Solar geysers vs heat pumps: what's best?

23 Aug 2017

With the latest tariff hikes placing more pressure on consumers, it is becoming increasingly important to find alternatives for the largest energy-consuming appliances in the home.

This is according to Cala van der Westhuizen, Head of Marketing and Sales at Energy Partners Home Solutions, who says water heating accounts for as much as 50% of a household’s electricity use.

He says replacing a home’s conventional geyser with a renewable energy alternative is one of the first steps to drastically reduce an average home’s monthly electricity spend. He says the current renewable energy powered water heating options available to homeowners are heat pumps and solar water heaters.

He says a heat pump uses energy from the surrounding air to heat water, while a solar water heater relies on the sun for power. Cala says both of these options are a good energy-smart investment, but each holds different advantages and disadvantages.

Understanding the major differences between the two systems will help you choose a system that’s right for you and your family.

Solar Geysers:

A solar water heater is much easier to install than a heat pump, and the total cost of an average 200l system is around R26 000.
In the short-term, this is cheaper than an average heat pump with a 300l efficient tank system, which costs around R35 500.

Solar water heating systems can also be expected to last for over ten years, while heat pumps generally need to be replaced after five to ten years.

Despite initial upfront costs, heat pump systems have significant advantages over solar heating.

A solar panel needs to be oriented towards the sun to operate at maximum efficiency, and when there is no direct sunlight on the system, like at night or on an overcast day, the system relies on a regular geyser element.

As a result, the efficiency of a solar heating system fluctuates between 45% and 70%. This comes down to an average drop in energy costs by approximately 54% over the course of one year.

Heat pumps:

In contrast, a heat pump system is only slightly affected by variations in temperature, and therefore it runs efficiently at any time of day.

It requires approximately one-third of the energy of a conventional geyser to heat the same amount of water, resulting in an average energy saving of up to 70%.

This results in a cumulative cost saving of around R62 500 for a standard four member household using an average of 52l of warm water per person over a 10-year period.

By comparison, a solar heating system achieves around R59 500 in savings under the same conditions.

Cala recommends homeowners from Gauteng and the Western Cape install heat pumps as they are more efficient than electric geysers and lead to bigger electricity savings over the long term than a solar water heater.

Both Gauteng and the Western Cape receive less sunlight during their respective rain seasons, which means that a solar geyser will use a lot more electricity from the national grid.

Heat pumps are consistent, rely on air and can cut the cost of water heating by more than any other system currently on the market.