How To Generate Hot Water From Solar Panels


Jack Ayre

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It’s no secret that solar panels are the future of greener electricity. Many homeowners install solar PV to reduce their electric bills.

You may be surprised to know that most homeowners don’t use all the solar energy that their panels generate. The unused energy is exported back to the grid.

But did you know you can reduce your bills by using solar panels to heat your water? This way, you can use all the energy that your panels generate to get free hot water and save on your energy bills.

Here we outline how you can make the most of your solar system by generating hot water via solar panels.


How Can I Get Hot Water From Solar Panels?

Solar water heating, also known as solar thermal, can provide you with free hot water. They do so by absorbing free energy from the sun and transferring it to the water you use in your home. In other words, you’ll have free hot water!

Overall, solar thermal works in collaboration with your conventional water heating system. The solar collectors convert the infrared waves into heat. After that, the system uses the energy to preheat the water. The system then feeds the water into a storage cylinder or directly into your combination boiler.

Solar thermal technology reduces the amount of electricity or fuel needed to make the water hot enough. That can save you a fortune on your bills and reduce your overall carbon emissions.


What Are The Types of Solar Water Heaters?

Solar water heaters mainly consist of two parts: the collectors and the storage tanks. Moreover, there are two types of solar thermal systems: active and passive. Let’s check out each type in detail.

Active Solar Heating

Active solar heating systems come in two variations. The first variation is direct active circulation. In that system, the pumps circulate the water in your house through the collectors. Then, they circulate the water back into your home.

Direct circulation systems work well in areas where the weather isn’t extremely cold or cloudy.

The second type is indirect active circulation. In that system, the pumps circulate a heat-transfer fluid through the collectors and a heat exchanger. The liquid carries the heat, and then it transfers it to the water that flows into your house.

The indirect system is perfect for areas that are prone to freezing temperatures. That’s because the heat-transfer liquid doesn’t freeze.

Passive Solar Heating

Passive solar heating is slightly less efficient than active systems. However, it’s also cheaper and might last longer.

Generally, there are two types of passive solar heating systems: thermosyphon and integral collector-storage passive.

Thermosyphon systems heat the water in the collector. Then, water flows through the pipes whenever you open a hot water tap.

On the other hand, the integral collector-storage system has a transparent tank that allows the sun to directly heat the water. Therefore, it doesn’t work particularly well in freezing climates.


What Are The Types of Solar Thermal Collectors?

Solar thermal collectors are panels that can produce hot water. Overall, there are two types of these collectors: flare plate and evacuated tube.

Let’s talk about each type in detail.

Evacuated Tube Thermal Collectors

Evacuated tube collectors are lightweight and can do well in cloudy conditions. That’s because they demonstrate high efficiency in low-radiation situations.

The collectors typically consist of individual tubes mounted on a frame, which means they require on-roof installation.

Flat Plate Thermal Collectors

Flat plate thermal collectors are heavier and more rigid than evacuated ones. They have a robust, box-like design, which means you can install them on-roof or in-roof.

Additionally, they tend to be less expensive than evacuated tubes. The problem is that the hot water the flat plate collectors produce will be at a lower temperature.


Pros of Using Solar Water Heating

A solar thermal system can provide you with tons of benefits. Here are some of them:

It’ll Save You Money

Solar water heating systems can help you save on energy bills. No matter the type of energy you use to heat your water, solar thermal systems are cheaper in the long term.

We understand that installation might be costly, but the savings add up over time. On average, solar water heating can cut your hot water bills down to 50%.

The System Doesn’t Require High Maintenance

After installation, you won’t have to worry a lot about maintenance because most types of solar heating systems require little to no maintenance

It’s an Environmentally Friendly Option

If you use fossil fuels to heat your water, you need to understand that it produces gases that harm the environment. While electricity is a cleaner energy source, it still might cause environmental pollution, and it’s costly. Solar thermal technology is environmentally friendly, as it doesn’t release any harmful emissions. 


Cons of Using Solar Water Heating

Solar water heating has some cons that you need to consider. Let’s check them out.

The Installation Costs Might Be High

As with PV, installing a solar water heating system has high upfront costs. The exact cost will depend on the type of system you want to install and its capacity.

However, you need to understand that these systems last for years and can save you a lot of money in the long term. Keep that in mind when making your decision.

Not All Houses Are Suitable

Unfortunately, you must have a suitable boiler with a cylinder to install a solar thermal system. In addition, most heating systems require a solar panel facing south to work efficiently. Having shade on the roof can affect heating efficiency.

Luckily, you can make your house suitable for installation with some adjustments.

The Efficiency of Heating Depends on the Climate

The most important factor to consider before making your decision is the weather in the region. The performance of the system depends on the climate.

Generally, solar thermal systems don’t require the sun every day to generate heat. Most of them include a backup heater.

