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Solar Panel Installation Cost

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Solar panel installation cost

How much does solar cost to install?

You're considering going solar, but now the big question... what is the average solar panel installation cost? As a ballpark figure, a standard 4kWp domestic system costs around £5,500 including VAT. Ballpark figures are good to gauge if solar PV is an option for you, but every system quote you get will be bespoke to your situation, for the many reasons we cover in this guide.

Solar PV installation cost breakdown

Here’s a breakdown for an average 4kWp system with a straightforward install. As we’ll see, these elements can vary depending on many factors, but as a rough guide:

 

Average cost (ex VAT)

Percentage of total cost

Goods

Modules

£1,128

20%

Inverter

£495

9%

Mounting kit

£520

9%

Electrical equipment

£368

7%

Services

Scaffolding

£500

9%

Design & installation

£1,965

35%

Testing & commission

£435

8%

Structural survey

£150

3%

MCS registration

£35

1%

This gives a total system cost of £5,596 ex VAT:

  • kit cost £2,511 ex VAT,
  • services cost £3,085 ex VAT.

This system was quoted using 13 x JA Solar 310W panels, a Solis 4kW inverter and K2 mounting system on a concrete-tiled, single-orientation, rectangular roof layout.

For a personal quote, please do get in touch:

Request free advice / quote

Optional extras

With most systems we offer, or advise, some optional extras such as:

  • Bird protection - mesh around the panels to safeguard against troublesome pigeons nesting underneath. Costs for this start at about £400.
  • SolarEdge upgrade - an inverter with optimisers on each panel to maximise generation in partial shading. This adds around 10-15% to the panel costs.
  • Power diverter - a device like the iBoost or eddi that sends excess solar power to your hot water tank instead of the grid. This costs about £450.
  • Battery storage - a battery system to save up generated solar power throughout the day so you can use it in the evening and overnight, alongside other features like power cut protection and off-peak charging. Batteries add about £8-10k to the system cost.

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How cost varies with system size

Here are some rough prices using similar system specifications to the example above, assuming a straightforward installation on one roof face in a block array:

System size

Number of panels

Average cost (ex VAT)

1kWp

3

£3,900

2kWp

7

£4,400

3kWp

10

£5,100

4kWp

13

£5,700

5kWp

16

£6,500

6kWp

20

£7,900

7kWp

23

£9,100

Since some components of the cost are affected more by system size (e.g. equipment) than others (e.g. scaffolding), the overall quote doesn’t scale linearly:

Average cost by system size

What factors can affect cost?

  • Complex roof and electrics layouts, or multiple aspects, take longer to design and install, which affects this part of the cost.
  • If you’re located towards the edges of our installation area, our prices will also be a little higher to account for travel.
  • The kit costs increase if you decide to go for premium panels and inverters, or choose any optional extras.
  • Scaffolding costs go up the more stories and roof orientations your building has or, we’ve found, if you’re based in London.
  • Roof type affects the ease of install and so the price. Slate and plain tiled roofs are more expensive to install on than traditional tiles. Flat roofs are also more costly because of the different mounting system. 

How costs have changed over time

As technology develops, popularity increases and PV can be manufactured at scale, product costs continue to fall. In the past decade, they’ve dropped over 50%.

Using government data for average install costs across the country, we can see how the price has varied over the last few years:

Average cost of 0-4kWp systems 2013-2019

Data source.

While this price drop will plateau (as the products only make up part of the install cost), it’s an encouraging trend that’s led to solar energy becoming affordable for more and more people.

So is it worth waiting for prices to fall ever further? Probably not. Any equipment cost reduction will likely be outweighed by the savings you could make by going solar now.

Why the cheapest quotes aren’t always best

Solar PV is a significant investment, with many rewards, but you should always trust the company you’re hiring to install. If you get a quote that seems too good to be true, it probably is. Our industry has seen its share of scammers, so make sure to question a cheap quote:

  • Does it include all aspects of the installation (e.g. a structural report, scaffolding, guarantees)?
  • Is the installer MCS certified and registered with the RECC, adhering to the high standards of these schemes?
  • Does the company have good reviews or recommendations?

Other costs to consider

While the vast majority of a solar installation is paid in the upfront cost, there are a couple of other future expenses worth bearing in mind:

  • Inverter replacement. Most inverters last about 12-14 years, so will need replacing during the system’s lifetime of 25+ years. Allow about £1000 for this.
  • Maintenance. The joy of PV systems is how little maintenance they need, and most of the time you can spot any faults by checking your online monitoring for sudden drop offs in generation. We offer electrical inspection and testing services, as well as panel cleaning, which we recommend every few years for flat roofs or polluted areas.

solar panel maintenance checklist

Are solar panels worth the investment?

Financially speaking, solar panels are absolutely worth the investment - often bringing a greater return than you’d get from putting your money in a savings account. You can get a return on investment of over 10%, which is non-taxable for individuals, and passive - it only relies on the sun.

Another way of looking at it is by comparing the lifetime cost per unit of electricity from solar with grid prices. Our latest calculations bring this to 8p/kWh for domestic solar vs a current rate of 16p/kWh for the average import (and rising 7% year-on-year…).

Of course, this is putting aside all the environmental benefits of solar, such as fighting the climate crisis and reducing air pollution.

Solar panel payback

Solar panel payback is usually in the region of 10-15 years, which is pretty good when the system lasts 25+ years. The payback depends heavily on your choice of equipment, electricity usage and tariff. For a personal estimate, try out our solar calculator:

Use solar calculator

How to increase your savings

In the absence of subsidies, the best way to maximise the financial benefits of PV is by using your solar energy on site. The more you can displace usage of grid electricity (the price of which is rising year-on-year), the more you’ll save. But how do you do this?

  • Solar power is obviously generated during daylight hours, so it’s worth shifting energy intensive usage (e.g. dishwashers, tumble dryers) to the daytime. If you’re out at work during the day, you can make use of smart appliances and timers to do so.
  • Excess power can be diverted from the grid (where you’ll only receive a small export payment) to a more useful application like warming your water through an immersion heater or charging up an electric car.
  • Alternatively, you can use battery storage to save up solar electricity during the day and then draw on it once the sun goes down.