Solar panels in the UK — how they work and what they cost in 2026

# Solar panels in the UK — how they work and what they cost in 2026 Solar panels have become an increasingly popular choice for UK homeowners looking to reduce their electricity bills and carbon footprint. Despite Britain's reputation for cloudy weather, modern solar technology can generate significant electricity even in our climate. This guide explains everything you need to know about solar panels in 2026. ## How solar panels work — the basics Solar panels convert sunlight into electricity through photovoltaic (PV) cells, typically made from silicon. When photons from sunlight hit these cells, they knock electrons loose, creating an electric current. This process, known as the photovoltaic effect, works even on cloudy days as solar panels can capture diffused light. The electricity generated by solar panels is direct current (DC), but your home uses alternating current (AC). An inverter converts the DC electricity into AC electricity that can power your appliances or be fed back into the national grid. A typical domestic solar installation includes: - Solar panels (the photovoltaic modules) - An inverter system - Mounting equipment for roof or ground installation - Electrical connections and safety equipment - A generation meter to track electricity production ## Types of solar panels There are three main types of solar panels available for domestic installations in the UK: ### Monocrystalline panels Monocrystalline panels are made from single-crystal silicon, giving them their distinctive dark blue or black appearance. They offer the highest efficiency rates, typically 18-22%, making them ideal for homes with limited roof space. These panels perform better in low-light conditions compared to other types, which is advantageous in the UK climate. The main benefits include higher power output per square metre and better performance in partial shading. However, they tend to be more expensive than other options. ### Polycrystalline panels Polycrystalline panels are made from multiple silicon crystals melted together. They have a distinctive blue colour with visible grain patterns. While slightly less efficient than monocrystalline panels (typically 15-17%), they offer good value for money. These panels are suitable for most UK installations where roof space isn't severely limited. They tend to be more affordable whilst still providing reliable electricity generation. ### Thin-film panels Thin-film panels are made by depositing photovoltaic material onto a substrate such as glass or metal. They're flexible and lightweight but have lower efficiency rates (10-13%) compared to crystalline panels. This means you need more roof space to generate the same amount of electricity. Thin-film panels can work well in some specific situations, such as curved surfaces or where weight is a concern, but they're less common in UK domestic installations. ## How much electricity will they generate Solar panel output in the UK varies depending on location, orientation, and shading. The key measurement is kilowatt-hours (kWh) generated per kilowatt-peak (kWp) of installed capacity annually. In the UK, you can typically expect: - Southern England: 950-1,050 kWh per kWp annually - Central England: 850-950 kWh per kWp annually - Northern England and Scotland: 750-850 kWh per kWp annually These figures assume optimal conditions with south-facing panels at a 35-degree angle with minimal shading. East or west-facing installations typically generate 10-15% less electricity, whilst north-facing installations are generally not recommended. Monthly generation varies significantly, with summer months producing 4-5 times more electricity than winter months. July typically sees peak generation, whilst December and January produce the least. ## How many panels do I need — sizing guide The number of solar panels you need depends on your electricity consumption, available roof space, and budget. Here's a general sizing guide: **Small system (2-3kWp):** 6-10 panels - Suitable for low electricity users (2,000-3,000 kWh annually) - Generates approximately 2,000-2,700 kWh annually - Requires 12-20 square metres of roof space **Medium system (4-5kWp):** 12-16 panels - Good for average households (3,500-4,500 kWh annually) - Generates approximately 3,400-4,500 kWh annually - Requires 25-35 square metres of roof space **Large system (6-8kWp):** 18-24 panels - Suitable for high electricity users or those with electric vehicles - Generates approximately 5,100-7,200 kWh annually - Requires 40-55 square metres of roof space To calculate your needs more precisely, review your annual electricity consumption from recent bills. A well-sized system should generate 80-100% of your annual electricity usage, though you'll still need grid connection for times when panels aren't generating enough power. ## Typical installation costs Solar panel installation costs have decreased significantly over recent years, though prices vary by location and installer. Several factors influence the total cost: **System size:** Larger systems benefit from economies of scale, with per-kWp costs typically reducing as system size increases. **Panel type:** Monocrystalline panels cost more than polycrystalline options, whilst thin-film panels vary depending on the specific technology. **Roof complexity:** Simple installations on straightforward roofs cost less than complex installations requiring additional scaffolding or structural work. **Location:** Installation costs can vary between different regions of the UK, with urban areas sometimes commanding higher prices due to increased demand and operating costs. **Additional equipment:** Battery storage, optimisers, or upgraded inverters increase overall system costs. The overall investment should be considered alongside potential savings on electricity bills