Solar panels: The complete guide (2023 prices) (2023)

Solar panels convert energy from sunlight into electricity that can be used to power your home. (Adobe)

A solar panel is a collection of solar cells that can be used to generate electricity. They collect energy from the sun and then convert it into electricity. This solar energy can then be used to power homes.

Before considering the steps below to work out if solar panels are suitable for your home, it’s worth knowing the average cost of a system – we’ll go into detail about solar panel costs later, but here are some headline figures to keep in mind:

The average UK home with an average-sized family, and an average energy usage:

• Three-bedroom semi with 29㎡ roof space
• 3,000kW annual electricity usage

Would typically require:

• A 4kW solar system
• Cost: £5,942

• Reduce your energy bills: Homes with solar panels in the UK can reduce their energy bills by £610 or more per year depending on the system size and how much energy they use
• Sell solar back to the National Grid: Homeowners can sell surplus energy back to the grid through a Smart Export Guarantee (SEG) tariff
• Increase the value of your home: Potential buyers are willing to pay an average of £2,038 more for a home with renewable energy systems, such as solar panels
• Constant supply of electricity: The average panel can last up to 25 years or more and generate clean energy all year round. In the event of a power cut, if you’ve installed a solar battery, you’ll still have an electricity supply
• Reduce your carbon footprint: Solar panels reduce the amount of carbon dioxide (CO2) emissions that each house produces. The research found photovoltaic panels (PV) produce between 25g and 32g of CO2 per kWh of electricity, compared to 400g/kWh for power generated by fossil fuels

Solar panels are an investment for your home and one that doesn’t pay out in just a few short years. Still, there’s plenty to gain from generating your own electricity, and in the long run, they will pay for themselves and could earn you money.

How much money you’ll save on your electricity bill will vary based on:

• The size of your roof
• Your home’s location in the UK
• The number of panels and power output you need to meet your household’s energy requirements

In the below table, our researchers have calculated the potential costs and savings for a three-bedroom semi-detached house with a Midlands postcode. These figures should give you an idea of what an average UK household stands to gain from installing solar panels.

If your house is located further south, you can expect savings to be slightly higher; for households further north, savings will be slightly lower. The system costs are unlikely to be affected by region, although installation costs may vary depending on the availability of labour and materials.

One of the main reasons for which many homeowners consider installing solar panels is to save money on their energy bills – and this has only increased with soaring energy costs throughout the past year.

Exactly how much you can save on your electricity bills will vary between homeowners depending on how large of a system you install and your household’s energy consumption.

Throughout our research, we discovered that you could save over £400 annually on your energy bills by installing a 6kw to 8kW system and opt in to SEG payments.

The below tables are examples of what you could save on your energy bills based on a 3.5kW system. These figures are from Energy Saving Trust and based on electricity prices as of October 2022.

South East London

Is now a good time to invest in solar panels? – David Hilton, Energy and Renewables Expert

Now is the very best time to invest in solar panels. Energy costs are only rising, and if we can generate our own energy, it’s an ideal outcome. In the past we relied on incentives to help pay for our solar installations. The Feed-in Tariff (FiT) was very generous – around 45p per kilowatt hour (kWh) generated when electricity only cost 9p per kWh – but the installations were also very expensive. The payback time was around 11 years.

When the FiT ended, the solar panel market dropped off a cliff and other renewables came on to the radar for homeowners. But then in 2022, electricity and energy prices rocketed and the appeal of solar PV panels returned. The cost of electricity is now the driver of the payback, and given the cost of an installation is a lot less than it was 10 years ago, the payback period is now around 10 years – sometimes less. This does, however, depend on how much you spend on the installation and how much of the generated electricity you use.

Although we have discussed the potential savings from solar panels, the initial investment is costly, and one that many homeowners should consider carefully. The savings on your energy bills may happen relatively quickly, but the time it takes for you to break even on the initial cost is not.

Solar panels are not an investment that you can expect to see a return on in just a few short years. However, as well as saving money on your energy bills, there’s also the potential to earn money by selling any unused solar energy back to the National Grid. By selling power back to the grid, solar panels may pay for themselves slightly quicker..