In other words, you’ll have access to hot water, even on the cloudiest days. However, the performance of the system won’t be the best.


Is My Home Suitable for Installing Solar Water Heating?

Unfortunately, not every home is suitable for solar water heating. Generally, if you have a hot water cylinder, chances are you can install a solar thermal system.

However, there are other things that you need to consider. Let’s check them out.

A Compatible Boiler

Combination boilers don’t have separate cylinders. Therefore, the boilers must support having pre-heated water directly poured into the boiler. If your boiler doesn’t support that, you’ll need to install a separate cylinder to be able to use the solar thermal system.

Solar Panels Requirements

When installing solar panels, they should face south. South-east and south-west can work in some situations. Further, the installation requires around two to five square meters of free space on your roof. Keep in mind that any shading from chimneys, trees, or other buildings might reduce the output of the panels.

Your Roof Compatibility

Solar panels can be heavy. Therefore, your roof must be strong enough to carry the extra weight.


Should I Install a Solar Water Heating System In My Home?

If you don’t mind the upfront installation costs, you should consider installing a solar water heating system in your home. You also need to consider the weather in your area.

In cloudy areas, solar heating isn’t the best idea. Other than that, you’ll be saving a lot of money. Not to mention how environmentally friendly it is.


How to Make the Most of Your Solar Heating System?

There are many ways you can make the most out of your solar thermal system. Here are some of them:

  • Insulate the pipes and the water tank to minimise heat loss.
  • Make sure to heat the water tank to more than 60% once a week to avoid any build-up of bacteria.
  • Consider switching most of your hot water usage to the evening, as the water will have enough time to heat up.
  • Carry out regular maintenance checks to make sure that everything is working efficiently.
  • It’s essential to follow the installer’s instructions and contact them if you have any questions.


Solar Hot Water FAQs

Can PV panels heat water?

Solar photovoltaic modules, also known as PV, generate electricity when exposed to light. On the other hand, the panels that can heat water are known as thermal collectors.

How much water can solar panels provide?

The amount of water depends on its type and capacity. It also depends on the efficiency of the system and the climate.

In summer, the system might be able to provide you with almost all the hot water you need. However, in winter, it can provide you with roughly half of your hot water requirement. 

How much money can solar water heating save?

The amount of money the system can save depends on its efficiency, your hot water consumption, and the size of your home. A well-installed and properly maintained system can save an average of £100 to £115 a year for a medium-sized system.

How to choose the right solar heating system for your home?

Choosing the right solar thermal system can depend on many factors. Here are some of them:

  • The average amount of hot water you use
  • Your budget
  • The weather in your region
  • The type of existing water heating system and boiler


After considering these factors, you can select a suitable heating system for your home. All in all, you can always consult a professional on which type to pick.

Do I need planning permission to install solar thermal panels?

In most cases, you won’t need planning permission to install a solar water heating system in the UK.

For houses listed as buildings, you need to contact your local council to make sure you don’t need to apply for planning permission. In addition, a large heating system might require permission.

Solar Hot Water Summary

Generating hot water from solar panels can provide you with a lot of advantages. For starters, the system will save you a lot of money on heating bills. 

On top of that, solar water heating is environmentally friendly, as it produces less carbon emissions. Not to mention how the system requires little to no maintenance.

If you don’t mind the high upfront costs of installation, you should consider getting solar thermal panels. More importantly, you need to choose the right type of heating system, according to the weather in your region, your budget, and the average amount of hot water you use.

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Born in North West England, Jack kicked off his career in the insurance arena, dealing with claims for three years. Always up for a challenge, Jack leapt out of his comfort zone and embarked upon 5 years of excitement with the military.

Working for the Ministry of Defence, Jack specialised in counter-terrorism which took him to places such as Dubai, Oman, Iraq, Norway and Bahrain. During this period he worked with various Governments implementing strategic operations to prevent terrorism.

After travelling around various countries Jack increasingly came across various forms of solar from large solar farms to domestic solar panels. From here Jack took a keen interest in all things solar and started reading about the technological capabilities with a view to entering the industry after his career in the Ministry of Defence.

Once home after 5 fruitful years, Jack had 3 months leave in which he immersed himself in a solar crash course and got applying for jobs within the solar sector. He came across ESE Solar, a long-established forward-thinking company whose head office was only a stone’s throw away from him. He picked up the phone to see if there were any vacancies and within a week had a successful interview and obtained a full-time job, starting in the technical team.

Within the first few months, Jack onboarded in various online courses during work and social hours to speed up his knowledge of all things solar. Due to his strong work ethic and thirst for knowledge Jack was promoted to Head of Technical at ESE Solar. He currently leads the team and oversees the product development of new technologies within the company alongside assisting where necessary on their maintenance department.

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