Solar Panels UK - Buying Guide

The UK solar energy market is set to see notable growth between now and the end of the decade.

Data from Statista projects solar energy generation will increase from 13.5 terawatt hours in 2023 to 15.6 terawatt hours in 2029.

With the government eyeing 100% clean and affordable electricity by 2030, a recent YouGov poll has highlighted strong support for expanding solar panel use. The same poll found that 86% of respondents have a favourable view of solar energy in general.

If you’re thinking of having a solar array added to your property, you’ll want to consider aspects such as the number of panels you may need, the potential costs involved and the pros and cons.

This here is your ultimate guide to solar panels, providing you with all the key knowledge needed to make a more informed choice if considering a solar setup. Let’s dive in!

How Solar Panels Produce Electricity

On a basic level, solar panels work by harnessing the energy of the sun through photovoltaic technology. For most designs, the cells contained within a solar panel harness sunlight (in varying degrees depending on the weather and other factors) to create electricity.

In other cases, a different setup is present. For example, one alternative design comes in the form of solar thermal panels. These are used to heat up water inside a hot water tank to heat a home or offer hot water for direct use.

These panels feature flat plate panels or evacuated tube collectors instead as a means of harnessing the sun’s power.

Returning to traditional solar panels, the electricity generated by the photovoltaic or PV cells comes in the form of direct current or DC. Since UK households require alternating current or AC electricity, an inverter is needed to convert the initial DC electricity into AC.

The AC electricity can then be used to at least partly meet a property’s electricity demands at a given time. That said, if you have a solar battery installed, it’s possible to store solar energy for use at a later point. How long a solar battery can store electricity will differ depending on the product and brand in question.

Types Of Solar Panels

There are several types of solar panels. Monocrystalline and Polycrystalline solar panels are the most common options, categorising the nature of the solar cells. Other types include transparent solar panels and solar thermal panels.

Monocrystalline

Monocrystalline solar panels feature solar cells with one silicon crystal each. In contrast, as you’d guess, polycrystalline panels have cells that utilise many silicon crystals. In the latter case, the silicon crystals are merged through melting.

Returning to monocrystalline panels, these are known for being more efficient than polycrystalline panels though they are more expensive.

Monocrystalline panels offer an average lifespan of 30 to 50 years. That said, as we’ll discuss in more detail later, many solar panels will need replacing after 25-30 years due to declining efficiency from wear and tear.

Polycrystalline

While not as efficient as monocrystalline panels on average, polycrystalline panels are usually more affordable while having a greater capacity to cope with high temperatures.

Polycrystalline panels come with a life expectancy of 30-40 years, though again they will likely need replacing quite a bit sooner. Given the differing life expectancies, polycrystalline panels will often need to be swapped out for new units somewhat sooner than monocrystalline panels.

Transparent

While less common and significantly less efficient, transparent solar panels may be right for some households, though they are more often used for commercial properties.

Notably, transparent panels can be placed atop windows, still allowing sunlight to enter while harnessing solar energy all the same.

With that said, transparent panels are costly and considering their downsides, it may not prove worthwhile unless you are particularly keen on a more seamless solar panel setup for aesthetic reasons.

Solar Thermal Panels

If you want to use solar technology to meet your home’s heating demands rather than your electricity requirements, solar thermal panels are the way to go.

Solar thermal panels can harness the sun’s energy before heating a mixture of water and glycol. This mixture is kept inside evacuated tube collectors or flat plate panels.

The heated fluid mixture subsequently travels to a hot water tank’s heat exchanger to pass on the heat energy. The water within the hot water tank is then heated up so that it can be used to create warm radiators to heat spaces within the property or/and for direct hot water use (e.g. hot sink taps, a warm shower, etc.).

While solar thermal panels can contribute significantly toward hot water needs, they are unable to meet a household’s entire hot water needs on a regular basis. However, in the summer, it’s possible they could meet 90-100% of a household’s hot water needs on a temporary basis.

The Advantages of Solar Panel Arrays

When considering whether or not to have solar panels installed, you’ll want to keep the benefits and downsides in mind. First, let’s discuss the upsides.

Reduction in Energy Bills

Firstly, having a solar system installed on your property can lower your energy bills for the long term.

