Investing in solar panels can be daunting if you’re not familiar with the lingo –
there are a plethora of solar-specific definitions, energy is measured in all
sorts of ways, and don’t get us started on the robotic, consonant-packed panel
names.
If you’re already familiar with all things solar, why not dive in and get yourself
a quote for a new solar panel system?
- A solar panel’s power output is measured in kilowatts (kW)
- A three-bedroom house will typically need a 3.5 kilowatts peak (kWp)
How much energy does a solar panel produce?
Typically, a 3kW or 4kW solar panel system will produce enough energy for a
family-sized home of 3 to 5 people, while a 1kW or 2kW solar panel system
will be about the right size for a couple or single occupant.
The average 3.5kW south-facing domestic solar PV system will produce
about 3,000kWh per year (8.21kWh per day).
Solar panel power output
Let’s start off with the basics – a solar panel’s output is expressed in watts. On average, a domestic solar panel has a power output of around 265 watts, although it can range anywhere from as little as 225 watts to more than 350 watts.
The higher the wattage of a solar panel, the more electricity it can produce under the same conditions – but these conditions will depend on where you live, your roof’s angle, and the compass direction your home faces.
A south-facing house in south England with a 40° roof will be best positioned to generate the most solar energy, with a 300-watt panel on this home producing 363 kWh per year, according to European Commission data and our calculations.
However, a more typical UK home – a west-facing roof in Birmingham that’s pitched at 35° – will produce 225 kWh per year with the same panel.
And a house in North Scotland with the same setup will generate 190 kWh per year, the lowest in the UK.
How much solar energy does your home need?
This all depends on two things: how much electricity you use, and how much of your home you want your solar panels to power.
If your household has a particularly high energy usage, or you want to solely rely on solar panels to power your home, we’d recommend getting solar panels with a high output – around 300 watts (per panel) or more.
However, if you don’t use much electricity day-to-day, or only want solar panels to subsidise some of your home’s energy usage, you can choose solar panels with a lower output – around 225 to 275 watts.
Most homes will install several solar panels, known as a solar panel system. A typical 3-4 bedroom house will require a 3-4kWp solar panel system, typically composed of 12-16 solar panels.
The output of a solar panel system can be calculated by multiplying the wattage of each solar panel by the total number of solar panels. For example,
a home in Reading with four 250-watt solar panels would have a 1 kilowatt (kW) solar system (250 x 4).
Most domestic properties have between a 1kW and 4kW solar panel system, depending on how much power they need and the size of their roof.
