Average Solar Panel Output Per Day In the UK

Understanding the average solar panel output per day is essential for homeowners, landlords, and commercial property owners considering an investment in solar energy.

For example, a typical 4kW solar panel system in the UK can generate around 9.32 kilowatt-hours (kWh) of electricity per day under average conditions. That’s enough to cover a substantial portion of a household’s daily electricity needs, depending on usage and efficiency.

In this guide, we’ll break down what affects solar panel output in the UK, from system size to weather conditions and panel efficiency. 

You’ll learn how much electricity various system sizes typically produce per day, how to calculate your potential output, and how this translates to real-world savings.

Key Takeaways

1. Solar panel outputs in the UK vary based on system size, with a 2kW system producing about 4.66 kWh daily and a 4kW system generating around 9.32 kWh daily.
2. Daily solar panel performance is influenced by factors such as geographical location, weather conditions, installation size, and seasonal variations, with significantly higher output during summer months.
3. Monitoring solar panel output is essential for optimising energy efficiency, allowing homeowners to track performance, address issues promptly, and manage energy consumption effectively.

Average Daily Solar Panel Output by System Size - A Quick Overview

How Much Energy Does a Solar Panel Produce?

A typical 350-watt solar panel in the UK produces around 0.84 kWh per day, or approximately 307 kWh per year, under average conditions.

The actual energy output of a solar panel depends on its wattage, efficiency, and your local sunlight exposure. In the UK, panels receive an average of 2.4–3.5 peak sun hours per day, which impacts how much electricity they can generate.

Here’s a breakdown of the most common panel wattages and their estimated daily and annual outputs:

Estimates based on UK solar irradiation data of 850–1,000 kWh/m² per year, assuming optimal installation conditions.

Why It Matters

Higher-wattage panels offer greater output per panel, allowing you to generate more electricity using less roof space. For instance:

• 12 x 350W panels (4.2kW system) = ~10.1 kWh/day
  
• 12 x 400W panels (4.8kW system) = ~11.5 kWh/day

This makes panel selection especially important for properties with limited roof space.

Insights: Need help figuring out your roof’s capacity? Read our guide on how to determine the number of solar panels it can hold. 

Let’s take a closer look at how much electricity you can expect different system sizes to generate per day:

How Much Electricity Does a 1kW Solar Panel System Produce?

A 1kW solar panel system typically produces around 2.4 kWh of electricity per day in the UK. This is based on an average of 2.4 sun hours per day across the year.

• Ideal for: Very small households or properties with limited roof space.
  
• Annual output: Approximately 876 kWh.
  
• Estimated savings: Around £150 per year, depending on your energy tariff.

While uncommon for full household use, a 1kW system may still help reduce electricity costs or power a specific circuit or appliance setup.

How Much Electricity Does a 2kW Solar Panel System Produce?

A 2kW solar panel system can produce approximately 4.66 kWh per day, or around 1,700 kWh per year.

• Ideal for: Small homes, flats, or holiday properties.
  
• Estimated savings: About £290–£320 annually, depending on usage and tariff.
  
• System size: Typically requires 8–10 panels and around 13–15 m² of roof space.

How Much Electricity Does a 3kW Solar Panel System Produce?

A 3kW system produces around 6.99 kWh of electricity per day, adding up to about 2,550 kWh annually.

• Ideal for: Small to medium-sized households with moderate electricity needs.
  
• Roof space needed: Around 20 m².
  
• Estimated savings: Up to £440 per year, depending on energy rates and usage patterns.

This system size strikes a strong balance between space efficiency and energy generation for typical UK homes.

How Much Electricity Does a 4kW Solar Panel System Produce?

A 4kW solar system, one of the most popular choices in the UK generates around 9.32 kWh per day, which equates to 3,400 kWh per year.

• Ideal for: Medium-sized UK households.
  
• System size: Typically 12–14 panels.
  
• Estimated savings: Up to £600 per year, depending on usage and time-of-use tariffs (like Economy 7).

According to the Energy Saving Trust, a system of this size can reduce annual electricity bills by up to £525–£635 depending on your location and self-consumption rate.

How Much Electricity Does a 5kW Solar Panel System Produce?

A 5kW solar system typically produces around 11.64 kWh per day, adding up to roughly 4,250 kWh per year.

• Ideal for: Larger homes with higher daily energy use or properties with electric vehicles.
  
• Roof space: 25–30 m².
  
• Estimated savings: Up to £750–£850 per year, especially if paired with solar battery storage.

