How Many Solar Panels Do I Need To Power A House? (2024)

Last updated: January 21, 2024

How many solar panels do you need to power your house in the UK? In this guide we’ll outline all of the essentials you need to power your home with solar energy.

Energy from sunlight is a renewable and clean form of energy.

Solar technologies use photovoltaic (PV) panels or mirrors to concentrate solar radiation to convert sunlight into electrical energy.

This energy can be converted into electricity or stored in batteries or thermal storage. When the sun shines on a solar panel, the energy is absorbed by the PV cells in the panel.

This energy generates electrical charges that move in reaction to an internal electric field in the cell, resulting in the flow of electricity.

How many solar panels does the average house need (UK)?

There is no straightforward answer to this.

There are three key factors to consider in order to extract the maximum amount of energy and efficiency out of the solar panels.

The key is to determine your roof size, your average daily energy consumption, and the sunlight duration where you will install the solar panels.

The amount of electricity that solar panels can produce is determined by the number of hours of sunlight, which is controlled by your location.

It is always a satisfactory decision to place the solar panels at a place where it gets the most amount of sunlight.

In other words, to determine the number of solar panels required to efficiently provide energy to any space you need to keep a check on the number of sun hours since, in the UK, the sun hours drastically vary.  

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Another deciding factor is the consumption of energy. Take estimation of average consumption in kilowatt-hours (kWh) of the overall energy.

This includes taking all the energy consumption sources into account. To be on the safer side, keep a margin in case you end up consuming more.

The size of the roof also matters because it determines the number of solar panels that can be installed there.

In ideal conditions, the roof should receive as much sunshine as possible while also supporting the weight of solar panels.

How can I calculate the number of solar panels I need?

The most straightforward way is to go through your recent bills and determine the average energy kWh consumption.

To figure out how many solar panels you need by calculating your household’s hourly energy consumption by the peak sunlight hours in your area and dividing the result by the wattage of a panel.

To define a range, consider low-wattage (150 W) and high-wattage (370 W) examples (for example, 17-42 panels to generate 11,000 kWh/year).

It is important to note that the size of your roof and the amount of sunshine it receives also matter.

Another deciding factor is the number of residents in the household.

A 6kW solar panel system is recommended for homes with more than five occupants, whereas a 5kW solar panel system is usual for homes with four occupants.

A 4kW solar system is one of the most popular sizes for domestic solar systems, as it is appropriate for homes with 3 to 4 people.

The quantity of solar panels required in a home depends on whether your installation is 3kW or 6kW, as well as the size of those panels.

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For example, if you want to install a 3kW solar system with 250W panels, you’ll need 12 panels. A 6kW system would necessitate the use of 24 solar panels.

Household SizeAnnual Electricity UsageNumber of Solar PanelsSize of Solar Panel System
1 bedroom1,800 kWh62.1
3 bedrooms2,900 kWh103.5
5 bedrooms4,300 kWh144.9

Types of Solar Panels

Monocrystalline solar modules

These panels accumulate lesser space than polycrystalline panels while providing roughly the same efficiency. They can, however, be more pricy.

Polycrystalline solar modules

The manufacturing procedure for these panels is substantially simpler. This makes them less expensive; nevertheless, they are slightly less efficient at high temperatures, but not by much when used for domestic applications.

They do, however, take up more room because you need more of them.

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Thin film solar cells

These work by layering multiple layers of material onto a substrate foundation and employing substrate and photovoltaic cells.

There are numerous materials that can be used; they are easy to mass produce and can be less expensive and more versatile.

Amorphous silicon solar cells

These often contain numerous layers that are stacked to ensure optimal performance, although they are less efficient when compared to other varieties.

Biohybrid solar cells

These are designed to use a more natural manner of photosynthesis by blending organic and inorganic substances.

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This equates to about 100 per cent efficiency, but they produce less electricity overall.

What type of solar panels should I install?

A number of options are available for solar panels, however, in most cases, monocrystalline or polycrystalline solar panels are used.

Monocrystalline solar panels have the efficiency to convert between 15% and 20% of the sun’s energy into potential power.

This sort of solar panel is also more space efficient than others because it generates more energy per area.

A monocrystalline solar panel generates 10W more than a polycrystalline solar panel of the same size. The cost, however, gets higher because of their high efficiency and silicon purity.

Polycrystalline solar panels generate more electricity over the year than monocrystalline panels due to their greater temperature tolerance.

Polycrystalline panels are less efficient as well as less expensive than monocrystalline panels because their silicon material is less pure.

The average efficiency rate will be between 13 and 17 per cent.

 Hence, you can choose either one depending on your budget and space.

How much do solar panels cost?

On average a 3kW solar panel system costs £5,000-£6,000, can cover the electrical expenditures of a modest house with 1-3 inhabitants.

You can save £160 per year on your electricity cost with this method.

A 6kW solar panel system would be necessary for larger households that house 4 or more people.

This might range from £8,000 to £10,000. Every year, a 6kW system can save you £430 on your electricity expenses.

Do I need battery storage?        

Battery storage eliminates the need to rely on your utility to bring electricity to your home on the majority of days of the year.

And you can always save some battery capacity so that if the power goes out in your neighbourhood, your house will be the only one with lights on.

Keep in mind, though, that battery storage will incur expenses.