There are a few factors that will affect how quickly your solar panels pay for themselves; these include:

• The amount of sunshine you get in your area
• The size and position of your roof and the number of panels installed
• The price of electricity and the SEG tariff – the amount of money you will be paid for the electricity you sell back to the National Grid
• The amount of electricity your solar system generates

The below table will give you an idea of how long it might take to break even on your investment based on all of these factors.

With the continuing soaring energy prices, this has had an effect on the time it takes for solar panels to pay for themselves. Higher energy prices mean that your system will pay for itself much more quickly.

Previously, it took around 14 years for solar panels to pay for themselves. However, as energy prices continue to rise, the break-even point is getting shorter and shorter, with some systems even paying for themselves in less than 10 years.

As well as saving money on your energy bills and earning money back through SEG payments, installing solar panels could increase the value of your home if you decide to sell it. Recent research conducted by FirstPort found potential buyers are seeking eco-friendly features and are willing to pay, on average, £2,038 more for a home with solar panels already installed.

This also means, should you decide to sell your home, you could recuperate nearly half of your initial investment.

There are two types of solar panels:

• Photovoltaic panels: Produce electricity
• Solar thermal panels: Used for heating

Solar panels, also known as photovoltaic panels (PV), capture the sun’s energy and convert it into usable electricity to power your home – this process is called the photovoltaic effect.

Solar PV panels are made up of multiple cells containing conductive materials – most commonly silicon – and when sunlight shines on this material, electrons are released, creating a flow of energy.This energy is captured and converted, and the current is combined with the cell’s wattage to determine how much electricity is created.

A grid-connected solar panel system is connected to the National Grid, which means you’ll never be without electricity. If your panels generate less electricity than your home requires, you’ll have instant access to power from the grid. Should your system generate more electricity than your home needs, this can be exported back to the grid for a profit.

Stand-alone PV panels are not connected to the National Grid. These types of systems are mostly used in remote locations where connection to the grid is not possible. During daylight hours, panels will generate electricity that can be used to power your home, and any excess electricity is stored in solar batteries for use when your panels are not generating any electricity – mostly at night. Stand-alone systems are more costly than grid-connected systems, primarily due to the cost of solar batteries.

Simply put, solar battery systems are designed to store excess energy from your solar panels. This excess energy can then be used to power your home at times of the day when your panels are not generating any electricity.

Solar batteries, in theory, sound like a favourable idea – but one that will cost you around £4,000 on top of your initial solar panel system investment. However, installing a battery will mean you may no longer need to rely on grid electricity and any power cuts in your area will no longer affect you.

As we discussed in the section above, solar panels are usually made up of solar cells, which come in a variety of different materials, each with their own benefits and downsides. The most common panels used for residential solar systems are monocrystalline, polycrystalline and thin-film (sometimes called amorphous).

Monocrystalline cells

Offering the highest efficiency rates on the market, monocrystalline solar panels are so named because they are made of a single piece of silicon. These cells are more popular with consumers who are concerned with the appearance of their panels, as their simple construction offers a sleek, nearly all-black design.

Monocrystalline cells tend to be more efficient and perform better in low-light conditions because the single-crystal construction allows electrons to flow more freely. Thanks to efficiency rates of around 15 to 20 per cent, you would need fewer panels to meet your energy needs than you would with polycrystalline panels. In addition, their efficiency degrades less in high heat than polycrystalline cells and have a longer lifespan than other types of cells.

However, monocrystalline panels tend to be the most expensive type, and the manufacturing process produces more waste, as some silicon is cut off when making the cells.

Polycrystalline cells

As the name suggests, the main difference between polycrystalline and monocrystalline cells is that the former is made of multiple silicon crystals as opposed to just one. The crystals are melted into squares, which are then connected to form a solar panel.

The downside of using multiple crystals is reduced efficiency of around 13 per cent, as there is less room for electrons to move around. This also means you would need more polycrystalline solar panels to cover your energy requirements. Polycrystalline cells also suffer more from temperature fluctuations and therefore have a shorter lifespan than monocrystalline.

That being said, polycrystalline panels are much cheaper than mono cells, making them ideal for those on a tight budget.