While a solar panel installation will rarely meet a property’s entire energy demand, they can significantly cut electricity bills or (with the right setup) heating bills. In the case of the latter, a solar thermal heating system is needed.

Battery Storage to Power During Blackouts

Opting for solar batteries can provide you with the opportunity to store energy produced by your array for later use. This may come in handy to use electricity on a day when prices are on the rise for use at night time.

Of course, how long you can store electricity in solar batteries before needing to use it (and the extent to which you’ll be able to plan ahead) can vary.

That said, either way, you can use solar batteries to store energy ahead of a storm or another potential cause of a blackout, thus allowing you to use the stored electricity if the power is cut.

Eco-Friendly Power Source

Solar panels also stand out for being a great way of reducing your property’s carbon footprint. Photovoltaic technology allows households to harness solar energy while reducing their need to obtain electricity from the grid.

Solar panels can rarely meet a home’s entire electricity demand (or even energy demand if solar thermal panels or solar panels powering an electric boiler are considered – if either of these options is viable in your case).

With that said, even if a solar array met around 40-60% of your home’s electricity demand, you could then meet the rest of your electricity needs via a green energy provider. The same can often apply to an electric boiler.

As a result, you could virtually wipe out your carbon footprint if the aforementioned setup is feasible and appropriate for your home.

Always verify with suitable professionals before opting for a new home energy approach. Qualified professionals are also required for the installation work regardless.

Long Lasting With Limited Maintenance Requirements

Solar panels are also known for being durable with many units lasting for up to 25-30 years before replacements are needed.

This is unlikely to be the result of solar panels wearing down beyond repair but from their efficiency or/and output dropping to an extent that it is financially smarter to have them replaced (especially if efficiency levels continue to rise for new solar panels).

While solar panels should be serviced annually, maintenance work isn’t likely to prove a regular requirement.

The Disadvantages of Solar Panels

To offer a fair and balanced guide to solar panels it’s important that we lay out the downsides for your consideration too.

Costly Installation

While solar panels can pay for themselves in time, the upfront cost is a significant downside with most installations costing somewhere in the region of £3,000 to £8,000 in total.

Many Solar Panels Include Toxic Materials

Another downside of solar panels is that many feature toxic materials. As a result, in these cases, it isn’t true to say that solar panels are completely eco-friendly. This problem is proving more pressing lately as some solar panels installed in the 2000s are being thrown away.

Cannot Be Added to All Properties

Another consideration is that solar panels cannot always be installed on a property. Firstly, not every type of roof is suited to a solar panel installation. Ground-mounted solar panels are also an option though they can only be installed in suitable and sizeable garden spaces.

Therefore, not all properties will be appropriate for a solar panel installation. Thankfully, the vast majority will be, however.

Take Time to Pay For Themselves

With the average UK household spending about £900 per year on electricity bills and solar panels generally covering around 40% to 70% of a household’s electricity needs, a solar panel system is likely to save around £360 to £630 per year.

Since the average solar system costs between £3,000 and £8,000, it may take anywhere from 5 to 25 years.

How Many Solar Panels Do I Need?

The number of solar panels a property will require can differ depending on a range of factors. These can include the size of the property, your home’s electricity demand (while considering how much of your home you want to power through solar) and the type and efficiency of the solar panels you opt for.

Here are some examples of solar panel requirements based on property size and estimated solar system power requirements (i.e. the size of the solar system in KWS):

Property Description	Estimated System Size in KWs	Approximate No. of 300 Watt Solar Panels*
Terraced House with 1-2 Bedrooms	2kW to 3kW	6 to 10 panels
Terraced House with 2-3 Bedrooms	3kW to 4.5kW	10 to 15 panels
Semi-Detached House with 2-3 Bedrooms	3kW to 4.5kW	10 to 15 panels
Semi-detached house with 2-3 Bedrooms	4.5kW to 5.5kW	15 to 19 panels
Semi-detached house with 3-4 Bedrooms	5.5kW to 6.0kW	18 to 20 panels
Detached House with 4-5 Bedrooms	5.5kW to 6.0kW	18 to 20 panels
Detached House with 5-6 Bedrooms	5.5kW to 6.5kW	18 to 22 panels

*Again these are approximations since energy demand can vary among properties of the same size or/and same number of bedrooms. The number of panels needed will also depend heavily on how much of your energy demands you wish to meet through solar panels. Be sure to discuss these details with the installer or company you choose to hire.