How Much Electricity Does a 6kW Solar Panel System Produce?

A 6kW system can generate an estimated 14 kWh per day, or approximately 5,100 kWh annually.

• Ideal for: Large family homes or properties with heavy energy usage.
  
• Estimated savings: Up to £1,000 per year with high self-consumption and smart usage habits.
  
• Good candidate for: Solar batteries or hybrid inverters for energy storage. 

Tip: Thinking about storage? Check out our guide on solar battery costs to get a clear idea of what you can expect to pay.

How Much Electricity Does a 10kW Solar Panel System Produce?

A 10kW solar system produces around 23.29 kWh per day, equalling 8,500–8,900 kWh per year.

• Ideal for: Large properties, commercial buildings, or households with electric heating or multiple EVs.
  
• Roof space required: 50+ m².
  
• Estimated savings: Up to £1,600–£1,900 annually, depending on tariff structure and usage habits.

How Much Electricity Does a 12kW Solar Panel System Produce?

A 12kW system can generate approximately 27.95 kWh per day, or 10,200+ kWh annually.

• Ideal for: Very large homes, multi-family dwellings, or small businesses.
  
• Estimated savings: Well over £2,000 per year with optimal energy management.
  
• Best used with: Battery storage and smart energy usage systems to maximise ROI.

What Factors Determines How Much Electricity Your Solar Panels Produce?

While panel size and wattage give a rough estimate of how much energy you can expect, several real-world factors can influence the actual daily and annual output of a solar panel system.

In the UK, where weather patterns and property types vary widely, understanding these variables is essential for getting the most out of your solar investment.

Below are the main factors that can impact how much electricity your solar panels generate:

1. Sunlight Hours and Geographic Location

The amount of daily sunlight your area receives directly affects your system’s output. For instance:

• Homes in Southern England receive more annual solar irradiance than those in Scotland.
  
• London averages about 3.3–3.6 sun hours per day, while parts of the North average 2.4–2.8 hours.

According to UK Government solar radiation maps, the South West and South East regions tend to be the most solar-friendly.

2. Roof Orientation and Tilt Angle

Solar panels perform best when they face due south at an angle of around 30–40 degrees. This setup allows them to capture the most direct sunlight throughout the year.

• South-facing roofs yield the highest output.
  
• East or west-facing roofs can still be viable but may see 10–20% less efficiency.
  
• Flat roofs require tilted mounting systems to improve exposure.

3. Shading from Trees or Buildings

Even partial shading on a single panel can reduce output across your entire system, especially in older string inverter setups.

Common sources of shading include:

• Trees and nearby buildings
  
• Chimneys or dormers
  
• Satellite dishes or roof-mounted equipment

Modern systems with optimisers or microinverters can reduce shading losses significantly.

4. Panel Efficiency and Quality

Not all solar panels are created equal. The efficiency rating of a panel indicates how much sunlight it can convert into usable electricity. Most UK domestic systems use panels rated between 18%–22% efficiency.

• Higher efficiency = more power per m²
  
• Premium brands (e.g., REC, SunPower) tend to maintain performance longer and degrade more slowly over time

Solar panels from reputable manufacturers often come with 25-year performance warranties, ensuring a certain level of output over time. Take a look at our guide on the most efficient solar panels you can buy in the UK.

5. Temperature and Weather Conditions

Surprisingly, high temperatures can reduce solar panel efficiency. While the UK climate is generally well-suited to solar energy, output may be slightly lower on very hot or overcast days.

• Solar panels operate best between 15°C and 25°C
  
• Performance may drop during heatwaves, though UK losses are typically small

Insights: If you're curious about how extreme heat can affect performance, our article on how high temperatures impact solar panel efficiency offers a deeper explanation.

6. System Size and Inverter Capacity

The total kilowatt (kW) rating of your system determines its maximum potential output, but it’s the inverter that converts DC electricity into usable AC power for your home.

• A mismatch between panel capacity and inverter size can bottleneck output
  
• Ensure your installer sizes the inverter correctly to handle the solar array’s output, especially if you're planning to expand later or add a battery system. For guidance on scaling up your setup, read our guide on adding more solar panels to your existing system.

7. Maintenance and Cleanliness

Solar panels require very little maintenance, but performance can be affected if panels are covered in:

• Dust or dirt buildup
  
• Bird droppings or debris
  
• Snow (less common in the UK but still possible)

A simple clean a few times a year can help maintain optimal energy production. 