Thin-film cells

Although the least efficient of the three types of solar cells discussed here (topping out at around 7 per cent), thin-film solar panels require less material to make and are therefore the cheapest option. They are produced by transferring a thin film of silicon onto another material – usually glass.

Thin-film panels are usually only recommended for installations where space is not an issue due to their lower efficiency and they tend to degrade quicker than crystalline cells, so they are not typically used for residential buildings. However, they perform very well in low-light conditions and have even been found to produce electricity in bright moonlight.

What should homeowners consider when deciding if solar panels are right for them? – David Hilton, Energy and Renewables Expert

Homeowners wanting to install solar panels need to be sure the panels can be installed securely to a south-facing roof. A west- or east-facing system will still work but may be around 20 per cent less effective than a south-facing array in the same location.

Solar panels do not usually require planning permission, as they are installed under the General Permitted Development Order (GDPO), which is often simply referred to as permitted development. You can fit 16Amps of panels without permission from the network operator. This is effectively 3.72kW, or around 10 panels. If you have a three-phase electric supply, then you can fit three times that amount.

Once the panels are installed, it is then up to the homeowner to maximise the use of the energy generated. The obvious item here is the use of a battery. A battery can certainly help use daytime generation when the sun goes down and the panels are not working, especially if you are not at home during the daylight hours. You do, however, need to calculate the cost of the battery and make sure the system does indeed still pay for itself.

The next thing you can do is add an energy diverter device which redirects excess energy from the solar panels to a water cylinder immersion heater. When you need new appliances such as washing machines, tumble dryers or dishwashers, it makes sense to get appliances that can be remotely controlled through an app. They can then be pre-loaded before you leave the home and programmed to start at specific times later in the day, hopefully when the sun is at its peak and your panels are producing the maximum amount of electricity.

There are ideal conditions to keep in mind when determining your home’s suitability for solar panels. (Adobe)

Solar panels are effective in the UK, and can even work on cloudy days, but that doesn’t mean to say they are suitable for every household. To work out if your home is suitable, consider the below.

The angle of your roof matters when it comes to installing solar panels on your home, as it can impact their efficiency. So can the geographical location of your home.

The orientation and angle of your roof determines how much sunlight your solar panels will receive. The optimal roof angle is between 30 and 40 degrees – studies suggest that solar panels at these angles maximise sunlight exposure and subsequently generate more electricity.

Another factor to consider is which way your roof is facing. In the UK, south-facing solar panels will generate more energy than other orientations and save you the most money on your energy bills.

The below table shows solar panels’ efficiency according to their angle, tilt and location in the UK. The percentages in the table show the efficiency you can expect.

After determining your roof angle and orientation, it’s a good idea to assess whether your roof is shaded and if it is, between which hours of the day this takes effect.

In order to maximise your solar panel system, it’s ideal for your roof not to be shaded during peak sunlight hours. In the UK, these hours fall between 10am and 4pm. If your roof is shaded during these hours, you may not be able to generate enough electricity to power your home. However, if your roof is only shaded for a small proportion of these hours, solar panels could still be beneficial for your home.

Installing solar panels comes with many benefits, the main one being saving money on your energy bills. With that being said, it’s important to consider if your roof has enough space for the size of system required to meet your household’s energy needs.

Throughout our research, we found the average UK household requires a 4kW system, which means homeowners would need 29㎡ of available roof space.

Solar panels add a considerable amount of extra weight to your roof. It’s easy to check how much each panel weighs before you make any purchasing decisions, as every manufacturer discloses this information on their product specification sheets.

To give you an estimate, we’ve calculated how much the average solar panel system weighs. An average UK household requires a 4kW system, which consists of roughly 16 panels; this could weigh up to 280kg.

There’s no simple answer to whether solar panels will affect your home insurance policy, but you should be aware of the following points:

• You do need to tell your insurance provider if you are installing or have installed panels, either when you take out the policy or in the event of having them installed
• Solar panels are an asset, so this may affect your premium
• Installing solar panels would likely affect the cost to rebuild your home if required, and this could also affect your premiums

With that being said, most insurers will include solar systems as standard, so don’t let that put you off. By notifying your insurer, they can make sure that you have sufficient cover to replace them should you need to.

