Get up to 4 quotes by filling in only 1 quick form
Slash your energy bills by installing solar panels
We’ve helped over 500,000 homeowners reduce their carbon footprint
Before installing solar panels for your home, there is one key question you should ask yourself, namely: How many solar panels do I need? The average 1 to 2 bedroom house will need 5 to 8 panels at 350W capacity each while a 2 to 3 bedroom home will require 10 to 13 panels. Larger homes would require 16+ panels, but this can vary based on numerous factors.
Every home is different, however, so your situation might vary. To find a more specific answer and make use of the many benefits of solar energy, you will want to consider your daily energy consumption, the number of sun hours in your area, and the size of your roof. If you’re wondering, “How big of a solar system do I need?” this page will help answer that, both in terms of capacity and physical dimensions.
However, you might find that even after learning more about how solar panels work, you still need some assistance determining just how many you need. Finding a reliable installer who can help you can be a daunting task that can lead to hours of research without a guarantee that you will get any fruitful results. To help you avoid wasting your time, we can put you in touch with solar panel installers vetted by us!
By clicking below, you can fill in our 30-second contact form and receive quotes from up to 4 trusted solar experts in your area. With multiple options, you can choose the installer you want to work with and find the best deal. All quotes are completely free and non-binding, so click the button below to get started.
It only takes 30 seconds
To calculate the number of solar panels you need, first determine your annual electricity consumption in kilowatt-hours (kWh). An average average UK household consumes about 2,900 kWh annually.
Solar panels’ output varies by model but assume an average production of 350 watts per panel under optimal conditions.
Therefore, to cover a medium-low consumption profile (1,800 kWh/year), you’d need approximately 6 solar panels. For medium usage (2,700 kWh/year), 9 panels would suffice. Households with medium-high consumption (4,100 kWh/year) should consider 13 panels.
Keep in mind that these estimates are based on average conditions and actual needs may vary based on your location’s sunlight exposure, the panels’ efficiency, and your household’s energy consumption. As the number of residents increases, so do the energy consumption levels and solar panel sizes.
You can consult the table below for an idea of the number of solar panels required to power homes of different sizes.
House size | Annual energy consumption | Number of solar panels (350W) | Number of solar panels (450W) |
---|---|---|---|
1-2 bedroom | 1,800kWh | 6 | 5 |
2-3 bedrooms | 2,700kWh | 9 | 7 |
4-5 bedrooms | 4,100kWh | 13 | 10 |
The average number of solar panels will also be determined by whether you would like your solar panels to generate all your electricity needs or only a percentage.
A medium-sized UK home typically consumes 2,700kWh of energy annually and some UK homeowners use solar energy to power only parts of their energy consumption, which would then reduce the number of solar panels installed.
The image below is based on 350W panels.
To calculate what solar system size you need, you should first know the amount of energy that you need to generate from your solar system daily. The other important things are the sun hours in your area and your roof space, as this can help you determine how many solar panels your roof can accommodate.
If you’re wondering “How many solar panels can I have on my roof?”, you can use 2m2 per panel as a general rule of thumb and see how many you can fit on your roof space.
Generally in the UK, about 8 solar panels of 350W each are needed for a 3kW solar panel system, and usually 16 panels for a 6kW installation. Overall, the bigger the size of the panel system, the more energy is generated per square metre.
Size of solar system | Number of 350W panels | Estimated surface area |
---|---|---|
3kW | 8 | 16m² |
4kW | 10 | 20m² |
5kW | 13 | 26m² |
6kW | 16 | 32m² |
To find out how many you need to install on your roof, you can check your monthly energy bills. These can provide information on the amount of energy that you consume per day, and therefore how much energy you need your solar panels to generate daily. You can follow the same process to find the right commercial solar panel system size if you want to invest in solar PV for your business.
Naturally, cost is an important determining factor for how many solar panels you need. The cost of solar panels in the UK depends on several factors including the size and type of solar panels. The cost ranges from £7,000 to £17,000 for solar panel system sizes ranging from 3 kW to 12 kW solar systems in the UK.
