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Can You Run an Immersion Heater from Solar Panels?

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Solar panels use the sun’s energy to generate electricity. They can be connected to the immersion heater on the tank of hot water using a gadget called an electrical diverter or Solar PV optimizer to generate free hot water.

Your excess solar energy will be delivered to the National Grid because solar PV panels frequently generate more energy than you can consume in a day. You can use this extra energy to run your immersion heater and cut your energy costs even more by using a solar power diverter.

Here, we’ll present the solar power diverter and explain how using it to power your immersion heater can maximize your solar savings. Find out the overall process of utilizing solar power by reading on!

How Does a Solar Diverter Work?

A solar diverter is a mechanism that directs any additional solar energy by an electrical device, typically an immersion heater for the heating of water or an electric heater. It measures the amount of solar power produced and the amount of electricity used by the residents in real time.

A solar power diverter can direct your excess energy toward warming your hot water tank. It automatically sends any excess energy to the grid—to your immersion heater. So, you need to buy this device if you want to heat water for free with solar energy.

The power is directed to the immersion heater if the energy from the sun is more powerful than the consumer power. Diverters for immersion are solar PV optimizers, power diverters, and immersion optimizers.

What Is Feed-in Tariff Payments?

With the Feed-in Tariff, producers or consumers are compensated for transferring extra electricity to the grid, which promotes investment in renewable energy sources. Thus, it rewards organizations for creating, utilizing, and conserving energy sources like wind and solar energy.

As part of this performance-based incentive, renewable energy vendors receive a fixed cost of electricity from a service supplier or grid worker for each unit of electricity they generate. The tariff aids in the advancement of renewable energy and environmentally friendly power generation technologies.

It makes no difference how much solar energy you send to the grid because you will still receive the same payment. You should conserve and utilize as much of the energy from the sun as you can, so, you’ll need to purchase less energy from a supplier.

Can Solar Panels Run an Immersion Heater?

If you use the electricity wisely, you won’t need to purchase units via the grid by running an immersion heater with the power of a solar panel, which may result in a reduction of costs and save money.

Solar PV panels can run an immersion heater to give you free or significantly reduced hot water in addition to lowering your electricity bills. A solar power diverter tracks the electricity you produce and can direct your excess energy toward warming your hot water tank.

Which Strategy Will Maximize the Return?

You shouldn’t just boost the quantity of electricity you use for show, you ought to utilize the same amount, but change how you use it to ensure you use it during the time of day when the sun sparkles at the highest.

You can alter your behaviour to use more electricity throughout the day. You could program your washing machine to start as soon as you leave for work. This implies that they operate when your photovoltaic PV panels’ electricity generation is at its highest.

Similarly, if your home has a hot water tank, connecting rooftop solar panels to an immersion heater is a great way to maximize your electricity usage. sadly, if you have a combi boiler, this won’t work for you.

How to Link Solar PV Optimizers with Immersion Heaters?

A sensor that is capable of determining in real time if electricity is being utilized is clipped onto electrical cables in every solar PV optimizer. It switches power to the immersion heater for heating the water as soon as it notices that electricity is being exported.

This technology enables you to use any excess energy you generate throughout the day to heat water using the immersion heater, making it ideal if you generate your electricity. Use this technology also to produce electricity through wind and hydroelectric power plants.

It’s a simple remedy because it can be used with your current immersion system and doesn’t need any additional equipment to function. As a result, you won’t need to use natural gas for boiling water.

Can Solar Panels Directly Heat Water with a 12v Immersion Heater?

Yes, a solar panel can directly heat a 12v immersion heater but choosing the appropriate panel is challenging. If you use an open connection with no regulator, a panel that is too large could burn out the element, and one that is too small won’t work.

Due to their high internal resistance, solar cells’ output voltage is greatly influenced by the current they are drawing. It also depends on how much sun there is. If you have a 100W panel with a 19V open circuit, it may gracefully drop to 12V under carry-on a 70W heater in direct sunlight.

Electrically heating even, a small amount of water is usually somewhat expensive. Only 20% of the incident solar energy is captured by PV solar panels, which then transform it into electricity. The immersion heaters are multi-kilowatt rated, so you’d need a sizable area of solar panels—say, 10 m2—to do this.

Savings Via a Solar-Powered Immersion Heater

Another option is installing a solar-powered storage system, also referred to as a solar battery. The battery stores excess solar energy so that you can use it later, when the photovoltaic cells aren’t producing energy, like at night or on a day with a lot of clouds, rather than diverting it to your immersion heater.

The Energy Saving Trust, a charity, estimates that the average price of electricity in the UK is roughly 13.33p/ kWh. This means that to run a 3kW immersion heating system for an hour would cost about 40p.

Size of an Immersion Heater Running Cost/ Hour Running Cost/ Week (2 hours a day) Running Cost/ Month (2 hours a day over 28 days) Running Cost/ Year (2 hours a day over 52 weeks)
3kW 0.50$ 6.96$ 27.83$ 361.76$
6kW 0.99$ 13.91$ 55.66$ 723.52$

Using standard electricity to power an immersion heater entails significant costs. A number of the power diverters on shelves have user-friendly displays that show you when the solar power is being diverted to the immersion heater and the amount of energy you are saving.

The Benefits of Heating Water with Solar Energy

An immersion diverter is installed separately from the solar panel as a smart add-on device. It enables you to boil your water using renewable energy sources for free, lowering the environmental impact and energy costs. The followings are some other advantages of heating water with solar power.

  • Immersion Diverters typically pay for their participation for just 2 years, making them an immediate return on investment. It will begin diverting the extra energy when your immersion diverter is connected to your solar PV system.
  • You can use all of your solar generations if you have an immersion diverter installed, so there won’t be any wasted green energy. It only takes 30 minutes to install a solar power diverter!
  • Solar PV combined with an immersion diverter is a less expensive, more upkeep-free alternative to Solar Thermal, so regardless of how much you send back to the grid or are using to heat your boiling water, you continue to make the same.

Besides, your Feed-In-Tariff transactions won’t change if you install an immersion diverter. This is due to not knowing exactly how much power you are exporting, the Feed-In-Tariff is going to reimburse for 50% of the electrical power you generate.


The free energy produced by solar thermal provides the homeowner with between 40-70% of their hot water. So, the immersion heater in your hot water cylinder must provide the remaining amount of heat.

Employing Solar PV System for heating water is a trustworthy choice because it has no moving pieces and is an inexpensive add-on. Installing a solar hot water system is a good way to reduce your energy costs and carbon emissions as you’ll use a standard heating system, and less of your supplier’s gas, oil etc.