How Many Solar Panels Do I Need For My Home?

It’s no secret that solar panels can save you money and massively reduce your carbon footprint.

But it’s vitally important to know how many solar panels you need to install for your system to be its most optimal – too few and you lose out on the energy savings, too many and you could be wasting your investment.

This guide explores how many solar panels you need for your home and the three factors that cannot be ignored when installing a solar PV system.

How many solar panels do I need?

It’s worth noting that annual electricity usage is measured in kilowatt hours (kWh) and a 1,000 watt appliance (1 kW) needs 1 kWh of electricity to run.

A solar PV system’s size is measured in kWp (kilowatt peak), which is the amount of energy the system can generate at peak performance. For example, a 5 kWp system will produce 5 kW of electrical power in bright sunshine.

There is no straight answer on how many panels you need as the average number of solar panels in a UK home varies depending on how many people live inside each property.

Properties with five or more bedrooms typically opt for a 6 kWp solar panel system, while those with four residents have 5 kWp or 4 kWp systems. Those with a three-bedroom property also usually have a 4 kWp system.

Any property without a solar battery will only use around half of the electricity produced by the solar PV system – but more on that later.

How to work out how many solar panels I need

There are three important things to consider when working out how many solar panels you need:

1) Your property’s average daily energy consumption

2) The sun hours in your area

3) Your roof’s size and orientation

Let’s take a look at each step:

1) Energy consumption

To work out how many solar panels you need, your property’s annual electricity usage must be calculated. Energy bills are a great indicator of how much energy your property consumes per day.

For example, if your property used 155 kWh in March, then your daily energy consumption is 5 kWH. This also indicates the size of the solar PV system you need.

A general guide for a solar PV system made of 250 W panels is:

  • 1 kWp system: 3 panel
  • 2 kWp system: 6 panels
  • 3 kWp system: 12 panels
  • 4 kWp system: 16 panels
  • 5 kWp system: 20 panels
  • 6 kWp system: 24 panels

For context, the average UK home uses 3,731 kWh a year, meaning that at least a 3kWp system will be needed (and thus 12 panels).

2) Sun hours

There are some people that wonder how effective solar panels are in the UK, mainly due to the relative lack of sun, but it may surprise you to learn that solar panels can be very effective in Britain.

Certainly, some areas of the UK have more sun hours on average than others (England has 4.1 while Northern Ireland has 3.2 for example), but this amount of sun is still sufficient to power a typical solar panel system.

The position of your roof also has a great effect on your solar system’s effectiveness, with south-facing roofs being the most optimal. This is because the sun’s angle is more direct and sunlight will be able to reach the solar panels for longer throughout the day.

Working out your roof’s position and the average sun hours it receives will massively affect how many solar panels you need.

3) Roof size

Talking about rooves, it’s vital to know your roof size so you can calculate if your roof is big enough to fit the solar panels you need.

As a general rule of thumb, the average solar panel is about 1.6 square metres and the average solar panel system requires 10 to 12 panels.

If your roof is too small, don’t worry – you could use fewer solar panels with a higher power rating to compensate.

While you may be able to work out how many you think you need, we always recommend getting a final estimate from a trained professional.

Can I power my home with only solar power?

It is possible to power your home with only solar power and be totally energy independent, but you must have a solar battery installed.

As mentioned earlier, without a solar battery a large percentage of unused energy will be sent back to the National Grid, rather than being used in your own home.

A solar battery works by storing the excess energy produced by your solar panels, which can then be used when the sun isn’t shining – meaning your home could run on 100% solar power and save up to £520 a year.

Even if you’re not looking to be totally energy-independent, properties with a solar battery use more than double the amount of energy than those without one.

What is the best angle for solar panels?

We’ve already established that a south-facing roof is the best position for solar panels in the UK, but what angle must they be in to be at their most effective?

The best angle for solar panels depends on which part of the UK you live in.

In the South and East, a tilt angle of around 30° is ideal, while those living in Northern parts of the UK should aim closer to 40°. This allows for maximum sunlight exposure throughout the day.

It’s also important to note that solar panels should not be in shade for an extended period of time during the day. Any trees or buildings nearby your property can cause this and should be taken into account when installing your solar panels.

Upgrade for free with So Eco

Thank you for reading our guide to how many solar panels you need for your property. Hopefully, with this guide, you can start planning your solar project with confidence.

If you’re ready to go ahead and install a solar PV system, why not upgrade with So Eco?

Did you know that through the ECO4 Scheme, you could upgrade your property’s energy efficiency for a reduced cost? Or even better, for free!

At So Eco, we’re official Energy Company Obligation scheme providers. We can help you upgrade your property for free and save hundreds of pounds a year on your energy bills with the ECO4 Scheme.

For more information, complete our free online eligibility checker and see how we can help you upgrade your property and save money on your utility bills!

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