Are Solar Panels Worth It In The UK? Solar PV In UK

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Is solar power worth it in UK?

Are solar panels worth it UK?

Can we believe everything we hear about solar power in UK? Installation companies tell us that you’ll save AND earn money with your domestic solar system, while governments tell us it’s essential to use renewable energy and save the planet.

In this post I walk through the important issues:

  • What are the solar incentives in UK?
  • Do solar panels really save money in the UK? Is it worth it?
  • How to calculate solar system production in your area.
  • Are solar panels really saving the planet?
  • What happens to home value in UK after installing solar panels?

Let’s find out if UK solar panels are worth it or mostly ‘hype’:

As a general rule, solar panels are still worth it in the UK. There are no solar incentives available and savings depend on a home’s level of energy usage, plus geographic location. For example, a 7kW solar panel installation based in Sheffield, UK would taken 21 years to payback the installation costs.

Video – Are Solar Panels Worth It In The UK?


What is grid tied solar system?

A grid-tie solar power system is connected permanently to the power grid, and power flow in or out of the grid is measured by a smart meter.

The diagram below shows a basic diagram of a grid-tie solar system:

Diagram: How a grid-tied solar system is connected.

Connection diagram for grid-tied solar system

Net-metering is the American style, but a UK Smart Meter does exactly the same thing.

You need a correctly sized solar panel installation and careful balancing of energy usage to maximize the benefits. A very cool way of making the system much more efficient is to install solar storage batteries.

These can store energy generated in the middle of the day, when you’re not using it, and save it for the evening or night.  Of course, there’s an extra cost – see later on in the post.

How many kWh does a solar panel produce per day UK?

There are several factors impacting solar power generation and how much any solar panel will produce:

Table: Solar Panel System Losses Explained

Cause of Energy Loss

Percentage Loss

Total Losses



23.8% lost

Dust and Dirt




Spectral Losses




Thermal Losses


Array Mismatch


DC Cable Losses


Inverter Losses


AC Cable Losses


From the table above you can see that about 23% of the power generated is lost in various ways. It’s essential to maximize output by mininizing losses.

Irradiance has the biggest effect of solar panel output, which is the amount of energy from the sun falling on the surface of a solar panel.

This energy varies from place to place. In Death Valley, Nevada, it’s very high. In Glasgow, UK it’s very low. It has a big impact of solar power production and in some cases may prove that it’s just not worth it.

Table: Irradiance comparision, US and UK cities


Chicago, Il

London, UK

Glasgow, UK

Houston, Tx

San Fran., Ca

Irradiance (peak-sun-hours)






Irradiance values are used to calculate solar panel array production and is measured in kWh/m2/day or year. This is used by solar installers to calculate how much power a solar panel can produce in UK and elsewhere.

How to work out irradiance for your location?

You don’t have work it out!

Luckily, there are specialized websites with databases of historical irradiance for every location on the planet, such as

Image: Compare Solar Irradiance Lancaster, Ca, USA and Manchester, UK

Hoe much power can solar panels produce in the UK?

Solar panel power output in UK depends on the irradiance value – USA and UK compared.

Looking at the image above, you can see there is quite a difference between the possible power output from a solar system in California, USA  and in and Manchester, UK:

  • Irradiance in Lancaster, Ca is 8.084 peak-sun-hours (kWh/m2) per day
  • Irradiance in Manchester, UK is 1.960 peak-sun-hours per day

A 100 watt solar panel in Manchester, UK would generate 1.96 x 100 or 196 watt-hours per day. (Equivalent to 71.5kWh/year.)

A 100 watt solar panel in Lancaster, Ca, USA would generate 8.084 x 100 or 808 watt-hours per day. (Equivalent to almost 295kWh/year.)

How much does a 10kw solar system produce UK?