Solar Panel Pricing

Individual solar panels generally cost somewhere between £200 and £450 in supply costs. Of course, a solar installation will generally need at least 8-10 panels. Beyond that, the labour price is likely to land somewhere in the region of £500 to £1,200.

Here are some examples of solar panel setups with cost breakdowns:

Size of System*	No. of Panels**	Total Cost	Labour Cost	Supply Costs
3kW	10	£2,500 to £5,500	£500 to £1,000	£2,000 to £4,500
4kW	13-14	£3,200 to £7,500	£600 to £1,200	£2,600 to £6,300
5kW	16-17	£3,800 to £8,850	£600 to £1,200	£3,200 to £7,650
6kW	20-21	£4,700 to £10,650	£700 to £1,200	£4,000 to £9,450
7kW	24-25	£5,500 to £13,450	£700 to £1,200	£4,800 to £11,250

*Please note that the number of panels needed is approximate to the system size on the left since most do not add up to precisely a given kW value with 300 watts each.

**This assumes solar panels with 300 watts each. While this is a common wattage level for solar panels, there exists a solid range on the market meaning that the number of panels a given project will require will depend largely on the product and brand you opt for.

The Best Solar Panel Brands On The Market

Among the top solar panel companies in 2024 to consider include SunPower, REA, Jinko Solar, Project Solar UK and JA Solar. Other notable names are LG Solar, Panasonic and QCell. Let’s consider the best brands on the UK market and their best solar panel products.

SunPower

U.S.-based SunPower is a globally successful solar panel manufacturer known for offering a wide range of solar panel products.

Founded in the 1980s, the company split into Maxeon Solar and SunPower five years ago. The Maxeon Solar brand is associated with the lineup found in the UK market. Their solar panels generally cost somewhere in the region of £200 to £600 per unit in supply-only costs.

The power output range of these panels is somewhere in the region of 330 watts to 440 watts. The brand offers a great product warranty range that lands between 25 and 40 years which is above average.

REA

Australian company REA is another top-of-the-market draw. Their panels usually cost somewhere in the region of £500 to £800. REA offers a product warranty and a performance warranty of 25 years each.

The company’s solar panel products offer output levels of 400 to 480 watts, this being an above-average output level range.

REA is known for offering durable solar panels. The company is also recognised for their inventive solar designs including panels with ‘advanced fusion solar tech’ that increases safety, reliability and energy production. This design means that their panels can absorb sunlight from the rear as well as the front to capture more energy from solar rays.

Qcells

South Korean solar panel company Qcells offers relatively low-cost solar panels with a price range of £150 to £200 per unit.

Among the reasons for the popularity of Qcells solar panels include their efficiency levels, capacity to cope well with the elements and durability.

The manufacturer’s product warranties range from 12 to 25 years with power outputs varying between 340 watts and 410 watts.

Project Solar UK

Project Solar UK is another force in the solar market these days. The brand has undertaken 45,000 solar panel and battery instalments across the UK to date.

Project Solar UK offers product warranties starting from 15 years and reaching up to lifetime warranties (e.g. the Evolution Evo Super Max 455). They offer performance warranties ranging from 25 to 30 years.

Some of the reasons you may want to consider Project Solar UK include their warranties, positive customer ratings (incl. 4.7/5 stars on TrustPilot) and finance options.

Viridian Solar

UK solar company Viridian Solar also stands out thanks to its durable solar panels with sleek, modern designs.

Along with aesthetically pleasing solar panels, Viridian Solar sells various solar connectors, EV chargers and more. Their panels are generally priced between £100 and £250 while their warranties range from 10 to 25 years.

Solar Panel Lifespans And Warranties

As mentioned earlier, solar panels usually last for up to 25-30 years. At this stage (and potentially sooner), solar panels have generally lost much of their efficiency.

The good news is that many solar panels come with warranties in the region of 20 to 30 years. However, warranties of around 10-15 years are also quite common whereas 30+ year warranties exist in rare cases (e.g. the SunPower Maxeon 3 has an incredible 40-year product warranty).

What About Grants And Funding For Solar Panels?