It’s a common myth that solar panels don’t work very well in the UK, which has a lot of cloudy days and a relatively long winter season. However, although they work best on sunny days when there is the maximum amount of sunlight to convert, they do still work on cloudy days.

Solar panels can typically convert between 10 and 20 per cent of solar energy into usable electricity in the UK. They will convert more energy when they’re absorbing direct sunlight, but they can still produce electricity even with indirect light.

Below is a set of graphs showing the average amount of electricity the average 4kW system may have produced each month in 2022, based on sunlight data from the Met Office.

North of England

South of England

Midlands

East Anglia

England North West and North Wales

England East and North East

England South West and South Wales

England South East and Central South

Scotland North

Scotland East

Scotland West

All solar panels quote a maximum power output figure, measured in watts (W). This figure is recorded under ‘Standard Test Conditions’ (STC). As an example, a 400W panel in three hours of testing should produce 1,200 Watt-hours, or 1.2kWh, of electricity.

The power output of the solar panels used will determine how many you need to support the energy used in your home. If you choose panels with lower output, you’ll need to install more of them. If cost is an important factor, make sure you consider how this will affect installation costs, since more panels may mean more mountings and wiring.

To get an idea of what your power usage might be, you can use the below chart to see what the average annual UK household usage per kWh is.

The environmental benefits (and downsides) of solar panels – David Hilton, Energy and Renewables Expert

Solar panels generate good, clean, sustainable energy from the light of the sun. There are no moving parts and, as such, the expected lifetime of the system can potentially be around 20 years or more. There may be the requirement to replace the inverter (the component which converts DC electricity to AC) at some stage during that time, but if the installation was done properly then you should have a good 20- to 25-year life expectancy from the system at a minimum, albeit with a very small depreciation of generation as the system gets older.

However, current PV panels are mainly made of glass, silicon and aluminium. These are all energy-intensive products, and the manufacturing process also requires a lot of energy. The solar system should therefore generate quite a bit of useful energy before it has paid its own embodied energy. Simply installing solar panels on your roof is not a solution in itself – you also need to use the power they generate.

That said, the generation from the panels will go back to the grid and add to it green energy generation, so it is not wasted – but if you, as the homeowner, want any kind of financial payback, then you do need to use as much of that generation as you can.

Many solar panels were installed in less-than-ideal situations during the Feed-in Tariff frenzy. The installations were often installed in haste and they ended up detracting from the architectural merit of the home, or worse, negatively affecting the structural or weatherproof integrity of the building.

To know how many solar panels your household needs, you’ll need to work out how much your energy consumption is – we’ve created a step-by-step guide to help you do this.

Step 1: How much electricity do you use?

To work this out you’ll need your electricity bill – either the paper version or on your online account. This will tell you how much electricity you use per month or per year. Either use the annual number or work out how much you use by taking your monthly consumption figure and multiplying by 12. The power you use is measured in kWh. Now divide this number by 365 to get your daily usage.

Example: Annual usage = 3,500kWh

3,500 ÷ 365 = 9.6kWh per day usage (or 9,600Wh)

Step 2: How much electricity do you want your solar system to generate?

Decide how much of your annual electricity consumption you want your solar system to generate. Generally, the more power your system generates, the higher the initial cost will be.

For this example, we have based our figures on a household that wants to be powered by solar entirely.

Household power usage per day = 9.6kWh (9,600Wh)

Required power generated by solar = 100 per cent

Step 3: How much sunlight does your house receive?

You’ll need to work out how many sunlight hours your home receives per day. Sunlight hours vary from day to day, month to month and region by region. The Met Office says the average sunlight hours in the UK in 2021 was 4.1.

3,500 ÷ 365 = 9.6kWh per day usage (or 9,600Wh)

Required power generated by solar = 100 per cent

Sunlight hours = 4.1 per day

Step 4: Solar panel power

Now, estimate the power from each solar panel in the system. Panels range from 200W to 450W for UK households. For this example, we’ll use 350W panels.

