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Last updated: 27 March 2024

How Many Solar Panels Do I Need in the UK? | 2024 Guide

how many solar panels
  • On average, a 1-2 bedroom house requires 4-8 panels (2-3kW), a 2-3 bedroom house needs between 8 and 13 panels (4-5kW) and a 4-5 bedroom household in the UK will need 13 to 16 solar panels at 6kW each.
  • Your electricity consumption, the direction of your roof, sunlight hours, and the roof space all determine the size of the system you need.
  • 3 bedroom houses are the most common UK household size and will need 10 to 13 panels (350W) which will cost £9,000 to £12,000 on average.

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.

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How many solar panels do I need?

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.

How many solar panels you will need on average

You can consult the table below for an idea of the number of solar panels required to power homes of different sizes.

Number of solar panels needed based on annual consumption
House sizeAnnual energy consumptionNumber of solar panels (350W)Number of solar panels (450W)
1-2 bedroom1,800kWh65
2-3 bedrooms2,700kWh97
4-5 bedrooms4,100kWh1310
*These numbers are rough estimates. Your home’s energy needs may vary.

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.

number of panels

How to calculate how many solar panels you need?

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.

How many solar panels formula

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.

What size solar system do I need?
Size of solar systemNumber of 350W panelsEstimated surface area
*This table assumes 350W Solar Panel dimensions: 2m² per panel

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 system costs + break-even points
Solar panel sizeNumber of 350W PanelsPriceBreak-even point (years)
3kW8£7,000 – £8,00014
4kW10£9,000 – £10,00012
5kW13£11,000 – £12,00015
6kW16£12,000 – £13,00011
*These prices are estimates based on a system using 350W panels. Break-even points calculations are based on Ofgems Typical Domestic Consumption Values. These figures are intended as guidance and not as an exact price. We always recommend getting a tailored quote for your property.

Other factors that may affect the cost of solar panels include:

  • The cost of solar panels in your area
  • Brand or supplier costs
  • Labour costs in your area
  • Site complexities that may require more labour hours

What factors influence the number of solar panels a home needs?

To determine the size of the panels that you need for your house, you need to know the following:

  1. How many sun hours does your home receive?
  2. The direction your roof faces (south-facing roofs perform better).
  3. The capacity of your roof: how much space in square meters is available?
  4. Dimensions of solar panels per size or brand.

Sun hours

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.

Roof orientation and direction

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.

Roof space & capacity

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.

Size of solar panels

Most residential solar panels are between 300W and 400W.

how many solar panels do I need calculation

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.

Required Solar Panel Surface Area
Solar panel size (W)*Solar panel dimensions*Weight per panel
3501.6m x 1m18kg
4001.67m x 1m18kg
4501.9m x 1m21.6kg
*It is important to note that different brands may have different solar panel dimensions.

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.

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How many solar panels do you need for running a house off-grid?

How many solar panels do I need for an off-grid house

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!

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  • Save up to £729 per year

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Rawal Ahmed
Written by Rawal Ahmed , Writer

Rawal Ahmed is a writer at GreenMatch with an interest in sustainability and a background in background in tech journalism and digital marketing.

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