Solar water heating vs solar PV: What’s right for you?

Thinking about going solar but not sure which system suits your home best? You’re not alone. For many UK homeowners, the choice between solar PV (which generates electricity) and solar water heating (which warms your water) isn’t immediately clear.

Both options can help you cut bills and rely less on the grid – but they work in very different ways, and choosing the wrong one could mean missing out on the real savings your home needs.

In this guide, we’ll break down the difference between solar PV and solar thermal systems, compare costs, performance, and maintenance, and help you decide which one is the better fit for your property.

Jump to:

• What’s the difference between solar PV and solar thermal?
• How each system works
• Is solar thermal or solar PV better for your home?
• Costs, lifespan and maintenance
• UK solar support schemes you should know about
• Solar PV vs solar thermal: Final thoughts
• Get a solar PV installation with Grant Store

What’s the difference between solar PV and solar thermal?

The two main types of solar systems available for homes in the UK are solar photovoltaic (PV) and solar water heating, also known as solar thermal. While both use daylight, they serve very different purposes.

• Solar PV panels convert sunlight into electricity, which can power your lights, appliances, and even charge an electric vehicle.
• Solar water heating systems use sunlight to warm water, typically for your taps, showers, or heating system.

The key difference? Solar PV = electricity. Solar thermal = hot water. Choosing the right one depends on your household’s energy use and priorities.

Solar thermal vs PV: How each system works

Solar PV systems generate electricity from sunlight, while solar thermal systems use sunlight to heat water for your home. Both are roof-mounted but serve different energy needs. Let’s take a closer look at how each system works.

How solar PV panels generate electricity

Solar PV panels are made up of photovoltaic cells, usually from silicon. When sunlight hits these cells, it creates a flow of electricity through a process called the photovoltaic effect. This generates direct current (DC) electricity, which is then converted into alternating current (AC) by an inverter – the type used in your home.

This electricity can be:

• Used immediately in your home and to heat water
• Stored in a battery system
• Exported back to the grid for payments under the Smart Export Guarantee (SEG)

PV panels work year-round and are ideal if your goal is to reduce electricity bills and increase energy independence.

How solar thermal panels heat your water

Solar thermal systems (also called solar water heating systems) use collectors – usually flat-plate panels or evacuated tubes – mounted on your roof. These absorb sunlight and transfer the heat to a fluid (usually a mix of water and antifreeze) that flows through the system.

This heated fluid moves to a coil inside your hot water cylinder, warming the water for use in your home. It works alongside your existing boiler or immersion heater, topping up when sunlight alone isn’t enough.

Solar thermal is highly efficient at heating water and is best suited for homes with high hot water demand.

Is solar thermal or solar PV better for your home?

The best system for your home depends on your energy use. If your main priority is reducing electricity costs, solar PV is likely the better option. If you use a lot of hot water and want to cut those heating bills, solar thermal may suit you better.

Solar PV is best for…

• Homes with high electricity use (e.g. EV charging, electric heating, home offices)
• Households looking to reduce energy bills year-round
• Properties with good roof space and minimal shading
• Homeowners wanting to sell surplus energy back to the grid via SEG
• Those considering battery storage for more energy savings

Solar water heating is best for…

• Homes with high hot water demand (e.g., families, multiple bathrooms)
• Properties with smaller roof space or lower electricity use
• Households using gas, oil, or immersion heaters for water
• Homeowners looking for a lower-cost solar option
• Those already using a hot water cylinder system

Solar hot water vs solar electricity: Costs, lifespan and maintenance

Solar PV systems tend to cost more upfront but give you more ways to save money and use cheaper energy. Solar thermal systems are generally cheaper to install, but are limited to heating your water. Here’s how the two compare in terms of cost, lifespan, and upkeep:

Installation costs

Solar PV: Installation typically costs between £6,000–£15,000, depending on system size, panel type, and whether extras like battery storage are included.

Solar Thermal: Costs are usually lower – around £3,000–£5,000 – as fewer panels are needed and the system is less complex.

PV systems qualify for the Smart Export Guarantee (SEG), which lets you earn by selling unused electricity back to the grid – something solar thermal doesn’t offer.

Expected lifespan

Solar PV panels: Most solar panels come with a 30-year performance guarantee, with little drop in efficiency over time. With the right care, they could last even longer. Inverters may need replacing after 10–15 years.

Solar thermal systems: Typically last 20–25 years too, but performance depends more on fluid quality and regular system checks.

Maintenance requirements

Solar PV: Low maintenance, mainly visual inspections and keeping panels clean. An annual service is recommended.

Solar thermal: Requires more frequent maintenance – including fluid top-ups, pump checks, and occasional servicing – to maintain the best performance.

While both systems are durable, solar PV is generally easier to maintain long-term and has fewer moving parts.

UK solar support schemes you should know about

Several UK schemes can help reduce the cost of going solar and improve your long-term return:

• Smart Export Guarantee (SEG) – Only applies to solar PV. Lets you earn for the unused electricity exported to the grid.
• VAT Relief – As of 2022, zero VAT is applied to energy-saving materials, including both PV and solar thermal systems.
• Renewable Heat Incentive (RHI) – Previously supported solar thermal but closed to new applications in 2022. Some households may still benefit if they applied earlier.
• ECO4 and GBIS – Broader energy efficiency schemes that can provide financial support for solar upgrades for eligible homes.

While grants are helpful, the real value lies in long-term savings. Solar PV can lower your electric bill, increase energy independence, and generate passive income through the SEG – giving it a financial edge in most UK homes.

Solar PV vs solar thermal: Final thoughts

Still weighing up solar water heating vs solar PV? Here’s the short version:

• Choose solar PV if you want to cut electricity bills, power your home more sustainably, and make the most of export payments via the SEG.
• Choose solar thermal if your main focus is reducing the cost of hot water, especially if you already have a compatible hot water cylinder.

Both systems can reduce your energy costs and carbon footprint – but the right fit depends on how your household uses energy. Not sure which is best for your home? That’s where we come in.

Get a solar PV installation with Grant Store

If you’re looking to cut electricity bills, power your home more efficiently, and take control of rising energy costs, solar PV is the smart move.

At Grant Store, we specialise in high-quality solar PV installations across the UK. From helping you choose the right setup to a smooth, hassle-free install, our team is here to guide you every step of the way.

Reduce your energy bills, future-proof your home, and spread the cost with our All-Inclusive finance package – repairs and maintenance included!

Get your free, online solar quote today and take the first step to cheaper energy.

We are a UK leader for solar PV installations; we don’t currently offer solar thermal services. For homes and businesses across the UK, solar PV installations are the smarter, more cost-effective way to power your home. If you’re ready to make the switch to cheaper, greener energy, get in touch for your free quote.