A solar system generation calculation uses a combination of peak-sun-hours for your location and the losses you can expect from the average solar power system – see image below:

Infographic: The 10 Major Losses Of A solar Power Installation

Energy losses for UK home solar panels sizing

Infographic showing percentage losses for home solar panel sizing

Basically, about 23% of all electricity generated is lost, which equals 230 watts for every 1000 watts!

Before we look at the losses, let’s see what a 10kW solar system should generate in theory:

        • Location: Sheffield, UK
        • Irradiance in Sheffield, UK: 2.118 kWh/m2/day (or peak-sun-hours)
        • Energy generated per day = 10000 watts x 2.118 = 21.180kWh/day
        • Energy generated per year = 7731kWh/year

The losses are about 23%, so we need to deduct that:

        • Solar losses = 7731kWh x 23/100 = 1778kWh
        • Real solar production of 10kW solar array = 7731 – 1778 = 5993kWh/year

Do you really save money with solar panels in UK?

This question can get complex, particularly if you factor in solar batteries for energy storage. With a normal grid-tie solar system and no batteries, you need to balance power generation against the annual cost of you electricity.

The average cost of UK electricity is around 14.4 pence per kWh, with a standing charge of 20.58 pence per day. We can ignore the standing charge, as it will always be there in a grid-tied solar power system.

The average energy used in a UK household is approximately £560 per year, so we can use this as our benchmark for solar calculations – how many solar panels would you need to generate the same power?

          • £560/14.4 = 3889kWh/year


How many solar panels do I need to power my house UK?

Solar installers usually multiply the theoretical solar power output from a solar installation by 1.44, so that all the possible losses are taken into account.

    • In this case, the energy we need to generate = 3889 x 1.44 = 5600kWh/year

We’ll stick with Sheffield, UK irradiation values for our calculation:

          • 5600kWh/365/2.118 = 7244 watts of solar panels
          • Number of 250W solar panels = 7244/250 = 29 panels

Solar Calculator UK

  1. Use the calculator below to work out how many panels you would need in your location. Find the previous year’s energy bill from your electricity bill, either paper or online.
  2. Go to GlobalSolarAtlas , enter your location and read off the irradiance value (see image below).


Use UK irradiance to size domestic solar panels

Historical irradiance data used for UK solar panel sizing



How long does it take for solar panels to pay for themselves UK?

Solar installation cost for UK is estimated at £1.56 per watt. (From GOV Data.)

For the previous example using Sheffield, UK as the location and an average annual energy usage of 3889kWh, the 7244W of solar installation would cost:

          • 7244 watts x 1.56 = £11730 

Now divide the installation cost by the cost of electricity per year to find how long the payback period is:

          • £11730/£560 = 20.94 years

Do solar panels Increase Home value UK?

This is a confusing issue in the UK. It’s more clear in the USA, where a homeowner can expect something like a 4% increase in their home value after installing solar. maintain that the average value increase on a solar home in UK is about £30k, while Which reports from estate agents that it’s a wash i.e. solar panel installations have no impact on house sales.

My own feeling is that it depends on the area, social segment and house price. Most of all, it will probably depend on other factors:

        • the buyer is an eco-warrior, determined to do his best for the planet
        • a financial-savvy buyer knows the long-term benefits are impressive
        • what style are the solar panels? Flat, contoured or tiles?
        • does the system have solar storage batteries?
        • is the solar system able to generate all the household’s needs?

What are the best solar panels UK?

For the best selling solar panels, there’re all about the same quality – choose from this list and you won’t go wrong:

        1. LG Solar Panels, UK
        2. Canadian Solar Panels, UK
        3. SunPower Solar Panels, UK
        4. Suntech Solar Panels, UK
        5. Panasonic Solar Panels, UK
        6. Sharp Solar Panels, UK
        7. Trina Solar Solar Panels, UK
        8. JA Solar Panels, UK
        9. Yingli Solar Panels, UK

Can I get solar panels for free UK?

Unfortunately, this option doesn’t exist in UK anymore.

