Solar geysers: An upward trend

A good overview of solar geysers

Solar geysers are rapidly increasing in popularity. Drive past any new housing development and one will see geysers propped up all over roof tops. Technically, people have used solar energy to heat water for centuries. However, solar geysers have only become mass produced and commercially viable in the past few decades.

A geyser is essential to any home, which is only logical. You use hot water every day to bath or shower, do the laundry, clean the home or wash the dishes. Solar geysers are a forward-thinking, modern alternative to conventional water heating systems, including tankless coil geysers, gas geysers, electric geysers, or heat pump geysers, all of which use either gas, oil, or electricity as their energy source.

A solar hot water system uses the sun’s energy to generate warm water for your home. This approach will help you to save money and reduce your reliance on electricity. It will also reduce your carbon emissions.

Solar geysers

How a solar water heating system works – the basics

Solar geyser systems capture thermal energy from the sun and use it to heat the water needed for your home. These systems include a few key components: collectors, a storage tank, a heat exchanger, a controller system as well as a backup heater.


The panels in a solar water heating system are known as “collectors,” and are typically installed on a rooftop. These collectors differ from the photovoltaic solar panels most people familiar with. Instead of generating electricity, they generate heat. Solar radiation passes through the collector’s glass covering and strikes a component referred to as an absorber plate. This plate has a layer of coating designed to capture solar energy and convert it to heat. This generated heat is transferred to a “transfer fluid” (either potable water or antifreeze) contained in small pipes in the plate.

Solar geysers

Heat exchanger and storage tank

Once the transfer fluid in your collectors has been heated up, it moves into a set of pipes known as a heat exchanger. This exchanger is located inside the storage tank for your hot water. When these pipes are filled with heated transfer fluid, the heat is transferred from the pipes to your water. In this way, the water is heated and ready to be used in your home.

Controller system

Most solar geysers have a protective controller system that ensures the water in the storage tank does not get too hot. Controller systems can also prevent cold water from being cycled through the system if it gets extremely cold outside and the transfer fluid isn’t being warmed sufficiently.

Backup heater

Lastly, solar water heating systems usually come accompanied by a backup system. On days when it is too cloudy to generate sufficient hot water from solar energy, the backup heater will kick in and generate hot water for your home using electricity.

Solar geyser types – Direct vs. indirect and active vs. passive

Every solar hot water system is made up of the same basic parts, but there are a few differences in system design. The differentiator of direct or indirect system, impacts how the fluid is heated in the collectors. One must also choose between an active or passive solar hot water system, which impacts the way that fluid moves through your system.

The key difference between direct and indirect solar hot water is the type of fluid used to collect heat in the system. In an indirect system, solar energy is collected and held in a special antifreeze fluid. The antifreeze is circulated into your hot water storage tank, which heats water for use in your home. However, in a direct setup, your water gets heat directly from the sun, rather than being collected in a transfer fluid first.

Indirect systems are more resistant to cold temperatures, and are better at retaining heat energy during colder winter months. However, indirect systems tend to also be more expensive than direct systems. Moreover, direct solar hot water systems tend to work better in countries or areas with warmer climates.

In a solar water heating installation, antifreeze fluid or water is moved throughout the system with a controller pump or with gravity. Controller pumps are only used in active solar hot water installations. Passive systems rely on gravity to move fluid and water around.

While passive systems are less complicated to install, they tend to be less efficient than active systems. Additionally, some passive systems need to have their storage tank installed higher up than the collectors to work, which can place strain on your roof.