Solar Water Heating System Price & Installation Costs UK

Just as solar panels can be used to generate electricity to power household appliances, it’s also possible to employ solar energy to produce hot water. And not just in the way the sun melts your ice cubes. 

More specifically, solar water heating does not rely on solar panels that are used to turn the sunlight into electricity, instead solar thermal panels can harness the sunlight to warm water. 

Solar water heating utilises a combination of a solar thermal tube/panel system and a hot water or immersion heater. 

But how much can you expect to pay? And is it worth it in the UK (since we’re not exactly known for our sun hours)? 

Let’s explore...

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🔑 Key Points: 

• Solar water heating uses the sun’s energy to heat water stored in a hot water cylinder.

• The two main collector types are evacuated tubes and flat plate collectors.

• Most systems use a mixture of water and antifreeze circulating through the collectors and cylinder coil.

• In the UK, solar thermal usually provides around half of annual hot water demand on average.

• A typical system costs around £6,000 installed.

• It can reduce hot water energy costs and lower your home’s carbon footprint.

• It works best on a south-facing roof with around 5m² of sunny space.

• You’ll usually need a hot water cylinder and a boiler or immersion heater as backup.

What is Solar Water Heating?

A solar water heating system uses roof-mounted collectors to capture heat from the sun and transfer it into a hot water cylinder or thermal store.

That hot water can then be used for taps, baths and showers, just like hot water from a conventional heating system.

Instead, it normally works alongside a boiler or immersion heater, which tops up the water temperature when needed.

In other words, solar water heating is designed to supplement your hot water supply, not replace it entirely.

How does solar water heating work?

A solar water heating system starts with collectors mounted on your roof, flat roof frame, wall, or sometimes the ground. Inside those collectors, a liquid, usually a mixture of water and antifreeze, absorbs heat from the sun.

That heated liquid is then pumped through a coil in your hot water cylinder, where it transfers its heat to the stored water. The liquid then circulates back to the collectors and the cycle repeats.

There are two main types of collector:

• Evacuated tube collectors

These are made up of rows of glass tubes and are commonly installed on pitched roofs.

• Flat plate collectors

These are flat rectangular panels that sit on or in the roof and work in a similar way.

Both types can work well in the UK. The right option depends on your roof, budget and installer recommendation.

How much hot water can solar thermal provide?

Solar water heating can make a useful contribution to your home’s hot water supply, but it won’t usually cover everything.

On average, a typical system can provide around 50% of a household’s annual hot water needs. In summer, that figure can rise to around 90%, while in winter it may drop to around 25%.

That means solar thermal tends to work best in homes that:

• use a fair amount of hot water

• have space for a cylinder

• have a suitable roof

• are looking for a long-term energy-saving upgrade

Is solar water heating suitable for your home?

Solar water heating is usually most effective if your home has:

• around 5m² of roof space for the collectors

• a south-facing roof, although east- and west-facing roofs can also work

• minimal shading from trees, buildings or chimneys

• room for a hot water cylinder or thermal store

If you already have a conventional boiler and hot water cylinder, installation is often more straightforward.

In many cases, solar thermal is considered permitted development, although rules can differ for listed buildings, conservation areas and certain protected locations.

Still learning about solar panels? Explore our helpful guides on various topics, including solar panel grants, payback periods, the mechanics of solar energy, determining the number of panels you need, and solar car charging solutions.

How much does solar water heating cost?

A typical solar water heating system costs around £6,000 installed in the UK.

The final price depends on several factors, including:

• the size of the system

• the type of collectors used

• whether you need a new hot water cylinder

• roof access and installation complexity

As with most home improvements, the more straightforward the installation, the lower the cost is likely to be.

Running costs and maintenance

Solar thermal systems are relatively low maintenance, but they are not completely maintenance-free.

A more thorough check is usually recommended around every five years to flush the system and replace the heat transfer fluid.

Some homeowners also choose to have an annual service check for added peace of mind. It’s also sensible to keep an eye on the control panel for any fault warnings.

So while solar water heating is easy to look after, it still needs occasional servicing to keep it working efficiently.

Grants and funding

The Domestic Renewable Heat Incentive (RHI) closed to new applicants on 31 March 2022.

Households that were already accredited before the scheme closed can continue to receive payments for the remainder of their term, but new applicants can no longer join.

The current Boiler Upgrade Scheme does not support solar thermal. Instead, it covers technologies such as:

• air source heat pumps

• ground source heat pumps

• biomass boilers

So, if you are considering solar water heating today, you should generally assume that you will be paying for the installation without a dedicated UK-wide grant.

