General

Choosing the right solar heating system for your home

A consumer that wants to invest in a home solar water heating system should be careful to choose a system that is able to withstand the weather conditions in the area where he or she lives.

That’s the word from Graham Mundy, founder and managing director at Solar Beam, a pioneer of South Africa’s solar water heating solutions market. He says that most consumers are unaware of the differences between ‘indirect’ and ‘direct’ solar heating systems, with the result that many are duped into buying the wrong system for their homes.

Mundy says that consumers who live in a part of the country where the outside temperature drops to three degrees Celsius or less at any time of the year must install indirect solar water heating systems in their home.

An indirect system has been protected from freeze damage by an anti-freeze solution in the solar panels and a heat exchanger in the solar geyser.  The sun heats the anti-freeze solution in the panels and the heat exchanger transfers that heat into the water of the solar geyser.  This will ensure that the panels don’t freeze up and burst during winter.

People who live in areas where there is no frost and where it never drops below three degrees can fit direct solar water heating systems in their homes. In direct systems, water is heated in the solar panels and rises directly into the solar geyser.  These systems are slightly more efficient than the indirect systems.

Mundy says that the solar water heating solutions market is rife with confusion because a number of businesses have moved into this market to take advantage of its growth. Consumer interest in solar water heating has soared as a result of climbing electricity prices and a rebate Eskom is offering to homes that buy solar systems. Where there were once only nine companies supplying solar water heating solutions in South Africa, there are now more than 400, many of them opportunists without the experience or technology needed to provide a sound solution to business and residential customers.

“Don’t be misled by a slick salesman or a company’s well-known brand,” Mundy advises. “Instead, ask your proposed supplier how long the product has been active in the solar water heating solutions market. Many established companies with high-profile brands are only now joining the solar heating industry without the core competencies needed in the solar field. Sadly the consumer is paying the price for the proliferation of suppliers who lack the necessary experience. ”

Make sure that the company you choose has been in business longer than its guarantee and ask for references, preferably from a client who has had a system for five years or more.  Also ensure that your solar system of choice has the full SABS Mark of Approval. Do not confuse this baseline requirement with an SABS Compliancy Certificate, which is a once-off test on one item and does not guarantee continued quality.
The Compliancy Certificate is merely the first step towards becoming SABS Mark Approved. Also check that the SABS Mark of Approval applies to the entire system and not just to one or two components, says Mundy. “All too often, we see companies claim that they have the SABS Mark when they are using a solar geyser with the Mark and fitting it with a non-approved solar panel,” he adds.

Mundy says that consumers should be also wary of imported products, however good their credentials and certifications sound. “Foreign accolades are often meaningless in our harsh South African conditions,” says Mundy.

Many companies are trying to sell solutions based on glass tubes into the market, which are a poor fit with local conditions. Flat-plate technology is a better fit for South African weather conditions, says Mundy.

Mundy also cautions consumers against ‘retrofitted’ solutions, where a solar panel is simply connected to an electric geyser. The quality and performance of a retrofitted solution will not be up to the level offered by a dedicated solar system.

“The cost-savings of this approach might look attractive, but these solutions deliver disappointing results,” says Mundy. “One of the many reasons is that an electric geyser will cycle its contents electrically in around three hours, while a solar geyser needs to store 24 hours of hot water for the whole family’s daily needs.  This water will be heated by the sun over a six hour period.  That means the solar geyser must be bigger and have better insulation than your existing geyser.”

Concludes Mundy: “With the ongoing electricity supply crisis in South Africa, we all have a part to play in conserving energy. Installing a good solar heating system is an excellent way to conserve energy. But it’s important to do your homework so that you choose a solar heating system that gives you ample hot water and that will last you decades.”