How Many Solar Panels Do I Need?
If you're looking into a greener, cheaper, and more sustainable domestic energy source, you're likely wondering "How many solar panels do I need to run a house?". The answer depends on your annual energy use, the solar panel sizes, the availability of space in your home, sun hours in your region, and each panel's power output. Each of these factors has considerations, so let's dig deeper into what you need to know to get started.
Please note: the article is geared primarily towards the UK market, so all numbers and prices are relevant to that particular region. Your country may have different standards and regulations. Additionally, you can learn about installation costs here as this article does not include them.
However, if you do live in the UK and are looking for reputable MCS accredited engineers who can offer you the best prices for solar panel installation, our service is a great way to find the best deals. We can help you avoid the headache of finding an engineer you can trust and give you access to all the savings you're missing out on with your current energy setup. Press the button below and easily procure up to 4 free, non-binding quotes from experts in your area.
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How many solar panels to power a house in the UK?
To calculate how many solar panels you need, you will have to calculate the power you need for your house with regard to your annual electricity usage (check your electricity bills to learn about this). Residential solar panels typically range from 250W to 400W. Depending on your home's average energy consumption, you may want to consider higher-output solar panels. The average energy usage in the UK is 2,900 kWh. For solar panels of a larger size (400W), the output per panel is illustrated in the table below:
| Size of Solar PV System | Number of 400 Watt Solar Panels | Estimated Annual Output |
|---|---|---|
| 1.2 kW | 3 | 1,200kWh |
| 2 kW | 5 | 2,000kWh |
| 3.2 kW | 8 | 3,200kWh |
| 4 kW | 10 | 4,000kWh |
It's possible that these panels may not fit your needs or are too expensive. In such cases, you can spring for 250W panels. The output per panel for these systems breaks down as follows:
| Size of Solar PV System | Number of 250 Watt Solar Panels | Estimated Annual Output |
|---|---|---|
| 1 kW | 4 | 1,000kWh |
| 2 kW | 8 | 2,000kWh |
| 3 kW | 12 | 3,000kWh |
| 4 kW | 16 | 4,000kWh |
For reference, generating 500kWh (kilowatt hours) per month requires 46 panels with 100W capacity, or (alternatively) 16 PV panels at 300W each, or 12 PV panels at 400W capacity. A 5-bedroom house ordinarily needs 3,500 to 3,700kWh, therefore it will need 10 to 12 panels of 400W capacity. It's also useful to understand how many sunlight hours you get to make the best use of your setup.
How do I determine how many solar panels my house needs?
One of the major considerations is always going to be how many panels you can afford along with your energy needs and available roof space. The higher your energy needs, the larger the size of the solar panel system you will require. Here is a table that can help you break down the potential costs of various systems.
| kW of Solar Panel System | Potential Cost (before installation) |
|---|---|
| 1.2 kW | £1,500 – £3,000 |
| 2 kW | £3,300 – £3,800 |
| 3.2 kW | £4,000 – £5,400 |
| 4 kW | £5,000 – £6,000 |
| 5kW | £6,000 – £7,000 |
A 1kW system costs £1,800 minimum, while 2kW systems can cost roughly twice as much and 3kW costs thrice as much, as one would expect. However, the 4kW systems provide you with a decent discount on the panels for the 4th kW (a few hundred pounds, depending on the base price). These prices can fluctuate for different areas of the country.
If you're in the market for a solar panel system, you can check out our service to find a trusted engineer in your area. Avoid the headache of searching for an installer you can trust yourself and let us find the best offers from professionals in your area. You can obtain multiple free, non-binding quotes from certified engineers in your area simply by pressing the button below.
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How do I calculate my own energy needs?
In the UK, the average annual electricity usage stands at around 3,800 kWh but this will go up or down depending on the size of your home, the number of people in the property, and your energy habits. Check your energy bills to see how much you spend annually.
Detached homes tend to have the highest demand for energy while a mid-terrace home is likely to have lower demand. To determine how many solar panels you might need, you need to look through your electricity bills to learn your annual usage. Once you know that, the table in the next section can help you decide which solar panel sizes and wattage are most appropriate.
Here's a handy table that illustrates how different types of homes have different energy needs.
| House Type | Average Annual Energy Usage (kWh) | Number of 320W Solar Panels | Total Output of Solar PV System (kW) |
|---|---|---|---|
| Detached | 4,153 | 13 | 4,160 |
| Bungalow | 3,866 | 12 | 3,840 |
| Semi-detached | 3,847 | 12 | 3,840 |
| End Terrace | 3,442 | 11 | 3,520 |
| Mid-terrace | 2,779 | 9 | 2,880 |
| Flat | 2,829 | 9 | 2,880 |
Keep in mind that the table estimates consumption based on averages and makes assumptions about the number of inhabitants based on how many bedrooms there are (a detached home with a single inhabitant but more rooms will have far lower consumption than the rate above, for example). These numbers can vary from household to household, so you may need to do an individual analysis for your own home.