How to Maximise the Output of Your Solar Panels

Getting the most from your solar panel system isn’t just about installation, it's about smart usage, optimal setup, and regular upkeep. 

Whether you're already generating solar energy or planning your system, these tips can help you increase performance, boost savings, and extend the life of your investment.

Here’s how you can optimise your solar panel output effectively:

1. Install Panels with the Optimal Orientation and Tilt

In the UK, south-facing panels at a tilt angle of 30–40° produce the most energy year-round. 

If a true south-facing roof isn't available, panels facing south-east or south-west are still highly effective, typically losing only 5–15% of maximum potential output.

If your roof is flat or angled steeply, your installer can use mounting systems to adjust the angle for better solar exposure.

2. Keep Panels Clean and Clear of Debris

Dirt, dust, bird droppings, and leaves can block sunlight from reaching your solar cells, reducing output. While the UK’s frequent rain helps wash away most grime naturally, you should still:

• Inspect panels 2–3 times a year
  
• Hire a professional for safe roof cleaning when needed
  
• Trim nearby trees that may overhang and cause shading

Clean panels can improve efficiency by up to 5–10%, especially in drier months.

3. Minimise Shading on Your Roof

Shade from chimneys, trees, neighbouring buildings, or roof fixtures can drastically reduce output. Even partial shade on one panel can affect the entire system’s performance, especially if you have a string inverter setup.

To reduce shading losses:

• Opt for microinverters or optimisers, which allow panels to operate independently
  
• Work with your installer to conduct a shading analysis pre-installation
  
• Trim or remove obstructions where feasible

4. Schedule Regular Maintenance and Monitoring

Although solar PV systems are low-maintenance, scheduling an annual check-up can help identify issues early and keep everything running efficiently. Things to check include:

• Inverter performance
  
• Panel connections and wiring
  
• Build-up of debris or dirt

You can also install smart solar monitoring apps that track real-time output, detect faults, and help you adjust usage habits for better returns.

5. Use High-Efficiency Panels and Reliable Equipment

Higher efficiency panels generate more power in the same amount of space. If your roof area is limited, investing in premium solar panels (20–22% efficiency range) can significantly boost energy output.

Also, ensure your system includes a high-quality inverter, the heart of your solar setup. Inverters typically last 10–15 years and should be chosen based on both performance and reliability.

6. Pair Your System with a Solar Battery

Installing a solar battery allows you to store excess electricity for use during evenings or cloudy days. This reduces your reliance on the grid and increases your energy self-consumption.

According to the Energy Saving Trust, pairing solar panels with a battery system can double the amount of solar energy you use, especially for households during the day.

7. Use Electricity During Peak Solar Hours

To get the most value from your system, run appliances during peak production times, typically 10 a.m. to 4 p.m. in the UK.

Smart energy habits include:

• Running dishwashers, washing machines, or EV chargers during the day
  
• Using smart plugs or timers to automate energy-heavy tasks
  
• Shifting usage patterns seasonally based on sunlight availability

Frequently Asked Questions

What impact does system degradation have on average solar panel output over time?

Solar panels gradually lose efficiency, typically about 0.5% to 1% per year. After 20 years, most panels still produce around 80–90% of their original output. Factoring in this gradual decline is essential when calculating long-term average daily energy production.

How do different mounting types (roof-mounted vs ground-mounted) affect average solar panel output?

Ground-mounted solar panels can be adjusted more precisely for optimal tilt and orientation, often resulting in higher average daily output compared to roof-mounted systems, which may be limited by roof shape and orientation constraints common in UK properties.

How can smart energy management systems improve the effective use of daily solar panel output?

Smart systems monitor real-time generation and consumption, allowing homeowners to shift energy usage to times of peak production. This optimisation reduces waste and increases the proportion of solar energy consumed onsite, effectively enhancing the value of your average daily output.

Final Thoughts

Understanding the average solar panel output per day in the UK provides valuable insight for homeowners, landlords, and businesses planning to invest in solar energy. 

By considering factors like the number of solar panels you would need, panel wattage, location, and environmental conditions, you can better estimate your potential electricity generation and savings.

Maximising solar output is not just about installing panels; it requires thoughtful system design, routine maintenance, and smart energy use. 

When done right, solar panels can significantly reduce your electricity bills, lower your carbon footprint, and increase your property's value.

With this knowledge, you are better equipped to make informed decisions and partner with trusted suppliers using tools like the Eco Answers Quote-Comparison Tool to find the ideal solar solution tailored to your needs.