If you're researching solar for your home, one of the first questions is usually: how much electricity does a solar panel produce in the UK?
The answer depends on panel wattage, roof direction, shading, location, and overall system size. As a rule of thumb, a typical 350W solar panel generates around 260–270 kilowatt hours kWh per year in UK conditions, while a well-designed 4kW solar array often produces roughly 3,400–4,200 kWh annually. For context, Ofgem says a typical household in Great Britain uses around 2,700 kWh of electricity per year, so a correctly sized system can make a meaningful dent in electricity bills.
Solar is also playing a much bigger role nationally than it used to. UK solar generated about 5% of electricity in 2024, showing how quickly the technology has grown and why more homeowners are now looking seriously at long-term solar savings.
Quick answer
Here are the figures most homeowners want first:
- A 350W panel typically generates around 260–270 kWh per year in the UK.
- A 1kW system often generates around 850–1,000 kWh per year.
- A 4kW system usually generates about 3,400–4,200 kWh per year.
- A standard domestic system is often around 10 to 14 panels, depending on panel wattage and available roof space. This follows from typical modern panel sizes of roughly 300W–450W and standard residential system sizes around 4kW.
- 2kW system: around 1,700–2,000 kWh per year
- 3kW system: around 2,550–3,000 kWh per year
- 4kW system: around 3,400–4,200 kWh per year
- 5kW system: around 4,200–5,000 kWh per year
- Low-usage homes: may suit a 2kW system
- Average homes: often look at 3kW to 4kW
- Larger or higher-usage homes: may need 5kW+
- your tariff
- your daytime usage pattern
- your system size
- whether you have a battery
- how much of your solar generation you self-consume
- you have a decent amount of usable roof space
- you have a south facing roof or near-south orientation
- you are home during the day, or add battery storage
- you are thinking long term about energy costs
What do watts, kilowatts and kilowatt-hours mean?
This is where a lot of solar content gets confusing, so it helps to keep the terms simple.
Watt (W) This is the rate of power output. If a panel is rated at 350W, that is its peak output under standard test conditions.
Kilowatt (kW) One kilowatt equals 1,000 watts. A 4kW system is simply 4,000W of installed solar capacity.
Kilowatt hours kWh This is the actual amount of electricity generated or used over time. Your electricity bill is measured in kWh, and solar generation is too.
In other words, panel wattage tells you the size of the system, while kWh tells you the energy production you can expect over a day, month, or year.
How much electricity can one solar panel produce?
A single solar panel's annual output depends on its wattage and the site conditions.
In the UK, modern residential panels in the UK are commonly around 300W to 450W. A typical 350W panel will generally generate about 260–270 kWh per year, though the true figure can be lower or higher depending on solar irradiance, shading, roof pitch, and orientation.
That means one panel alone will not run an entire home. Solar works as a combined system, with multiple panels forming a solar array sized to match your household's energy consumption.
How much electricity does a full solar system produce?
Most homes do not install just one panel. They install a system sized to their property and usage.
Typical residential system sizes in the UK often range from 2kW to 6kW. A rough guide looks like this:
For many homes, a 4kW system is the sweet spot because it offers a strong balance between available roof space, upfront cost, and annual electricity production.
How many solar panels do I need?
The number of panels depends on two things: your annual energy consumption and how much usable roof area you have.
If your home uses close to the Ofgem typical electricity figure of 2,700 kWh per year, a system around 3kW to 4kW may be a sensible starting point, depending on how much of your daytime electricity usage you want solar to cover.
As a very rough guide:
With current panel wattages, a standard 4kW installation often works out at around 10 to 14 panels. Higher wattage, high efficiency panels can reduce the number of panels needed for the same total system size.
What affects solar panel output?
No two homes generate exactly the same amount. Several factors affect how much electricity a solar panel produces.
1. Roof direction
A south facing roof usually delivers the best performance in the UK because it receives the most consistent daylight across the day. Energy Saving Trust notes that solar panels work best on a south-facing roof with little or no shade. East- and west-facing roofs can still work well, but they typically generate less overall.
2. Solar irradiance and location
Solar irradiance refers to how much solar energy reaches a given area. Southern parts of the UK generally receive more solar resource than northern areas, so the same system in Hampshire will usually outperform the same system further north.
3. Shading
Trees, chimneys, neighbouring properties and roof features can all reduce output. Even partial shading can have a noticeable effect on overall energy production, especially on systems using standard string inverter setups. Energy Saving Trust specifically highlights shading as a key performance factor.
4. Panel efficiency
Higher-wattage, high efficiency panels generate more electricity from the same amount of roof area. This matters if your roof space is limited and you need to maximise output per square metre. Energy Saving Trust notes that installation size and panel performance both influence generation and savings.
5. Time of year
Solar output changes significantly across the seasons. Summer gives longer daylight hours and stronger generation, while winter output is much lower. Panels still work on cloudy days, but yearly output is always weighted more heavily toward spring and summer.
6. Maintenance and system design
A well-designed system with good inverter performance, minimal shading and sensible panel placement will outperform a poorly planned one. Dirty panels and unresolved faults can also reduce power output over time.
Which panels produce the most electricity?
In general, monocrystalline panels are the most common choice for homes because they offer strong efficiency and better output per square metre than older polycrystalline designs. Energy Saving Trust notes that modern solar panels have become increasingly effective and practical for UK homes, while typical domestic systems are designed around making the best use of available roof area.
For most homeowners, the key point is not chasing a brand name for the sake of it. It is choosing a panel and system design that fit your property, budget, and long term energy goals.
How much can solar cut electricity bills?
Solar can reduce electricity bills, but the actual saving depends on how much electricity you use during the day and whether you add battery storage.
If you generate electricity and use it in real time, you avoid buying that electricity from the grid. That is where the most obvious bill reduction comes from. Export tariffs can also add value for unused electricity sent back to the grid. Energy Saving Trust notes that solar panels can lower bills by generating electricity for your home directly.
The exact saving will depend on:
Is solar worth it in the UK?
For many homes, yes. Solar panels in the UK still generate meaningful electricity even though we do not have Mediterranean weather. They work with daylight rather than heat, and official consumer guidance continues to support solar as a practical home energy measure, especially on unshaded roofs with suitable orientation.
The value is usually strongest when:
How to get a more accurate estimate
The best way to find out what your home could generate is to speak to experienced solar panel installers who can assess your roof, shading, location and annual usage properly.
At CRG Direct, we help homeowners understand the real-world amount of electricity a solar system could produce for their property, not just generic national averages. A properly sized solar array should match your household's needs, available roof area and budget, while giving you the strongest possible return through reliable electricity production and lower energy bills.