Before you buy a solar water heating system, you must estimate how much hot water your household uses in a day, in a month and in a year, evaluate the capacities of the various systems and choose one that can fulfill the hot water needs of your home. Follow this handy checklist when shopping for a solar water heating system.
Step one – Choose an accredited supplier
Browse this website thoroughly or mail the DSM help desk at email@example.com for assistance and a full list of Eskom-accredited suppliers and products.
Request and evaluate quotations from at least three accredited suppliers.
Step two – Choose between a direct and an indirect system
Direct systems – water is heated-up directly.
Indirect systems – water is heated-up via a heat exchange mechanism.
- You live below the escarpment region and don’t get any frost.
- The water in your area does not have a high chemical content.
- You live above the escarpment region.
- Your area is prone to frost.
- The water in your area has a high mineral content (hard water) where calcium build-up occurs (check your kettle for lime scale build-up).
Hint! Indirect systems are suitable for all areas and potable water types.
Step three – Select the size of your system
The size of the system you buy depends on your household’s heated water requirements. The system should be capable of meeting these requirements so that you don’t have to rely on electrical back-up.
- Allocate 50 litres of hot water per person in your household. For example: four people = 200 litres.
- Then add an extra 50 litres to cover general domestic hot water usage. For example: 200 litres + 50 litres = 250 litres.
- Use this total as the minimum holding capacity of your solar water heater.
Hint! Consider the climate you live in when choosing your system. If you live in an area that gets a lot of rain or cloud cover, a lower cost system with smaller-size panels won’t meet your household’s hot water needs and the electrical element will kick-in to provide for the shortfall so you won’t save much electricity. Likewise, if you live in an area that gets lots of sunshine every day, a big system with big panels will produce more hot water than you need. This can cause the system to produce water that is too hot, which could be a safety risk.
Step four – Choose your storage
Pumped storage – water is forcibly moved by a pump.
Thermosyphon – the tank is placed above the panel, usually on the roof, and water moves by natural convection.
- You want the tank to be located away from the panel and hidden from view in a cupboard or in the ceiling. There are various pumps available, including renewable alternatives which use photovoltaic technology.
- You don’t mind having the tank in view on the roof.
- Your roof structure can handle the weight of the tank.
- You want to reduce the chance of insurance damage due to a burst geyser.
Step five – Choose your tank configuration
Standard installation – a new solar tank using a standard configuration.
Pre-feed installation – a solar tank and panels are fitted to an existing electrical geyser.
Retrofit system – solar panels are fitted on an existing electrical geyser.
- You want to replace your existing electric geyser.
- You want to optimise the use of solar energy rather than relying on electrical backup.
- You want to elicit the most electricity savings.
- You want to feed solar-heated water into an existing electrical tank. This type of installation is only recommended when extra hot water capacity is required.
- You want to save on the cost of buying a new solar tank. Your existing tank must be suitable for this type of application. It must also be in good condition. Your supplier can advise on the suitability of your tank.
Hint! A standard installation is the most common and recommended installation.
Step six – Claiming your rebate
- Ask your accredited supplier for your claim form. The form should have the details of the electrician and installer already filled-in.
- Complete your details.
- Attach the required documents. These include the original invoice, a copy of your ID and a copy of your utility bill as proof of residence.
- Post your claim to the facilitating auditors, Deloitte, within six months of the installation. Use the self-addressed envelope provided with your claim form or drop off your form in a designated drop box.
- You will then receive an SMS notification when the auditors receive your application, when your application is processed and queued for electronic payment or if your application is incomplete. Payment of the rebate is made within eight weeks from date of receipt.
Our Eskom-accredited suppliers can guide you through the process of selecting the right system for your needs.