If you are based in England or Wales, you may be eligible for ECO4 funding to cover some or all of the costs involved in a solar system installation. ECO4 scheme funding is generally available to low-income households or/and properties with relatively low energy efficiency (e.g. EPC ratings of D, E, F or G).

Solar Panels FAQ

Q: How much maintenance work is needed with a solar panel installation?

A: While solar panels should be serviced annually, they are generally low maintenance. Along with annual servicing, consider having them cleaned (potentially as part of the servicing) once a year or even every six months.

Cleaning or even repair work may be needed abruptly such as after a major storm. In these scenarios, your solar array could become covered or partially covered in debris necessitating a significant cleanup to maintain their efficiency and effectiveness. Debris, of course, can reduce the capacity of a solar system to generate electricity by blocking sunlight.

After a major storm, it’s even possible that repair work will be needed. A professional may decide that the damage can be repaired or recommend having one or more solar panels replaced if needed.

Q: Is it okay to leave solar panels on all the time?

A: You can leave your solar panels on the vast majority of the time. That said, they should be turned off ahead of cleaning or maintenance work to avoid an electrocution risk. The only other scenario where turning off solar panels might make sense is if you do not intend to use them for many weeks or months.

It is best to leave this to a professional as they must perform maintenance work all the same. While cleaning may be done DIY, you should only do so if you are certain of what’s involved including all safety steps (e.g. wearing a safety harness if needed). The manufacturer’s instructions should be followed closely too.

Generally, the steps to turn off solar panels will include finding the appropriate switches in your meter box and turning them off. Only do this DIY ahead of cleaning solar panels if you are absolutely sure of what is needed. Otherwise, hire a professional to undertake all the required steps.

Q: Will I need planning permission to have solar panels installed?

A: If based in England or Wales, planning permission is only needed in certain cases (e.g. if your property is a listed building or it is either within the grounds of a site designated a scheduled monument).

The Planning Portal provides further details on when planning permission will be needed and when it will not (i.e., permitted development applies). Either way, you can always confirm with your local council.

The rules can differ for those based in Scotland or Northern Ireland. Contact your local council to find out whether your solar panel setup is permitted development if based in Scotland or Northern Ireland.

Q: How much do solar panels deteriorate after 20 years of use?

A: Solar panels do not generally break down fully after 20 years, however, they are likely to see a drop of around 10% in their solar output as compared with when they were initially installed.

Solar panels gradually see a reduction in their efficiency and output as a result of damage caused by UV rays and the elements (e.g. heavy snowfall, a rain storm, heavy wind etc.).

As solar panels decline over time, there will come a point at which it will generally make sense to have them replaced. The case for replacing them is likely to become two-fold as along with a reduction in output and efficiency, newer solar panels will likely see an increase in their initial quality in the years ahead as solar technology advances.

In most cases, households will find that after 25-30 years their solar panels will need replacing though replacement work may be needed sooner in some cases.

Q: Do solar panels still generate electricity on cloudy days? What about later in the day?

A: Solar panels can still harness energy from the sun (and produce electricity) when it’s cloudy, even if it’s overcast. That said, as you’d imagine, the amount of energy a solar system will harness is going to vary significantly depending on how much sunlight reaches the panels.

On an overcast day, solar panels tend to generate around 40% to 70% of the electricity they normally generate.

Beyond that, solar panels are more effective around midday when the sun is highest in the sky. Of course, every day will differ (with the above statement being more a rule of thumb) as it could be cloudy at midday before clear skies at 4 pm meaning that more sunlight may land on your panels later in the day.

All in all, though, solar panels tend to produce less electricity later in the day or early in the morning. They generate virtually no electricity at night, bar the small amount of reflected sunlight that may reach their surface by moonlight, though the quantities would be minuscule.

Lastly, it’s also worth mentioning that solar panels generate more electricity in the summertime due to longer days and often less cloud cover. On the other hand, solar panels usually generate the least electricity (on a season-by-season basis) in the winter months.

References

https://energysavingtrust.org.uk/advice/solar-panels/
https://www.greenmatch.co.uk/solar-energy/solar-panels
https://www.renewableenergyhub.co.uk/main/solar-panels
https://soly-energy.co.uk/blog/the-ultimate-guide-to-solar-panel-installation/
https://heatable.co.uk/solar/advice/solar-panels
https://heatable.co.uk/solar/advice/solar-panels