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Evacuated Tube

Solar Geysers – Everything you need to know

Today you’re going to learn everything about Solar Geysers and Solar Geyser Installation types.

We will go through the various options, how they work and what they cost. It’s a guide that will help you choose the right one for your home.

Let’s get started.

Chapter 1

What Are Solar Geysers

Let’s start from the top

The main components of a Solar Geyser comprise of a water storage tank and the Solar Collector.

There are two functional variations of a Solar Geyser, the first heats water directly and the second uses a heating liquid which mixes water and glycol.

What Are Solar Geysers
Chapter 2

The Major Types Of Solar Geysers Available

Let’s start from the top

To find the right type of Solar Geyser for you it’s best to understand the different options, here are the main types available, how they work and their Pros and Cons.

Types Of Solar Geysers

Here Are Some Interesting Facts

  • The geyser is usually responsible for the majority of your electricity bill
  • Solar Geysers can effectively provide warm water for up to 15 years, if not longer
  • You are less dependent on the overall grid
  • The options you get with Solar Geyser collector kits ensure that there’s a package that fits your budget
  • You can make your money back on the investment within 2 years
  • You save thousands over the course of several years
  • The maintenance required for a Solar Geyser is almost non-existent unless there are moving parts involved such as a pump
  • A Solar Geyser is just as capable of heating water up to 90 degrees
  • The solar geyser installation is quick and very straightforward

Flat Plate Collector

A Flat Plate Solar Geyser is perfect for our South African conditions.

How Does it work?

It does require direct sunlight, predominately North facing to heat the water and should be clear of all cast shadows from trees or buildings.

Although not as efficient as the evacuated tube system, this is far effective enough for our hot conditions.

  • North Facing
  • Requires direct sunlight
Flat Plate

Evacuated Tube Solar Collector

Evacuated tube collectors are the most efficient collectors on the market.

How Does it work?

Originally it was designed for European conditions where sunlight is scarce and the temperatures are much colder. This collector system uses UV rays and not direct sunlight.

With this, it also has heating rods that amplify the heating process to achieve higher temperatures than that of the flat plate collectors. Being that our conditions are extremely hot in South Africa, the use of evacuated tubes are recommended to be used in the following conditions to avoid overheating and wasting of water due to vacuum release.

  • East / West facing roof
  • Partially shaded placement of collector
  • Freezing conditions
  • Most efficient

Pumped Solar Geyser System (Retrofit)

A pumped system commonly known as a “Retrofit” is used when the storage tank or electric geyser is used and is below the position of the collector.

How Does it work?

Water from the geyser is needed to be re-heated and is required to be pumped up into the collector and back down once heated into the geyser.

Although more parts involved make this a higher maintenance option due to there being moving parts, it is also a cost-effective route as well as less of an eyesore due to the tank not being visible on the roof.

  • Cost-effective
  • More discrete than a Thermosiphon
  • Higher maintenance
Retrofit Solar Geyser Installation

Thermosiphon Solar Geysers

These Solar Geyser systems the most common and most reliable systems as there are very little parts involved along with the main process being a natural one.

How Does it work?

Cold water is pushed into the solar water collector and is then heated by the sun. Because heat rises and cold sinks, all the hot water is automatically pushed to the top of the collector and into the geyser that is placed above the collector.

When the water cools it pushes the cold water back down into the collector and re-heats. This process happens with no aid of any mechanical means.

  • Most reliable
  • Most common
  • Least moving parts

Direct Thermosiphon Solar Geysers

A Direct Thermosiphon Solar Geysers utilizes a standard thermosiphon geyser that doesn’t need to be protected in cold conditions.

How Does it work?

Although still made to withstand weathering in the outdoors, it does not offer any extra insulation for water storage.

  • Very good for coastal areas and areas that do not reach 0 degrees.

Indirect Thermosiphon Solar Geysers

An Indirect Thermosiphon Solar Geyser system is designed for areas situated in extremely cold conditions.

How Does it work?

Being that the geyser is on the roof, it is exposed to the open air and ice deposits from the temperature drops.

The indirect geyser has a jacketed layer around the cylinder that gets filled with glycol, an insulating liquid, that ensures the temperature of the water in the tank is kept from freezing or cooling too fast.

  • These systems are best for inland areas where it drops down to 0 degrees or below in winter.

Closed Coupled Solar Geysers

Closed coupled Solar Geysers are 1 piece systems.

How Does it work?

The tubes go directly into the tank utilizing sleeves to connect it. These are direct thermosiphon systems so are purely designed for areas that are not extremely cold in the winter time.

  • These systems are best for warmer areas where the temperature & doesn’t drop very much.
Closed Coupled Geyser

Low-Pressure Solar Geysers

Low-pressure Solar Geysers are closed coupled systems that transfer the hot water using gravity.

These systems are perfect for farm areas or areas where the temperature never really reaches below 15 degrees. Because the hot water is gravity fed, the cold water mixing usually makes it too cold to use, therefore only having very light shower conditions.

  • Only ideal for warmer areas
  • Low-pressure showers make it cold to use
Chapter 3

Solar Geyser Prices in South Africa

How Much Do They Cost

Solar Geysers have certainly gone down in price, due to new building regulations it is required that every new house built is required to have a Solar Geyser installed.

The low cost makes it so attractive in general but also saves a lot of money, you can pay as little as R3,323* for a 100L Low-pressure up to R19,441* for a top of the range 200L High-pressure Solar Geyser.

You can take a look at the full range here →
*Prices as of Nov 2018



  1. Visitor Rating: 4 Stars

  2. Anonymous

    Visitor Rating: 4 Stars

  3. Hi yes you can, these types are called Retrofits. The collector is mounted on the roof and connected to your existing geyser, it comes with a pump that circulates hot water into your geyser.

    We have a range of these here

  4. Visitor Rating: 4 Stars

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