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12 kW Solar Panels UK

In the United Kingdom, solar energy has become a popular and environmentally-friendly option for generating electricity. One powerful configuration for residential and small commercial use is the 12 kW solar system. This system size can produce a significant amount of electricity, helping homeowners and businesses lower their energy costs and reduce their carbon footprint.

A 12 kW solar system generally produces between 900 and 2,000 kilowatt hours per month, assuming at least 5 sun hours per day with the panels facing south. The initial investment for a 12 kW solar system typically costs around £15,000 in the UK, including installation and VAT. With the potential annual savings of around £1,702, it is essential for individuals and businesses to research and compare their options to ensure they make the most out of their solar panel installation.

What Is a 12kW Solar System?

A 12kW solar system is a photovoltaic (PV) system designed to generate around 12 kilowatts of power under optimal conditions. These solar power systems typically consist of a large number of solar panels, inverters, mounting structures, and other components required to convert sunlight into usable electricity.

In the UK, a 12kW solar system has the potential to produce approximately 11,122.26 kWh of energy annually in the South of the UK, depending on factors such as shading, location, roof direction, tilt, and the efficiency of the system components. This power output assumes that the solar panels are operating under ideal conditions, such as clear skies and the optimal angle of sunlight.

A 12kW solar system requires approximately 800 square feet of space for installation. These systems tend to be more suitable for homes or businesses with ample available roof space or land for a ground-mounted installation. When considering a 12kW solar system, it is essential to research various factors, such as the system's efficiency, potential return on investment, and financing options.

Components of a 12kW Solar System

Solar Panels

A 12kW solar system in the UK generally consists of 30 to 75 solar panels, depending on their efficiency. Each solar panel is around 1.6 m², so the total required space ranges between 39 m² and 72 m² 1. These systems are well-suited for larger households and can generate a significant amount of electricity for daily use. It's essential to have sufficient roof space (approximately 75 m²) to accommodate this size of solar installation.


The inverter is a vital component of any solar system, as it converts the direct current (DC) electricity produced by the solar panels into alternating current (AC) electricity that can be used in the home or exported to the grid. For a 12kW solar system, the inverter should be sized accordingly to handle the maximum output. Inverters are also available with various features such as monitoring capabilities, built-in optimisers, and more.

Mounting System

The mounting system holds the solar panels securely in place on the roof or ground, ensuring they remain properly aligned and facing the right direction. A 12kW system will require a robust mounting structure capable of supporting the weight and size of the numerous solar panels involved. It's crucial to choose a mounting system suitable for your specific roof or ground type, taking into account factors like roof material, slope, and local weather conditions.

Battery Storage

While not always included in a 12kW solar system, battery storage can be a valuable addition. It allows the excess electricity generated by the solar panels to be stored and used during periods of low sunlight or high energy demand. Battery sizes and technologies vary significantly, so selecting the right storage solution depends on factors like your daily energy usage, budget, and system configuration. It's worth noting that adding battery storage may increase the cost of a 12kW solar system.

Cost and Savings

Installation Costs

A 12kW solar panel system in the UK can vary in price, with costs commonly ranging from £13,000 to £15,000, including installation and VAT. On average, solar panels cost around £2,246 per kWp installed. Keep in mind that these costs can vary based on the specific equipment and installation factors.

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    Incentives and Grants

    Although there are no direct grants available for solar panel installation, the UK government offers the Smart Export Guarantee (SEG) programme. This allows homeowners to earn money by exporting excess solar energy back to the grid. Various tariffs are available for this programme, and participation often requires metering. To make the best choice, it's important to research your options and consider the available deals carefully.

    Return on Investment

    By installing a 12kW solar system, homeowners can expect to save around £1,702 per year on their energy bills. This number may vary depending on individual consumption patterns and energy prices. It's worth noting that 12kW systems have a relatively quick payback period due to their significant energy output.

    In summary, while initial installation costs may be substantial, the potential savings and return on investment offered by a 12kW solar system make it a valuable addition for homeowners in the UK.

    How Much Energy Does a 12kW System Produce?

    A 12kW solar system can produce varying amounts of energy, depending on factors such as location, shading, roof direction, tilt, and system components. In the South of the UK, a 12kW solar system can produce an average of 11,122.26 kWh annually. Assuming at least 5 sun hours per day with panels facing south, a 12kW system may generate between 900 and 2000 kWh per month.

    The daily energy production of a 12kW solar system would generally range from 45 to 65 kWh. This estimation assumes the panels face south, and the actual energy production may vary considerably based on the factors mentioned earlier. Therefore, it is essential to understand the local environmental conditions to have a more accurate understanding of a solar system's energy production.

    Monthly energy generation would consequently range from 1400 to 2000 kWh, depending on the daily production levels. Bear in mind that each solar panel in a 12kW system can produce approximately 750 watt-hours daily, and with a total of 60 solar panels, the system can generate up to 45,000 watt-hours or 45 kWh per day under optimal conditions.

    In conclusion, the energy production from a 12kW solar system depends on various factors. However, an average 12kW solar system may generate between 45 and 65 kWh daily, roughly equating to 1400-2000 kWh monthly in the United Kingdom.

