20kW Solar System UK: Price, How Much Does It Produce, How Big, and More

How Much Will a 20 kW Solar System Save?

An 20 kw solar system for the right home or business should save around £109100 over the course of its expected 25 year lifetime. That’s based on grid electric costing £0.34/ kWh (last updated October 2022). That’s roughly £4365 per year in savings, without taking into account inflation or rising electric prices (which both add to your savings if you invest in solar soon).

Rising Electric Costs

The cost of electricity in the UK has consistently ‘outperformed’ inflation. You can see the last few seasons of price rises in this chart of Ofgem’s price cap rises:

The amount that electricity costs continue to rise will have a large impact on whether you decide if solar is worth it for you in the UK.

This chart from Ofgem shows a breakdown of the costs that make up the default tariff price cap for a dual-fuel, standard credit customer with typical consumption.

Smart Export Guarantee

The Smart Export Guarantee replaces the older Feed in Tariff scheme. It allows you to get paid for excess energy that your 20 kw solar system produces but you don’t directly use yourself, for example if you’re out during the day when it’s sunny.

Currently you can expect to get up to 15p per kWh of electricity you ‘export’, so for a 20 Kw solar system, with typical usage patterns, you could expect to receive around £1529 per year in payments under this scheme. This rate is available at the time of writing from Octopus Energy.

Electricity Savings

One of the main reasons to consider getting an 20 kW solar system is to save money by directly using the electricity it produces during the day, instead of paying the utility company. The more of your own ‘self generated’ electricity you use instead of buying it or paying for petrol if you’re also buying an electric car, the higher your savings.

With a properly sized 20 kW solar system, you can expect to save around £2836 per year by using your own solar energy.

20 kW Solar Panel System Price

An 20 kW solar system (without a battery) typically costs around £25000 in the UK. That’s including installation and VAT.

You can get a free quote from Honest Quotes to get an exact price. They offer a Zero Upfront Cost option for those that qualify.

How Many Solar Panels for 20 kW System?

Modern solar panels are rated for between 300 – 500w each, or 0.3kw – 0.5kw. That means that you would need between 40 and 74 individual panels for a 20 kW system.

How Big is a 20 kW Solar Array

Each solar panel is around 1.6 ㎡, so in total a 20 kW solar system would need between 65 ㎡ and 121 ㎡ of space, depending on if you go for the more efficient (but also more expensive) panels, or the less efficient ones.

How Much Does a 20 kW Solar System Produce? (In the UK)

On average over a whole year a 20 kW solar system produces 18537.09 kWh in the South of the UK.

There’s several factors that influence how many kWh a 20 kW solar PV system produces. Those are:

  • Shading
  • Location in the UK
  • Roof direction and tilt
  • Time of year
  • Efficiency of components in your system

20 kW Off Grid Solar System UK

Off grid solar panel kit UK

If you’re considering building an off grid DIY solar system in the UK, then you’ll want to calculate how large of a battery you need.

You can then buy the 40 to 74 panels you need.

How Much Does a 20 kW Solar System Produce in Other Countries?

Is a 20 kW Solar System Right For You?

To find out if it’s worth it for you, use our free solar panel cost calculator.

P.S You can also see the specs for 19kW solar systems or 21kW solar systems in the UK. And if you’re thinking of building a DIY Off Grid system, you may find our Off Grid Solar Calculator is helpful.