How to Pay for Solar Water Heating

The Streets knew it: A Grand Don't Come for Free - and neither do solar water heaters.

As you can see, solar water heaters don’t come cheap.

However, there are some ways of bringing down the cost of installation.

Purchasing a Solar Water Heater on Finance

Some companies allow homeowners to purchase a solar water heating system on finance once certain criteria are met.

Purchasing on finance is just another way of saying buy now and pay later. Which is preferable to overpaying now and buying later.

Usually, you’d need a good credit history to be eligible for this or at least no signs of bad credit over the past several years.

However, the details will vary depending on the company. What’s more, purchasing on finance usually means paying interest.

So, while this approach could save you plenty of money in the short term, it would likely cost you more in the long run.

Check out our complete guide on the costs of solar and whether solar is worth it in the UK here. 

Using a Loan

Another solution is to take out a bank loan.

Again, you’ll likely need to meet specific criteria to be eligible for a loan, and of course, interest will also apply. As we all found out in 2008, banks aren’t charitable institutions. 

While purchasing an appliance on finance can sometimes come with zero interest, loans are virtually never free of interest. 

Aside from taking out a loan, if you have a credit card, you may be able to use this to pay for a solar water heating system.

However, whether you want to buy now and pay later, take out a loan, use a credit card, or a combination of two or all three of these approaches, you should make sure that you can afford it.

If in doubt, it’s best to wait and save more before installing a solar water heater.

What about the RHI scheme?

Unfortunately, the domestic renewable heat incentive (RHI) scheme closed to new applicants in March 2022. If you were an applicant before then, we mostly wonder why you’re reading this article.

It offered both an upfront payment when a household joined the scheme as well as yearly incentive payments. 

This meant that under the RHI scheme, households could effectively save hundreds of pounds per year in heating costs if having a solar water heating system installed, rather than £40 to £100.

We have also reviewed the best solar panels and covered how long solar panels last in the UK. 

Pros and Cons of Solar Water Heating

So, what are the benefits and disadvantages of a solar water heating system?

[1] Reduces your heating bill

First and foremost, a solar water heating system can lower your heating bills which is people’s favourite activity with bills. After all, it costs nothing to run a solar water heater.

This means that if you have, say, natural gas heating, using a solar water heater to supplement your home’s hot water production would likely save you around £40 to £60 per year.

If you use another primary means of heating your home (e.g., oil, electricity, or LPG), you may save somewhere in the region of £50 to £100 a year in heating costs.

[2] Significant benefits in the summer

While a solar water heating system would likely meet around a quarter of your hot water needs in the winter, it could meet the majority of your water needs (perhaps about 90%) in the summer months.  And not only because you’re bound to spend more time outside…

[3] Lowers your carbon footprint

As with solar energy in general, a solar water heating system will mean fewer greenhouse gases entering the atmosphere. Fewer greenhouse gases mean colder winters, which also means you get more use out of your solar water heating. It’s a win-win!

Cons of Solar Water Heating: 

[1] Expensive upfront cost

As you saw earlier, having a solar water heater installed isn’t cheap.

Regardless of the size and type of system being installed, you’ll surely need to spend thousands of pounds. In any list of pros and cons, that’s a con.

The only exception would be if you were to use one of the alternative payment methods discussed in the previous section.

[2] It takes a long time to pay for itself

With average annual heating savings of just £50, it would likely take many decades for a solar water heater to pay for itself. 

In fact, for the average three-bedroom semi-detached house, it would take almost a lifetime (yours, not the system’s) to pay for itself. And leaving a legacy to the next generation is one thing, but a solar water heater probably isn’t that high on anyone’s list. 

So, clearly, if you want a solar water heater, it makes sense to do so as a very long-term investment and as a way of improving your home’s energy efficiency and lowering your carbon footprint.

[3] The output will vary

Aside from the fact that solar water heaters won’t likely be able to meet all your hot water demands, the output of a solar array will vary depending on the weather.

After all, solar panels produce a lot more energy on bright sunny days than they do on overcast ones.

Next Steps For Your Solar Journey:

When planning to install solar panels for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:

• How much do solar panels cost? 

• Are solar panels worth it for your home? 

• Is your roof suitable for solar panels? 

• What are the best solar panels available? 

• Is battery storage worth it? 

To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos, or read a customer case study to see how others have benefited from their solar installation. 

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