There are other factors that can complicate your installation, particularly if you live in a flat or apartment. This may require clearance with your neighbours and/or landlord, reviewing building codes in your area, etc.
However, if you're looking for a hassle-free installation, you can use our service to find the best MCS certified engineers in your area and start saving on your energy bills. Solar panels are a great way to mitigate soaring energy prices. Click the button below to get 4 free, non-binding quotes at competitive rates.
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Sizes of solar panels: solar panel dimensions in the UK
Another important factor to consider is the size of your roof or the area of the property where you want to install your panels. The average solar panel system produces 1.8kWh to 2kWh per day and requires a minimum of 13m2 of roof space. A 4kW system with 16 panels can range from 21m2 all the way up to 28m2, depending on the capacity per panel. This size difference can vary based on whether the individual solar panels are smaller 250W ones or 400W.
How many solar panels can I fit on my roof?
The amount of solar panels you can fit on your roof varies depending on the free space you have. Here's a handy table to help you figure out how many panels you can install (the table uses averages, but sizes can vary heavily based on the types of panels and their arrangement). The table below can help you calculate how many solar panels you need.
Additionally, while most homes in the UK meet the requirements for solar panels, there are still certain criteria you need to meet to maximise solar panel efficiency:
- A south-facing roof will deliver optimal results, while East-to-West facing ones can lose about 15% energy efficiency.
- The level of shading in your surroundings.
- Roof pitch of 30-40 degrees.
- Whether there’s enough space (a 4 kW system can take up around 28m² of space).
- Energy Usage Times
How many solar panels does your home need? A conclusion
Taking all the factors stated earlier into account, here are the typical solar panel arrangements for the average flat or house in each category, assuming they meet the average size and consumption for British households and are based in an optimal location for solar panels.
| Household size | Solar PV System | Roof Space | Annual Energy Output | Number of 400W Panels |
|---|---|---|---|---|
| One-bedroom flat | 1 kWp | 6m² | 790kWh | 3 |
| 1-2 bedroom house | 2 kWp | 12m² | 1,590kWh | 5 |
| 3 bedroom house | 3.5 kWp | 20 m² | 2,645 kWh | 8 |
| 4-5 bedroom house | 5 kWp | 28 m² | 3,700 kWh | 10 to 12 |
Prices are, approximately, as follows (depending on your region and the particulars of your residence):
- 1 kW = £1,800 – £2,000
- 2 kW = £3,300 – £3,800
- 3 kW = £4,800 – £5,300
- 4 kW = £6,000 – £6,500
- 5 kW = £7,700 – £8,200
Factors to keep in mind that might affect the efficiency of your setup include sunlight hours, the slope of your roof, how much shade there is around your house, and which direction your house faces in relation to the sun. Keep these variables in mind because they may affect how many solar panels you need to power your house.
While prices may make you hesitant, it's important to remember that solar panels not only help the environment and allow you to save money in the long run but also enable you to give excess energy back to the grid in exchange for money. Bear in mind, these are only one of the many benefits of solar panels.
Find solar panel installers
Hopefully, all this information has been useful in learning more about solar panels and how many you need for a home of your size. If you're in the market for solar panel installation, you can learn more about choosing a solar panel installer.
Alternatively, if you're looking for great options and prices, you can use our handy service to get the best deals available from professional MCS certified engineers in your area. Let the experts take it from here and you can start saving on your energy usage. We understand that installing solar panels can be complex for many people, which is why our service takes all the pain out of finding the right person for the job and helps you find an offer that suits your home and needs precisely. You can obtain up to 4 free, non-binding quotes simply by clicking the link below.
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FAQ
What should a 4kW solar system generate per day in the UK?
4kW systems generate 16kWh per day. However, this can depend on a series of extraneous factors related to the house and energy consumption.
How many solar panels are needed to run a house off-grid?
This will depend on how much you plan to consume, the size of your house, and factors related to your house/its placement.
How many solar panels do I need for 500 kWh per month?
Generating 500kWh can be done with a number of panel arrangements. With 100-watt panels, it takes 46, while a 300-watt requires 16 PV panels, and 400-watt systems need 12 PV panels. This can, however, depend on various factors that increase or decrease panel efficiency.
How many solar panels do I need for a 4-bedroom house?
A 4-bedroom house ordinarily requires 4 to 5kW solar panel systems. However, the precise type of system can vary based on several factors.
How many solar panels do I need for 2,000kWh per month?
Assuming sunshine hours of 3.5 to 4 per day, 35 to 40 400W solar panels would be enough to generate 2000kWh per month. The level of power a solar panel can generate depends on several factors, making it difficult to determine precisely.
How many solar panels does the average UK home need?
The average energy usage in the UK is 3,800kWh, requiring a 10,400W system. However, this can vary depending on the size of your household, energy consumption, and a few other factors.
What is the standard solar panel size?
The average solar panel system requires a minimum of 13m2 of roof space. A 4kW system with 16 panels can range from 21m2 all the way up to 28m2 (the difference can vary based on whether the individual solar panels are smaller 250W ones or 400W). The cost and power per panel can vary depending on sizes.
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