20kW Solar System UK: Complete 2026 Cost Guide

Utility costs can be challenging for homes and businesses, so many find that getting a 20 kW solar system can be advantageous, depending on individual usage and current expenses.

Rising Electric Costs

Electricity tariffs in the UK have been rising higher than inflation, and this is one of the reasons for opting for solar energy. The prices that consumers pay for electricity, which can be evidenced by historical data on Ofgem’s price cap rises, support the financial aspect of solar. Despite the upward trajectory, it’s a perfect business case for getting solar. Given that electricity tariffs are likely to rise in the future, the benefits of having a 20kW system will increase, thus reducing the initial cost outlay.

Smart Export Guarantee (SEG)

The Smart Export Guarantee (SEG) has replaced the older Feed-in Tariff scheme. It allows you to earn money for the excess energy your 20kW solar system generates but does not use. Currently, you can receive up to 15p per kWh of exported electricity. A 20kW solar system could amount to around £1,529 annually, based on typical usage patterns. Octopus Energy offers this rate at the time of writing.

Electricity Savings

A primary motivation for installing a 20kW solar system is the potential savings from using self-generated electricity during the day. This reduces reliance on utility companies and saves money, especially if combined with an electric vehicle. Properly utilized, a 20kW solar system can save approximately £2,836 annually by offsetting electricity costs.

20kw Solar System Price in the UK

The 20kW solar system price (without a battery) is typically around £25,000 in the UK, including installation and VAT. This initial 20kW solar system cost in the UK can quickly be recovered from the long-term benefits. Although AP costs organizations more than some other forms of advertising, it is worth the cost in the long run. Also, different financing and governmental stimulation procedures can make the impact on this front less critical.

How Many Solar Panels for a 20kW Solar System?

Today’s solar panels are between 300W – 500W per panel. Thus, the total number of panels to make up a 20kW solar system would lie in the range of 40 to 74. The number depends on the panel’s efficiency and watts, providing the possibility to be adjusted according to the square footage and price range.

How Big is a 20kW Solar Array?

Each solar panel occupies about 1.6㎡. Consequently, a 20kW solar system would need between 65㎡ and 121㎡ of space, depending on the efficiency of the panels chosen. This range provides options for both residential and commercial properties, accommodating different roof sizes and configurations.

How Much Does a 20kW Solar System Produce? (In the UK)

In the South of the UK, a 20kW solar system produces around 18,537.09 kWh annually. However, several factors influence this output, including:

• Shading
• Geographic location within the UK.
• Roof direction and tilt.
• Time of year.
• Efficiency of the system components.

20 kW Off-Grid Solar System UK

For those considering an off-grid 20kW solar system in the UK, it’s crucial to calculate the required battery size to store the generated energy. You can then purchase the 40 to 74 panels needed for the system. With battery storage, one can use the power generated by this system at night and other times when there is little or no sunlight; hence, efficiency, in addition to costs, is greatly improved. Investigations of the solar panel and battery are crucial in estimating the costs of implantation of an off-grid system.

Electricity cost reduction through the use of a 20kW solar PV system also supports the government’s vision of a reform to a green power economy. The use of heat and power created independently, along with the Smart Export Guarantee, makes it beneficial for those who want to reduce their utilization of regular electricity services and save money. The levelized cost of electricity has risen in the UK, making the 20 kW solar system an attractive option that can provide significant long-term advantages. The inclusion of battery storage, despite adding to the initial solar panels and battery cost, can further enhance savings by ensuring energy availability during non-sunny periods.