Solar Photovoltaic (PV) vs Solar Thermal Panels (UK)

While they might look similar at first glance, solar photovoltaic (PV) and solar thermal panels are different, each working differently to deliver unique benefits and outcomes. Solar PV panels generate electricity that you can use to power your home, while solar thermal panels capture the sun’s heat to provide hot water or support your heating system.

Understanding the difference between the two is key to deciding which option suits your household best.

In the UK, where energy costs are high and the push for greener homes is stronger than ever, choosing between solar PV and solar thermal panels can feel like a big decision. Ultimately, the right system for you depends on individual circumstances and needs.

By the end of this guide, you’ll have a clear picture of how each technology works, their benefits and which one is better suited for your home.

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How Do Solar Panels Work?

It helps to break down the basic science behind solar panels when trying to understand how they work. Solar photovoltaic, or solar PV, panels are made up of layers of semiconductor material, usually silicon. When sunlight hits these cells, it knocks electrons loose, creating an electric current through what’s called the photovoltaic effect.

This current is direct current (DC), which is then converted into alternating current (AC) by an inverter, safely powers your home’s appliances, such as your kettle. Even in winter, solar panels can still generate electricity, though they’ll be most effective in direct sunlight.

Benefits of Solar Panels

When comparing solar panels to solar thermal systems, it’s helpful to focus on the key benefits of each. Here are some of the top advantages of solar panels to keep in mind:

• You can generate your own clean, renewable electricity directly from sunlight, reducing your reliance on energy companies.

• Solar panels help cut your electricity bills by powering your home appliances for 'free'.

• They reduce your carbon footprint by producing energy without harmful emissions.

• You can add a battery to store electricity for use in the evenings or on cloudy days, so you use more of what you generate.

• Solar panels have the ability to potentially increase the value of your property by making it more energy efficient and attractive to buyers.

• Maintenance costs are usually low since solar panels have a lifespan of 25 years or more with little upkeep needed.

• You may qualify for solar grants and incentives such as the Smart Export Guarantee, which pays you for surplus electricity you send back to the grid.

Drawbacks of Solar Panels

• Solar panels work in winter and cloudy days, so you can still benefit from 'free' electricity throughout the year.

While solar panels offer many benefits, there are also some drawbacks to keep in mind:

• The upfront cost of solar panels can be significant, even though prices have dropped in recent years.

• Solar panel performance depends on sunlight, so you’ll generate less electricity on very cloudy days.

• Not all homes are suitable for solar panels. If your roof is shaded, in poor condition, or faces the wrong direction, panels may not work efficiently.

• Planning permission can sometimes be required, especially for listed buildings or homes in conservation areas.

• The payback period for solar panels can be several years, meaning it takes time to recover your initial spend through bill savings and any export payments.

How Much Do Solar Panels Cost?

According to The Renewable Energy Hub, the cost of installing a 4kW solar panel system typically ranges from £4,000 to £7,000. However, it’s important to keep in mind that many factors can affect the overall cost of solar panels. These include your roof size and condition, the type of panels you choose and any additional equipment like batteries.

Therefore, we recommend getting a personalised solar quote, as this is the best way to get an accurate idea of how much you would pay for your home.

Another aspect to consider in terms of costs is the Smart Export Guarantee (SEG), which pays you for any extra electricity your solar panels send back to the grid. This means you can actually earn money from the surplus power your system produces, adding further value to your investment.

It's also important to keep in mind that the UK government is actively encouraging the adoption of solar panels to help homes become more energy efficient and reduce carbon emissions. As part of these efforts, you can benefit from several grants and incentives designed to lower the initial cost of installation. For example, solar panel systems currently qualify for 0% VAT, meaning you don’t pay any added tax on the purchase and fitting.

How Do Solar Thermal Panels Work?

On the other hand, when you look at how solar thermal panels work, the key thing to know is that they don’t produce electricity like solar PV panels do. Instead, they capture the sun’s heat and use it to warm up water for your home. The panels, usually fitted to your roof, contain tubes or flat plates filled with a special liquid. When sunlight hits the panels, this liquid heats up and carries the warmth into your home’s hot water system.

The heated liquid then flows through a coil inside your hot water cylinder, transferring the heat to the water you use for showers, baths or taps. Once it has given up its heat, the cooler liquid is pumped back to the panels on your roof to be heated again, so the process can keep repeating. Ultimately, it helps you use less gas or electricity for water heating.