Our power usage per day = 9.6kWh (9,600Wh)

Required power generated by solar = 100 per cent

Sunlight hours = 4.1 per day

Panel power rating = 350W

Step 5: How much you’ll generate

Using these figures, we can work out our potential power generation per day. We’ll use this formula:

Solar panel watts x average hours of sunlight × 0.75* = daily Wh

*We use the 0.75 modifier to take into account any variables such as solar panels not in a perfect south-facing position or under shade for some of the day.

350W × 4.1 sunshine hours × 0.75 = 1,076.25Wh per day

Step 6: How many panels you’ll need

Now we need to work out how many panels we’ll need to cover our daily usage. To do this, simply divide the amount of energy we use per day (calculated at the beginning of this process) by the amount of energy our system can generate from the previous step.

9,600Wh ÷ 1,076.25Wh = 8.92 panels

So, in our example of a 350W panel, we would need nine solar panels to generate enough power to cover our electricity needs. Remember, you can always sell any unused electricity back to the Grid, so we would consider fitting 10 panels so we could pay off our investment quicker.

Although the cost may be the overriding factor when choosing solar panels, there are other important factors to consider when choosing the right system for your home.

The most important factors to consider are:

Efficiency and what factors affect it

Solar panels can typically convert between 10 per cent and 20 per cent of solar energy into usable electricity in the UK. Their efficiency is often used as a selling point by solar brands and each panel’s efficiency rating matters.

Solar panel efficiency simply means the percentage of energy collected from the sun’s rays that can be converted into usable electricity. Therefore, the higher percentage that your panels are rated, the more electricity to power your home they will produce, resulting in lower energy bills and potentially even electricity you can sell back to the grid.

Power degradation and lifespan

Another feature you should take note of, which is usually included in a solar panel’s specifications, is its power degradation and lifespan. Power degradation refers to the gradual loss of usable energy your panels can generate. This happens year after year, and solar brands disclose this information within their product datasheets.

Product warranty

Solar panels have an average lifespan of 25 years. Although they can last longer than this, their efficiency will have decreased significantly. Since the panels have a relatively long lifespan, it’s advantageous for them to have a long warranty – ideally as many years as they are expected to last.

Our researchers found the average warranty offered by solar manufacturers and companies is 15 years, with the highest being a lifetime guarantee.

Size

Our researchers compared hundreds of solar panel datasheets and discovered there’s no standard size for solar panels. This means you’ll need to know your roof’s size or have an installer measure it for you in order to know how many solar panels will fit. But remember, you’ll need to take into account how many panels your household needs to meet your energy consumption requirements.

With any new investment or purchase, sometimes knowing where to look or which manufacturers or companies to trust is the hardest part. We’ve spent hundreds of hours researching different companies, manufacturers and their panels to find out which brands are trustworthy and worth considering.

We consider the following solar companies and manufacturers to be trustworthy, with products worth considering.

Project Solar is the largest and most accredited solar manufacturer in the UK and has installed more than 45,000 panels nationwide. The most outstanding feature the company offers is a lifetime guarantee for all of its products. This is far better than most other solar manufacturers, making installing its panels an attractive investment.

Project Solar receives a 4.3-star rating from Trustpilot, with more than 3,500 customer reviews – 75 per cent of which are five-star rated. Many of those reviews have praised the company for its installation process and its customer service. The manufacturer has won multiple awards, including Company of the Year, European Installer of the Year and Best Project Partner.

Its solar panels reach optimal performance even in low light conditions, and its Evolution Titan 445 solar panel has an efficiency of 21.4 per cent – one of the highest efficiencies on the market.

Project Solar is one of the most expensive solar manufacturers and its specific prices are only available upon request since the company bases prices on an entire solar panel system as opposed to per panel. However, its panels offer some of the highest efficiency ratings and warranties, so are good value for money.

SunPower is a US-based solar company providing some of the best solar panels in the industry. The company offers a generous 40-year warranty on its products, so you can be sure that your investment is worthwhile when installing any of its panels.

The company is best known for its SunPower Maxeon panels, which are highly efficient and have some of the lowest power degradation rates. Its 450W panel comes with an outstanding 22.2 per cent efficiency, and the company claims its panels have a higher efficiency than most other panels throughout their 25-year lifespan.

