Retrofit To Your Geyser
A collector added to the roof and plumbed to the geyser you already have, with a circulating pump and controller where the layout needs one.
Home/Solar Geyser Installation
Solar geyser installation in Bellville has to be planned around June, not January. Laid flat, a collector here gets under a third of its summer sun in midwinter, so it is faced north, tilted for winter and given a backup timer that leaves the sun its share.
Keeping the current geyser and adding solar, or starting fresh? Mention the direction your roof slopes as well.
In Cape Town "solar geyser" covers two technologies. One heats the water with the sun directly, the other makes electricity for the element. Both need the same care on the water side.
A collector added to the roof and plumbed to the geyser you already have, with a circulating pump and controller where the layout needs one.
A new tank and collector as one system, either close-coupled on the roof or with the tank kept in the roof space below the collector.
Photovoltaic panels feeding the geyser element through a controller. The City must authorise the system, and a registered electrician certifies the wiring.
High-pressure tanks get pressure control, relief valves and vacuum breakers like any geyser. Low-pressure systems are fed at the pressure they are built for.
Flow and return pipes between the collector and the tank lagged along their full length. Heat lost on the roof is heat the sun collected for nothing.
The backup element set to run only when the sun has not done the job, at the times the household actually draws hot water.
Over a whole year, a square metre of ground in Bellville receives about as much sunshine as one in Johannesburg: close to 2,000 kWh in both, on the European Commission's PVGIS satellite record for 2014 to 2023. The difference is when it arrives. Cape Town gets its rain in winter, under a low sun, while Johannesburg's winter is its dry season.
On a flat surface in Bellville, an average June day delivers about 2.5 kWh per square metre, against about 8.5 in January. That is under a third. In Johannesburg the June figure is about 4.0. So a solar geyser here does its least work in the months when the water coming into the house is coldest, and the backup element is left to make up the difference.
Tilt is the part an installation can control. Faced north at the 31 degrees PVGIS rates best across a full year, a collector in Bellville gathers about 4.0 kWh per square metre on a June day. Raised to 45 degrees, it gathers about 4.4, and gives up only about 2.5% of the year's total, nearly all of it in summer, when the collector has sun to spare.
So the installation is set out for winter. The collector faces north, on a frame where the roof does not, and is tilted steeper than a shallow roof would hold it. The tank and collector are sized against a June day rather than a January one, and the backup element goes on a timer or controller that tops the water up after the sun has had its turn, instead of heating a full tank at dawn and leaving the collector little to do.
Before you sign for a solar geyser, ask for two settings in writing: the angle the collector will sit at, and when the backup element is set to switch on. In Bellville those two decide how much of your winter hot water the sun actually pays for.
A solar geyser puts a pressure vessel, hot pipework and roof fixings on your house at once. Each gets the same attention.
The collector's direction and tilt are chosen for June output and written on the quote.
Every roof fixing and pipe entry is sealed, so the hot water does not come with a ceiling leak.
The tank gets the same pressure control and relief protection as any geyser fitted here.
The City notified, the plumbing certificate issued, the electrician's certificate where PV is wired in, and the warranty registered.
Three things set most of the price: whether the existing geyser is converted or a complete system is installed, the size of the tank and collector, and how the roof is reached and fixed to. A PV kit adds panels, a controller and an electrician's certificate. Each part is listed in the quote before work starts, as described on the plumber prices page. The City said in May 2024 that no subsidy was available for solar water heaters, and the Eskom rebate ended in April 2015.
On sunshine across the year, yes: Bellville receives about as much as Johannesburg. The weak months are June and July, when a flat collector gets under a third of its January sun. Tilting it north at around 45 degrees keeps far more of the winter sun, and the backup element covers the rest.
Usually, if the geyser is sound and has years left in it. A retrofit adds the collector, the pipe runs and the controls, and keeps the tank you already paid for. A geyser near the end of its life is better replaced with a complete system than converted now and replaced a year later.
A solar geyser heats water directly: the sun warms water or fluid in a collector on the roof, and that heat goes into the tank. A PV geyser uses photovoltaic panels to make electricity for the geyser element. In Cape Town a PV geyser counts as small-scale embedded generation, so the City must authorise it even when it is not connected to the grid, its geyser switch must be a model on the City's approved list, and a registered electrician issues the certificate for the wiring.
Several rules apply. Solar hot water panels are on the Water By-law's list of components an owner reports to the City once fitted or altered, and the work has to meet SANS 10106. The national building regulations class a roof-mounted solar water heater of up to 6 m² as minor building work, and the City's zoning scheme keeps rooftop geysers and solar panels within 1.5 m of the roof surface. A PV geyser needs the City's authorisation as well. Older buildings and heritage overlay zones can need further approval, so the property is checked before anything goes on the roof.
Both work here. Evacuated tubes are insulated by a vacuum, so they lose less of their heat on cold, windy or overcast days, which is when a Cape Town system is under most pressure. Flat plates are a simpler, robust panel. The choice also depends on the roof, the tank and whether the system is high or low pressure.
Usually. A frame can turn the collector to face north on most roof shapes, and on a flat roof it sets the winter angle as well. Shade is the harder limit: a collector shaded by a neighbouring roof, a tree or a parapet in the winter months loses the sun it needs most.
Not always. When the tank sits above the collector, as on a close-coupled roof system, heated water rises into the tank on its own. When the tank is lower down, a small pump and controller move the water between the two, and they need power to run.
Get In Touch
Thinking about solar for the geyser? Tell us the size of your current geyser and which way the roof faces, and we will come back with the options.