and income from the Smart Export Guarantee scheme. ## Smart Export Guarantee — selling excess power The Smart Export Guarantee (SEG) allows you to sell excess electricity generated by your solar panels back to the grid. All licensed electricity suppliers with 150,000+ customers must offer SEG tariffs, whilst smaller suppliers can participate voluntarily. SEG rates vary between suppliers and tariff types: - **Fixed rate tariffs:** Offer a set price per kWh exported - **Variable rate tariffs:** Prices can change over time - **Time-of-use tariffs:** Different rates for different times of day To benefit from SEG, you need: - An MCS-certified solar installation - A smart export meter to measure electricity sent to the grid - To sign up with a SEG licensee (this can be different from your electricity supplier) The amount you can earn depends on your system size, electricity consumption patterns, and the SEG rate. Households typically export 30-50% of generated electricity, though this varies significantly based on when electricity is used. ## Payback period in UK conditions The payback period for solar panels in the UK depends on several factors including system cost, electricity savings, and SEG income. Most domestic solar installations achieve payback within 8-12 years. **Factors affecting payback time:** **Electricity consumption patterns:** Households that use more electricity during daylight hours see faster payback as they use more generated electricity directly rather than exporting it. **Electricity prices:** Higher electricity rates improve the financial return from solar panels by increasing savings on purchased electricity. **SEG rates:** Higher export rates improve payback times, though this income typically represents a smaller portion of total benefits. **System performance:** Well-designed and maintained systems achieve better returns through consistent electricity generation over their 25+ year lifespan. After the payback period, solar panels continue generating electricity and savings for many years. Most panels come with 20-25 year warranties and can produce electricity for 30+ years with gradual performance degradation. ## Planning permission and building regulations Most domestic solar panel installations in England, Scotland, and Wales fall under permitted development rights, meaning planning permission isn't required. However, there are specific conditions: **Permitted development conditions:** - Panels shouldn't protrude more than 200mm from the roof surface - No panels on walls facing a highway if the property is in a conservation area - Removal of panels should restore the building to its original condition - No panels on listed buildings without specific consent **Building regulations typically don't apply** to straightforward solar installations on existing buildings. However, you may need building regulations approval for: - Structural modifications to support heavy panel arrays - Significant electrical work beyond the installation scope - Ground-mounted systems requiring foundations **Special considerations:** - **Listed buildings:** Always require consent for solar installations - **Conservation areas:** May have additional restrictions - **Flats and communal areas:** May need freeholder permission - **New builds:** Must comply with building regulations during construction Always check with your local planning authority if you're unsure about requirements for your specific property and location. ## FAQ **Do solar panels work in winter?** Yes, solar panels work year-round in the UK. While generation is lower in winter months due to shorter days and lower sun angles, panels still produce electricity on clear winter days. Snow typically slides off angled panels quickly and can actually increase generation through reflection. **How long do solar panels last?** Quality solar panels typically last 25-30 years or more. Most manufacturers provide 20-25 year warranties guaranteeing at least 80% of original performance after this period. The inverter may need replacement after 10-15 years. **Do I need battery storage?** Battery storage isn't essential but can increase the financial benefits of solar panels by storing excess electricity for use when panels aren't generating. Batteries add significant cost to installations but can provide backup power during outages. **What maintenance do solar panels need?** Solar panels require minimal maintenance. Occasional cleaning to remove dirt, leaves, or bird droppings helps maintain performance. Annual visual inspections can identify any issues early. Most systems include monitoring to track performance. **Can I install solar panels myself?** While technically possible, solar installations should be carried out by qualified professionals for safety and compliance reasons. DIY installations typically void warranties and may not qualify for SEG payments or insurance coverage. **Will solar panels damage my roof?** Properly installed solar panels shouldn't damage your roof. Professional installers assess roof condition before installation and use appropriate mounting systems. Panels can actually protect the roof area they cover from weather exposure. Finding the right installer is crucial for a successful solar installation. Our directory includes qualified installers across the UK, with particular strength in major cities including London, Bristol, Manchester, and Glasgow. Most featured installers hold MCS certification, ensuring they meet recognised industry standards for solar installations. When choosing an installer, look for relevant certifications such as MCS, RECC, or NAPIT accreditation. These ensure installers meet professional standards and can provide installations eligible for government schemes like SEG. [Search our directory](/) to find certified solar installers in your area and compare quotes for your solar panel installation.