Gas vs Solar vs Heat Pump Geysers- Prices and Savings Compared.

South African households who want to save money on water heating can replace their conventional electric geyser with a gas, solar, or integrated heat pump geyser.

Conventional electric geysers can make up between 40% and 60% of a household's monthly electricity usage.

Increasing the water temperature requires heating a conductive element, similar to the one in a kettle but significantly larger.

These elements' power consumption can vary between 1kW and 3.5kW. In many cases, the latter is preferred because it can heat water faster.

A household of four that needs to shower or bathe every day will require an electric geyser to heat their water tank multiple times during the day.

If 40% of the average South African household's 900kWh monthly electricity consumption goes towards geyser heating, the element will consume roughly 360kWh per month.

On a Block 2 tariff in the City of Tshwane, that works out to about R1,170 per month.

The power-saving trinity

Three types of geysers can help reduce this expenditure significantly.

The first option is a solar water geyser, which is highly popular in South Africa due to the country's abundance of sunshine.

There are two types of solar geyser configurations available - direct and indirect.

• Direct - Water moves through a solar collector and into the geyser's storage tank using electrical pumps and controls, or through natural thermosiphoning. This system is preferred in hotter areas without frost issues.
• Indirect - Uses a solar collector with a non-freezing heat transfer fluid. This fluid moves through a heat exchanger surrounded by water, which, in turn, heats up. This setup is preferred in frost-prone areas where the water could freeze and stop moving.

Many solar geysers also have elements that can tap into your electricity connection to top up when sunshine is insufficient, or the overall water temperature has declined below the set temperature due to consumption.

Gas geysers heat a radiator with a burning flame in an enclosure.

Water is pumped through this radiator and heated rapidly for consumption.

This system does not need a large storage tank, with capacities around a tenth of a typical geyser.

For larger households, a sub-20ℓ geyser might not be sufficient if multiple people want to shower or bath simultaneously.

While the geyser itself takes up less room than a conventional unit, you need space for the bottle that holds its gas.

The last option - an integrated heat pump geyser - still requires electricity as its primary heating source.

However, it consumes around 80% less electricity to heat water through reverse refrigeration.

Firstly, heat from the surrounding air is used to heat up a refrigerant in an evaporator chamber.

The refrigerant boils and vaporises before moving a the compressor, which increases the pressure and temperature before being pumped to the condenser using electricity.

The condenser chamber grabs the heat from the pressurised vapour in a heat exchanger and uses this to heat water.

The refrigerant condenses back into liquid and goes through an expansion valve where the temperature and pressure of the refrigerant are reduced, before moving back to the evaporator chamber.

We compared the upfront and running costs, features, benefits, and downsides of each type of geyser in the table below.