    Suitable Properties for a 12kW System

    Commercial Properties

    A 12kW solar system is an ideal choice for commercial properties that require a substantial amount of electricity to operate. These systems can generate approximately 11,122.26 kWh annually in the south of the UK, with factors such as shading, location, roof direction and tilt, time of year, and efficiency of components influencing the overall output.

    Commercial properties that could benefit from a 12kW solar system include:

    • Office buildings
    • Retail shops and shopping centres
    • Hotels and restaurants
    • Manufacturing facilities
    • Warehouses

    Installing a 12kW solar system in these commercial properties will not only provide a sustainable energy source but also help reduce operational costs by providing long-term electricity savings.

    Large Residential Properties

    Large households with significant electricity demands may also benefit from a 12kW solar system. Typically, these systems are suitable for homes larger than the average.

    Some factors to consider when installing a 12kW solar system on a large residential property include:

    • Available roof space: A 12kW solar system usually requires approximately 75 m² of roof space.
    • Orientation: The system's efficiency is affected by the direction and tilt of the roof.
    • Local planning regulations: It is essential to check local planning regulations before installing a solar system, as these may vary depending on the region.

    In conclusion, a 12kW solar system is a practical and environmentally friendly option for both commercial and large residential properties. It offers long-term electricity savings and contributes to renewable energy efforts.

    Maintenance and Longevity

    When discussing a 12kW solar system in the UK, it is essential to consider maintenance and longevity for optimal system performance.

    Cleaning and Inspections

    Regular cleaning and inspections are crucial for maintaining solar panels. Ideally, you should have your solar panels cleaned every six months or so, which may cost between £4 and £15 per panel. Inspecting panels to identify wear and tear or any issues can help ensure top performance, minimise downtime and extend the system's useful life.

    Warranties and Guarantees

    A 12kW solar system typically costs around £15,000 in the UK, including installation and VAT. Considering this significant investment, it is essential to be aware of the available warranties and guarantees. Most solar panels are backed by a 25-year performance warranty which guarantees a minimum percentage of power output throughout the course of the warranty. Additionally, manufacturers often provide a 10 to 12-year product warranty for defects and malfunctions. Inverters usually come with a 5 to 12-year warranty, though it can be extended for an additional fee.

    By following the proper maintenance procedures and understanding warranties and guarantees, a 12kW solar system can be a reliable source of renewable energy. Not only does this maximise the system's efficiency and output, but it also extends its lifespan, allowing homeowners to save money and reduce their environmental impact.

    Environmental Impact

    12kW solar panel systems are designed for larger homes in the UK, typically requiring around 75 m² of free roof space for installation. The electricity generated by a 12kW solar system in the South of the UK over a year is, on average, around 11,122.26 kWh. While solar power has been widely adopted due to its lower environmental impact compared to fossil fuels, it's important to understand its potential environmental effects.

    Solar photovoltaic (PV) systems emit approximately 5% of the carbon emissions of coal without carbon capture and storage (CCS) and about 20% of the emissions of coal with CCS. Despite emitting a higher amount of carbon emissions when compared to other renewable energy sources like wind power, solar PV is still considerably more environmentally friendly than conventional fossil fuels.

    The growth of solar power as a significant source of electricity has led to concerns about the materials used in solar panels and their disposal. Solar panels can contain hazardous materials such as lead, arsenic, and cadmium. Proper recycling and disposal of solar panels at the end of their lifespan can significantly reduce the environmental impact of these materials.

    On the other hand, solar power generation effectively reduces dependence on non-renewable energy sources, which translates into a lower carbon footprint for households adopting solar technology. By choosing a 12kW solar system, homeowners can contribute to a more sustainable energy future for the UK.


    A 12kW solar system can be an effective solution for larger homes in the UK, as it generates a significant amount of electricity to meet the daily needs of a sizeable household. However, it is essential to consider the available roof space before installation, as a system of this size generally requires around 75m².

    The cost of a 12kW solar system in the UK, without a battery, is approximately £15,000, including installation and VAT. There may be zero upfront cost options available for those who qualify. It is important to compare quotes and choose a reputable installer to ensure the system's quality and longevity.

    Financially, an investment in a 12kW solar system can be worthwhile, resulting in significant savings on electricity bills. Additionally, environmentally conscious individuals may appreciate the reduced carbon footprint associated with solar energy.

    In conclusion, when considering a 12kW solar system for a UK home, essential factors include the available roof space, quotes from reputable installers, and weighing the long-term financial and environmental benefits. With proper planning, a 12kW solar system can be a valuable addition to a home.

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    Mark McShane
    Content Writer
    Mark McShane is a seasoned professional in the solar industry and the owner of Skills Training Group, a leading provider of solar training and education. With years of experience in the field, Mark has developed a deep understanding of the latest trends, technologies and best practices in the industry. His expertise and passion for solar energy have helped countless professionals develop the skills and knowledge needed to succeed in the fast-growing field of solar energy. Whether you’re an aspiring solar professional or an experienced industry veteran, Mark is an excellent resource for anyone looking to enhance their skills and knowledge of the solar industry.
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