You can find an estimation of prices per solar panel system size in the table below:
Solar panel size | Number of 350W Panels | Price | Break-even point (years) |
---|---|---|---|
3kW | 8 | £7,000 – £8,000 | 14 |
4kW | 10 | £9,000 – £10,000 | 12 |
5kW | 13 | £11,000 – £12,000 | 15 |
6kW | 16 | £12,000 – £13,000 | 11 |
Other factors that may affect the cost of solar panels include:
To determine the size of the panels that you need for your house, you need to know the following:
It is important to be aware that different regions in the UK have different sun hours per day: England has 4.1, Scotland has 3.7, Northern Ireland 3.2 and Wales 3.3. This means that it could be more beneficial to install solar panels in Scotland, compared to solar panels in Northern Ireland. It is therefore important that you consult your local installer for guidance. This could result in bringing down the solar panel price in Wales, England, Scotland or Northern Ireland.
Solar panels generate different amounts of energy depending on their wattage size or rating. A 350 watt panel will generate up to 350 watts per sun hour while a 400 watt solar panel can generate up to 400 watts per sun hour (under ideal conditions). This is why it is important to know the amount of energy you need before determining solar panel sizes.
South-facing roofs with a slight tilt towards the West perform the best in the UK. Countries such as Australia will require solar panels facing in the opposite direction. There are minute differences throughout the UK, but this rule generally applies throughout the region.
The most optimal angle for solar panels is between 30° to 50° as well. It is recommended to adjust the angles throughout the year to accommodate the changing position of the sun.
How much space you have on your roof is also a major consideration. Solar panels are light enough to rest on roofs without any damage. That said, not every section of your roof may be facing the correct direction or allow for the right angle to make use of solar technologies.
This also relates to the size of solar panels, both in terms of capacity and their physical dimensions.
Most residential solar panels are between 300W and 400W.
The capacity of your roof impacts the number of solar panels you can install and therefore how much energy you can generate. This is also because different solar panel sizes have different dimensions.
If you are installing 12 solar panels (350W), they would require a surface area of 24m². It is therefore important to know how much space you have. The table below outlines the average solar panel dimensions and weight per system size.
Solar panel size (W)* | Solar panel dimensions* | Weight per panel |
---|---|---|
350 | 1.6m x 1m | 18kg |
400 | 1.67m x 1m | 18kg |
450 | 1.9m x 1m | 21.6kg |
When deciding how many solar panels you need, it can be difficult to account for all the factors involved. This is why it’s best to consult a reliable installer and have them provide you with an estimate. Finding a reliable installer can take days of difficult research and calling up companies. If that sounds like a hassle, why not try out our handy service?
We can easily provide you with up to 4 free non-binding solar panel quotes and all you have to do is fill out a 30-second form. Click the button below to get started.
It only takes 30 seconds
The average off-grid home will require a 7kW to 10kW solar panel system. Why so much compared to the modest 4kW system required for on-grid homes? Off-grid power has a lot more considerations.
Going off-grid usually requires a high-power system since you will often be compensating not just for electricity but also for gas. Therefore, the calculations are drastically different already. Added to this, you also need to compensate for the seasonal dips in energy generation during the winter.
These systems will cost between £13,000 to £15,000 and require between 38m2 to 54m2 of roof space.
However, the most accurate way to determine the cost of solar panels for your home is to find an installer. It’s important to find a reliable one that can advise you and can execute the installation smoothly. Moreover, you should always get multiple quotes to ensure you are being given a fair price. Yet how time-consuming and daunting can the searches be? Weeks can pass before you find a single quote!
Luckily, GreenMatch can do the legwork for you! Fill in the contact form and get up to 4 tailored quotes from suppliers in your area. The service is free and non-binding!
It only takes 30 seconds
To determine how many solar panels you need for your home, you will need to consider your energy requirements, the size of your roof, and the sun hours in your area. For the most accurate calculations, you need to consult a solar panel installer who can assess your home.
In the UK, you will need between a 7kW to 8kW system. This number is an estimate since there are many factors that can affect how many solar panels you need.
A 3 bedroom house roughly requires a 4kW solar panel system. However, this number is based on average energy consumption, which can vary for different households.
While this can depend on the size of your household, most 3-bedroom homes can be self-sufficient with 4kW systems.
Rawal Ahmed is a writer at GreenMatch with an interest in sustainability and a background in background in tech journalism and digital marketing.