It's important to remember, solar thermal panels usually won’t provide all your hot water needs year-round, especially in winter when sunlight is weaker. However, they can supply a large share of your hot water in spring and summer, which can help to significantly reduce your energy bills.

Benefits of Solar Thermal

Now that we've looked at the advantages and disadvantages of solar panels, let’s explore the pros of solar thermal panels:

• Solar thermal panels efficiently capture the sun’s heat to provide hot water, reducing your reliance on gas or electric heating.

• They can significantly lower your hot water bills, especially in spring and summer months when sunlight is stronger.

• Solar thermal systems have a relatively low environmental impact by cutting carbon emissions linked to heating water.

• They work silently without noise or moving parts, requiring minimal maintenance over their lifespan.

• Solar thermal panels can be integrated with existing heating systems, providing extra warmth during colder months.

• The technology is well established and proven to last for many years with proper care.

Drawbacks of Solar Thermal

Let's now take a look at the cons of solar thermal panels:

• Solar thermal panels may not meet all your hot water needs year-round, particularly during the darker winter months.

• Initial installation costs can be high and may involve complex plumbing work.

• The system relies on a hot water cylinder to store heat, which takes up space inside your home, whereas solar panels do not.

• If the system isn’t properly maintained, components like pumps or cylinders can wear out and need replacement.

How Much Does Solar Thermal Cost?

According to The Renewable Energy Hub, the cost of installing a solar thermal system typically ranges from £3,000 to £6,000. While solar thermal systems are generally cheaper than solar PV panels, the price gap has narrowed in recent years as the cost of solar PV technology has dropped significantly.

Like solar panels, the price you pay for a solar thermal system depends on factors like the size of your home, the number of panels needed and the complexity of installation. Since solar thermal panels work alongside your hot water system, some plumbing upgrades may be required, which can affect the total cost.

It’s also worth noting that although solar thermal panels tend to cost less upfront, they typically produce heat rather than electricity. This means they won’t replace your electricity needs but can reduce your hot water heating bills significantly, especially in warmer months when they work at their best.

Solar PV vs Solar Thermal - What Are the Key Differences?

When comparing solar PV vs solar thermal, the main difference lies in what they actually produce. Solar PV panels generate electricity, which means you can power everything from your washing machine to your TV directly from sunlight. On the other hand, solar thermal panels are designed specifically to capture the sun’s heat and use it to produce hot water for your home.

Another key difference is how the energy is stored and used. With solar PV, you can add a battery to store electricity for when you need it most, like in the evenings. Solar thermal, however, stores heat in your hot water cylinder, making it immediately useful for things like baths, showers and washing up. Which one suits you better depends on whether your main goal is lowering electricity bills or cutting down on hot water and heating costs.

Finally, seasonal performance is worth considering. Solar PV panels will work all year, even under cloudy skies, although they won’t be as efficient. Solar thermal panels are excellent in summer and can often meet most of your home’s hot water needs during these months. In winter, however, they’ll usually provide part of the demand, and you’ll still need a boiler or other heating source to top it up.

Solar PV vs Solar Thermal - Which Will Suit Your Home Best?

If you’re looking to cut your electricity bills and invest in a technology that’s growing rapidly and will continue to be widely adopted, then solar PV panels are an excellent choice for your home. They generate electricity you can use for lighting, appliances, and more, helping you save money.

Also, solar panels are suitable for most homes in the UK, with a wide network of solar panel installers, including Glow Green, available to help you get started.

On the other hand, if your main goal is to reduce your heating bills by producing your own hot water, solar thermal panels could be a better fit. These systems capture the sun’s heat to warm water, cutting down the energy you spend on showers, baths and taps. Solar thermal often works alongside your existing boiler to provide a greener, more cost-effective way to heat your water.

You could also consider installing both solar PV panels and solar thermal panels if you want to benefit from generating electricity and heating your water through solar energy. However, it’s important to remember that combining both systems will involve a much larger upfront investment.

Another option to consider is an air source heat pump, which provides highly energy-efficient heating and hot water for your home. Like solar solutions, heat pumps can help reduce your energy bills and carbon footprint.

Ultimately, if you’re unsure which option, or combination, is best for your home and budget, it’s a good idea to speak with an expert like Glow Green. We can provide personalised advice and help you find the most cost-effective and efficient solution for your needs.

Solar Photovoltaic vs Solar Thermal Panels FAQs