There are quite a few different ways to save money with different solar systems.

Here are some of the most effective ways to save money with solar water heating systems:

What Is Solar Water Heating?

Solar water heating systems use the energy of the sun to heat water. This energy is completely carbon-free.

Water is heated using solar energy (sun rays). Water may readily be heated to temperatures of 60-80o C with minimal effort.

Related: Solar Thermal Technology (EXPLAINED)

How Does a Solar Water Heating System Work?

Solar water heaters are of two types:

  • Active.
  • Passive.


An active solar water heater uses pumps to circulate the water from the collector to the tank while a passive one uses gravity and thermosiphon principles for circulating water.

In an active system, a pump is used to circulate the water whereas, in a passive system, no pump is used.


In a passive system, water circulates naturally. The thermosiphon principle is used in a passive solar water heater. Warm water rises and cold water sinks.

When the sun heats the water in the collector, it becomes lighter and starts rising. This causes cold water from the bottom of the tank to sink and flow into the collector.

When the temperature of the water falls below 60°F, an immersion heater or a boiler may be utilized as an alternative to improve it.

Solar thermal collectors come in two varieties, both of which have a similar efficiency:

  1. Flat plate collectors
  2. Evacuated tubes

Flat plate collectors

A roof-mounted flat plate collector consists of hot water solar panels with a flat glass that is installed on the roof, whereas an evacuated tube system comprises several “vacuum tubes” connected into a manifold mounted on the top of a building.

Evacuated tubes

Aside from the collector, you’ll need to route insulated pipes from collectors to a hot water cylinder (either old or new).

The cold water in this cylinder is pumped upward through the collector, which heats it and then sends it to the top of the hot water store.

Related: The Different Types Of Solar Thermal Panel Collectors

Solar PV

Using your solar PV system to heat water is a long-term solution since there are no moving parts and an immersion diverter is an inexpensive upgrade.

Solar PV produces DC electricity, this is then converted to AC by an inverter. The generated AC current powers an immersion element in your hot water tank, heating the water.

The average 3-4 bedroom house can generate enough electricity during the day to power an immersion heater for 4-5 hours a night, providing around 50-60% of a household’s hot water requirements.

Solar PV is a great complement to solar thermal, providing a backup during extended cloudy periods and reducing your reliance on the grid even further!

Solar Water Heating and Heat Pumps

Combining a heat pump heating system with solar panels helps to ensure that your heating and hot water demands are met while being ecologically responsible.

Depending on the size of the solar array, it’s conceivable that solar panels would be able to meet all of your heat pump’s electricity needs.

So, by combining solar water heating with a heat pump, you are using renewable energy to power your home, which in turn reduces your reliance on fossil fuels and helps to combat climate change.

How Much Does Solar Water Heating Cost?

A domestic system will cost between £3,000 and £5,000, depending on the size of the property and whether you need a new hot water cylinder or use the existing one.

However, keep in mind that determining solar water heating panel prices is difficult; therefore it’s always a good idea to seek professional assistance.

When compared to a gas or electric immersion heating system, typical savings on a solar water heating system with an appropriately insulated building, proper installation, and efficient operation can be up to £60 per year when switching from a gas heating system and £70 per year when switching from an electric immersion heater.

Is There Financial Support Available?

Under The Smart Export Guarantee, you may be eligible to receive payments for the electricity your system exports to the grid. The payments are in addition to any bill savings you make.

The Smart Export Guarantee lasts for 20 years, and there is no upper limit on the size of the system that can apply – provided it meets the criteria and is accredited by Ofgem.

The most competitive Smart Export Guarantee contract is Octopus’s 7.5p per kWh premium, while the typical rate paid for electricity is now 28.3p per kWh.


How much will I save if I install a solar hot water heater?

Expect to save around 50-80% by installing a solar water heater. That means if your heat cost is £600 per year, you could save between £300 and £480 by purchasing a solar water heater.

How long does a solar hot water heater last?

Solar water heaters typically last for 20 to 30 years. However, the collector panels may need to be replaced after 10 to 20 years depending on the type of system.

Will passive solar still work if my home is shaded?

No, passive solar only works if the house or building receives direct sunlight. If your home is shaded, then you will not be able to take advantage of passive solar heating.

Do you need a water tank for solar panels?

Yes, you will need a water tank to store the hot water that is produced by your solar thermal system. However, it would need to be a new tank because the existing tanks are not designed to work with solar thermal systems.

About the Author

Passionate about helping households transition to sustainable energy with helpful information and resources.

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