16m2

Number of Solar Panels in a 4kW System
Number of 350W PanelsNumber of 450W PanelsRequired Roof Space
10816 - 20m2

To put these numbers in perspective, it's worth considering that smaller systems, such as a 2kW system require 4 - 5 panels, whereas a larger system, like a 6kW one, consists of 13 - 16 panels. A 4kW system is somewhere in the middle, making it fitting for an average-sized household.

How much money can I save and earn?

A correct number can’t be set as the sun rays that your 4kW solar system will collect will vary throughout the year due to weather conditions. To make sure that you are getting the most out of sunlight, you must consider the placement of the system before installing it.

For instance, the angling of your roof can increase or decrease the solar panel efficiency, if your roof is completely North facing your panels will have significantly reduced capabilities. Remember that if you want to increase your earnings, you will have to save energy. Don’t leave all appliances working or on standby when you are not using them.

For the installation, you will need 28 m2 of free roof space and around £5,000 - £6,000 (price may also vary depending on the supplier you choose) for the purchase and installation. The first year you are looking at around £660 return, which means that the system will pay for itself in approximately 8 years and for a 25 year period you are looking at savings of around £16,500.

This is why solar panels are worth it. For larger solar systems like 4kW, 5kW or 6kW solar systems with battery in the UK, these numbers will be even larger.

However, worth noting there are also low cost solar panels to choose from. While they can significantly help you save on the initial investment, the efficiency of these panels is way lower, reaching usually 18—22%. 

You can also minimise your energy savings by using energy at night with the help of a solar battery. The average Lithium solar battery size for a 2 to 3-person household is between 10kWh to 20kWh. Check out our comprehensive reviews of various manufacturers and see our candidates for the best solar battery storage in the UK if you want to learn more.

The Feed-In Tariff

The tariff was a government incentive introduced with the purpose of inspiring people to go solar. On average, you can expect to earn around 4p for each kWh produced and used, according to Ofgem.

The extra electricity that you simply don’t use but export back to the grid will earn you around 2p and your energy bills will be reduced significantly.

In order to receive the money from FiT your supplier must be MCS certified. This scheme closed in 2019, though the installations registered under the FiT will continue to receive payments.

The Smart Export Guarantee

This scheme was newly introduced in 2019, after the closure of the FiT. Under the Smart Export Guarantee (SEG), UK homeowners can receive payments from their energy suppliers when they export surplus energy back to the grid. This will help you recover some of the installation cost of solar panels.

Solar energy suppliers with over 150,000 domestic customers are obliged to offer at least one export tariff - though the tariffs are not yet regulated by the government. The average price of the tariff would be between 5-6p per kWh exported.

To be eligible, you need a small-scale low-carbon electricity generator, such as a 4kW solar system. Your installer must also be MCS-certified, which means that many DIY solar panels in the UK are not eligible without proper assessment.

Benefits of investing in a 4kW solar panel system

Are you in doubt whether it is a good idea to invest in a solar power system? It is true that buying 4kW solar panels implies a considerable investment, but this will guarantee that you will produce your own and clean energy, and will also save money in the future. As with any big investment, one should think of solar panels from a long-term perspective

benefits of investing in a 4kW solar panel system

Even though it is cheaper today to pay your bills and get electricity from the national grid, this will not remain the same in the future. Firstly, because the price of fossil fuels will undoubtedly grow, therefore pushing the prices of electricity produced from such sources.

Secondly, as more people are switching to green energy, economies of scales are leading to lower prices in the respective technologies. In the next few years, solar panels will be cheaper, and more effective.

Additionally, as governments are pressured to take actions in order to tackle climate change, there are many incentives and solar panel grants that make green investments financially convenient. 

How to maximise efficiency of your 4kW panels 

Installing a solar panel system should not be a hassle. There are some things you can do to make sure you will make the most out of your 4kW solar panel system. This includes not only where you place the 4kW solar panels (away from any sort of shade) but also making sure that your home is energy efficient.

Sometimes this factor is underestimated, but having a well-insulated home will for sure lead to better results when incorporating any type of renewable source of energy!

  • You need to make sure your home is suitable for the installation (having good insulation is usually enough). This will determine how many solar panels you need in order to cover your energy demands.
  • South-facing roofs are perfect, but east or west-facing ones produce only up to 15% less energy.
  • You will need from 21 m2 to 28 m2 roof space for a 4kW solar system. Solar panel installers will typically ask you how big your roof is as a first thing.
  • Make sure nothing is shading over your roof. The power output of a solar array is proportional to the energy it receives from the sun. If the panels are blocked with shade, then the energy they can convert into electricity will be limited.

Get quotes on 4kW solar panel systems

It might seem to you that solar panels are too complex for you to make a choice all by yourself. With the vast amount of technical details, it always helps to talk to an expert and get a recommendation and personalised quote from them.

Fill in our easy form to receive up to 4 tailored quotes from our solar panel supplier partners. This service is provided for free and without any obligations. They will give you customised quotes based on your needs and preferences so that you can find the deal that you have been looking for. Start by simply clicking the button below.

Get your best deal
Quickly compare 4 FREE quotes
  • Quotes from local engineers
  • Payment by finance available
  • Save up to £1,005 per year

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon
Call us to get quotes
We will get you the best deal