It receives a 2.8-star rating from Trustpilot, and although this is a relatively low score, there were only 249 reviews at the time of writing. Customer reviews praised the company for its simple installation process and knowledgeable advisors.

SunPower’s panels are fairly priced, and although not the most expensive, a 400W panel costs around £400. The savings you could make from its panels do justify its price points when you consider their high efficiency and long product warranty.

Founded in 2005, JA Solar has 12 manufacturing bases and its panels are available in more than 135 countries and regions. The company has a wide range of solar panels that touch varying price points. In fact, it’s fair to say its pricing is competitive compared with other companies, and throughout our research we discovered a 540W panel was priced at just over £200.

Although its pricing is competitive, its product warranties are not the longest on the market – on average, around 12 years. This is something to consider, should you decide to install JA Solar panels. Most of its panels are equipped with over 20 per cent efficiency and have been optimised to work well, even in low lighting.

Our researchers found there was no Trustpilot rating for JA Solar, however, this is not necessarily a bad thing. Very few solar companies are available on Trustpilot.

Once you’ve worked out which solar panels are right for your home and the size of system you require, the next step would be to have them installed. But before you dive in, you’ll want to find yourself an MCS-accredited installer.

The Microgeneration Certificate Scheme (MCS) is a scheme that quality-assures both products and installers of renewable technology. The scheme was government-owned up until 2018 and has certified more than 2,000 installers in the UK.

The MCS scheme isn’t mandatory, which you should bear in mind when it comes to choosing an installer. However, by choosing an MCS-accredited installer, you can trust they have the experience needed to do the job well. It should also be noted that, in order for your solar system to be connected to the grid which allows you to sell surplus energy, your installer must be MCS-accredited.

It’s best to source quotes from multiple installers and compare them, as well as consider their accreditations and experience.

Installing solar panels is a multi-step process, but your installer will talk to you about what will happen and when. (Adobe)

Once all of the planning and certification are complete and you’ve chosen your installer, the next step would be to receive your installation date. On the day of installation, you might want to oversee the process, and even if you don’t, it’s good to know what to expect.

Step 1: Erect scaffolding

A day or two before installation begins, a team will erect scaffolding around your house. This allows the installation team safe access to your roof and is a legal requirement. To avoid any unwanted fees, you should make sure the cost of the scaffolding is included in the price when you receive your quote, this will vary between installers, and you should double-check if this is included as standard.

Step 2: Roof team arrives

Once the scaffolding is safe and secure, your roof team will arrive with your solar panels – at which point you should check that they have brought the correct panels. You can check them by locating the sticker on the back, which outlines the model number, make and output.

Step 3: Attach the anchors

In order to attach your solar panels to the roof, your installer will need to first attach anchors. The anchors are brackets that hold the rails on which your panels will be mounted. The roofers will first remove a roofing tile for each anchor and screw the anchor brackets into the rafters of your roof.

The roofing tile can then be slotted back in as normal and rest onto the long arm of the anchor. A small bit is all that sticks out from under the tile, which is where the rail sits.

Step 4: Attach the solar panel rails

The frame for your solar panel system is made of lightweight aluminium rails – cut on-site by your installer to fit the size of your roof. The rails will be secured to each anchor bracket and secured with two bolts running vertically and horizontally across the roof to form a frame, where your panels will sit.

Step 5: Install the solar panels

At this point, your roof has now been prepared and your solar panels can be installed. Each unit will be mounted to the roof frames via a clamp. Once your installer is certain your panels are in the correct positions and are placed at optimal angles, they can be secured and tightened.

Step 6: Setting up the electrics

The final step requires a certified electrician, who will connect your pre-wired panels to your inverter. Usually, the inverter is installed in your loft. The inverter is what converts the direct current (DC) electricity that’s generated by your solar panels into usable alternating current (AC) electricity that can then be used to power your home.

After having your solar panels installed, and throughout their lifespan, it’s a good idea to carry out regular maintenance. Luckily, they require minimal maintenance and you only need to factor it into your schedule annually.

To maximise your panels’ lifespan, essential maintenance should include:

• Removing old leaves and tree branches
• Hosing them down to remove debris (never use a sponge, as this will damage your panels)
• Get them checked regularly by a certified service provider