Gas geyser installation in Cape Town is mostly a sizing exercise. Get the litres-per-minute rating wrong and you have bought a unit that goes cold whenever two taps run, which no amount of good installation work will fix.
This page covers sizing, where the unit can mount, what the installation involves, what it costs, and what to check before you buy the geyser rather than after.
Tell us how many bathrooms and whether the kitchen tap runs at the same time.
Get Gas Geyser Installation QuotesSizing a Gas Water Heater
Gas geysers are rated in litres per minute of temperature-raised water, not in storage volume. The number you need is set by how many outlets might run simultaneously, and by how cold the incoming water is, which in Cape Town in July is a lot colder than in February.
| Rating | Realistically supports | Suits |
|---|---|---|
| 8 – 10L/min | One outlet at a time | A flat, a cottage, a single shower |
| 12L/min | One shower comfortably, kitchen tap at a push | Small home, one bathroom |
| 16L/min | A shower plus a basin, or a bath | The common family-home size |
| 20L/min | Two showers, or a bath plus kitchen | Three or more bathrooms |
| 26L/min+ | Multiple simultaneous outlets | Guest houses, large homes |
Winter is the design case. A unit that copes in summer at 12L/min can disappoint in July, when the inlet water is far colder and the burner has more work to do for the same outlet temperature. Size up rather than down if you are between two options.
Where the Unit Can Mount
- Outdoor units mount on an external wall and are the simplest option: no flue and straightforward ventilation. Weather and, on the coast, salt are the trade-off.
- Indoor units need a correctly installed flue to outside and adequate room ventilation. More work, better protected, and the only option where there is no suitable external wall.
- Distance to the outlets matters. Every metre of pipe between the geyser and the shower is water you run off before it gets hot. Mounting it on the wall nearest the bathrooms beats mounting it wherever the gas already is.
- The cylinder position constrains everything. A geyser is a heavy gas load, so it needs to be reachable by a properly sized line from a cylinder position that is itself compliant.
What the Installation Involves
- Water demand assessed and the unit sized, ideally before you buy anything
- Mounting position agreed against water routes, gas routes and ventilation
- Cylinder capacity checked or upgraded, usually to a 48kg pair on changeover
- Gas line run and sized for the geyser's peak draw plus anything else on the system
- Cold feed and hot outlet plumbed in, and existing hot water re-routed if replacing electric
- Flue fitted and terminated correctly for an indoor unit
- Pressure test, commissioning, temperature set, and the certificate of conformity issued
Gas Geyser Installation Cost
| Item | Indicative range | Notes |
|---|---|---|
| 12L unit supplied | R3,500 – R7,000 | Entry to mid brands |
| 16L unit supplied | R5,500 – R11,000 | The common size |
| 20L+ unit supplied | R9,000 – R18,000 | Larger homes |
| Installation, outdoor mount | R3,800 – R7,000 | Gas and water connections |
| Installation, indoor with flue | R5,500 – R9,500 | Flue and ventilation included |
| Cylinder pair and changeover | R5,000 – R10,500 | Where none exists |
| Replacing an electric geyser | R8,500 – R20,000 | Including plumbing re-route |
| Certificate of conformity | R950 – R2,200 | Often included, confirm it |
| Total, supplied and installed | R9,000 – R22,000 | Unit and installation together |
Indicative ranges, not quotations. The cylinder position, the distance to the bathrooms and whether an existing electric geyser has to be decommissioned are what move the number.
Get quotes on the unit and the installation together so you can see the real total.
Compare Gas Geyser QuotesMultiple Outlets and Recirculation
Two bathrooms at opposite ends of a house on one geyser is the arrangement that disappoints people most. The unit may be big enough, but the far bathroom runs cold water for thirty seconds before anything arrives. Options are a second geyser near the far outlets, or a recirculation loop with a pump, which costs more and adds a small standing gas load. Worth raising with the installer at quote stage rather than discovering it afterwards.
Compliance and Servicing
The installation needs a certificate of conformity on completion, and a new one whenever the geyser is replaced or moved. Gas geysers also need routine servicing to keep the heat exchanger and burner clear, particularly in Cape Town's harder-water suburbs, which is covered on Gas Geyser Servicing Cape Town.
Frequently Asked Questions
What size gas geyser do I need?
One bathroom is comfortable on 12L/min, a family home with a bathroom and an en suite on 16L/min, and three or more bathrooms on 20L/min or larger. Size against simultaneous outlets in winter rather than average summer use.
What affects gas geyser installation cost?
The mounting position, whether the unit is indoors and needs a flue, the distance from the cylinder, whether cylinder capacity has to be upgraded, and whether existing hot water plumbing has to be re-routed from a decommissioned electric geyser.
How much does a gas geyser cost installed in Cape Town?
Supplied and installed, commonly R9,000 to R22,000 depending on the unit size and the installation. Installation alone, with the unit bought separately, typically runs R3,800 to R8,500 outdoors and R5,500 to R9,500 indoors with a flue.
Can a gas geyser be installed indoors?
Yes, with a correctly installed flue discharging outside and adequate room ventilation. It costs more than an external mount and is the right answer where there is no suitable outside wall or where coastal exposure would shorten the unit's life.
Can a gas geyser replace an electric geyser?
Yes, and it is a common Cape Town conversion. The electric unit is isolated and usually removed, and the hot water plumbing is re-routed to the new gas unit. Budget R8,500 to R20,000 including the plumbing work.
How much gas does a geyser use?
Considerably more than a hob. A household with a 16L/min geyser and a hob commonly runs through a 48kg cylinder in four to ten weeks, faster in winter. Two cylinders on automatic changeover is the sensible arrangement.
Does a gas geyser work during load shedding?
Fully electronic-ignition units need power for the control board. Battery-ignition models do not. If uninterrupted hot water during outages is the reason you are switching, confirm which ignition type the model uses before buying it.
Gas geyser quotes, unit and installation, are compared through Gas Installers Cape Town at no cost.
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