There is a possibility for the DIY enthusiast though. Big solar farms carry out regular checks on their solar panels arrays, removing ones that don’t perform.

Scrapping solar panels is quite an expensive business and recycling them even more so. If you phone a solar farm in your area and just ask, you might get some for free!

Solar farms use big panels and even if  only 60 or 70% efficient because of deterioration, they will still generate plenty of power for your DIY projects, or even a whole house!

Can I install my own solar panels UK?

Yes, a solar panel installation is easily within the scope of a competent DIY enthusiast. There are plenty of solar kits with full instructions online.

The only caveat is that such a self-installed solar system must be commissioned and energized by a registered installer.

How much do solar panels cost UK 2021?

Latest government figures indicate that a domestic solar installation costs in the region of £1560 per kW installed.

Individual solar panel costs can vary greatly – always buy the best you can afford.

Are solar panels worth it UK 2021?

For sure, the benefits are reducing every year as governments and other bodies remove the solar incentives that subsidized solar installations.

My own feeling is that it’s still marginally worthwhile, depending on your energy consumption and size of system installed.

How many solar panels do I need to power my house UK?

For an average energy usage of 4000kWh/year, 29 solar panels each 250 watt rated would be need to meet total energy needs.

Are solar panels worth it in Scotland?

Even 10 years ago I would have said ‘no’, but prices of installed solar are reducing every year, changing the game.

For sure, the irradiance in Scotland is very low compared to most other parts of the UK, so the payback period will also be longer. That said, it’s a long-term energy strategy and it’s to be expected.

Why is my electric bill so high with solar panels?

Possible reasons are:

      1. The system was incorrectly sized in the first place.
      2. You are using more electricicity.
      3. The sun’s energy has been low, so power output is low.
      4. Perhaps the system isn’t working properly – get it checked by the installer.

What are the 2 main disadvantages to solar energy?

      1. Solar panels can’t generate power at night and can’t store it.
      2. Solar panels are diffciult to recycle, so get dumped – toxic waste problem.

Why solar panels are bad for the environment?

Solar panels can spread toxic substances such as corrosive chemicals and heavy metals into the environment.

This happens twice – when they are being manufactured and when they being scrapped. Recycling is possible, but is expensive.

The cheapest solution is also the worst, which is to dump them in landfill, a surefire way to leech out toxic elements into the soil.

How long do solar panels last?

Most manufacturers provide solar panel warranties of between 20 and 25 years, but they actually last much longer.

You can expect solar panel putput to be about 90% of new after 25 years, reducing at about 0.8% each year of use. However, a solar panel can produce power for up to 60 years!

How many solar panels would it take to power a house off grid?

As a basic rule, about the same as for a grid-tie system, plus 25% for battery-charging and to account for times when the weather isn’t so great. This post explains everything.

A big part of the cost of an off-grid system, up to 30%, is for the batteries. The size of your solar storage will depend on the number of hours autonomy you need, i.e. how many hours do you want to be able to run the house without any solar input?

How many watts do I need to go off grid?

First of all, it depends on how much energy you use each day. Let’s say it’s 15kWh per day (UK average) and you live in Sheffield, UK which has an irradiance of 2.118 peak-sun-hours.

          • 15000/2.118 = 7080 solar watts

However, solar systems lose about 23% fo the power generated while in normal operation, so we need to multiply the solar watts by 1.44 to account for this:

          • 7080 x 1.44 = 10195 solar watts to go off grid

Does switching to solar mean you go off the electrical grid all together?

Normally, no. A grid-tie system remains connected to the grid but doesn’t always pull power from the grid. It depends on how much the house is taking and how much the solar system is generating.

Do solar panels work if the power goes out?

Solar panels are disconnected from the grid if the power goes out. This is a safety feature called ‘anti-islanding’ and it’s done automatically to protect any workers that may be working on the utility grid repairing the power lines.

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