Pick the geyser that fits your house, not just your budget

Gas, solar or electric geyser: which suits your home comes down to your roof, your household and your access, not the winner on paper. No guessing, just what fits your place. This is for older far-south homes.

By Zaid Petersen, Owner and master plumber

Published 14 November 2026

What actually decides which geyser type suits your house

Four things decide it: how many people shower, your roof space, whether you have gas or electricity access and your budget. Not which type sounds best online. A guide that names one winner for every house is guessing about yours.

Start with the showers. A couple in a Fish Hoek cottage who each shower once a day has a different demand from a full house with three teenagers. That daily demand sets the tank size and the tank size sets everything after it. A 150 litre tank suits a small household. Push past four heavy users and you are looking at 200 litres or more.

Then the roof. Solar of any kind needs unshaded roof facing the sun. Plenty of older Muizenberg and Kalk Bay homes have a small roof, a north face blocked by a neighbour or a big oak. Gas needs a wall for the unit and safe ventilation. Electric needs the least: a spot for the tank and a working supply. Match the type to what your house actually gives you.

Budget lands last, on purpose. The cheapest geyser to buy is often the dearest to run. The priciest to install can pay itself back over years. Weigh the buy price and the running cost together. Sorting your household size and roof first is the easy part. What trips most people up is the word solar, because it hides two very different machines.

Solar thermal and PV electric geysers are not the same thing

Two machines share one name and that name costs people money. Solar thermal heats your water straight from the sun. PV makes electricity from panels and feeds a normal element. Knowing which one you are being quoted on changes the whole decision.

A thermal system runs water through panels or tubes on the roof and the sun warms it as it passes. Fewer moving parts and it is efficient at making hot water. The catch is the roof. The tank often sits up there too, so the structure has to carry the weight.

PV works the other way. Panels make electricity and that power heats the element in a standard tank inside. It is the same idea as running your house off panels, pointed at your hot water. People ask how many panels a 150 litre geyser needs. The honest answer is that it depends on the panel size, your sun and how much of the heating you want the sun to cover versus the grid. A plumber should size it for your roof, not read you a number off a chart.

Here is the practical split. Thermal is usually simpler and cheaper to get hot water alone. PV suits a home already going solar for the lights and plugs. Neither is the right answer for every house, which is the whole point. Once you know which machine you are actually looking at, the next question is what the City wants before it goes up on your roof or wall. For wider background, see Smart Living Audit Guide for Your Home (capetown.gov.za).

How Cape Town's rules affect your installation

Cape Town has its own steps for geyser work. Most national guides skip them entirely. New installs and replacements need to meet the City's requirements. A registered plumber has to sign off the geyser installation with a compliance certificate. Skip this and you can hit trouble at resale or with an insurance claim.

The sign-off matters most when something goes wrong later. Say your geyser bursts and floods the ceiling. Your insurer will often ask whether the install was compliant. A Certificate of Compliance from a registered plumber answers that question. That's the kind of registration this sign-off calls for.

Solar adds another layer. Panels on the roof touch the structure. PV that ties into your electrical supply brings its own electrical rules on top of the plumbing. Here the paper trail matters most. A proper install leaves you with the right certificate, not a promise. Ask any plumber whether the job comes with sign-off you can produce later.

None of this is meant to scare you off. The rules exist so the person on the far end, the insurer or the next buyer, can trust the work without standing in your roof. Nobody wants to guess about a job hidden in the ceiling. A clear certificate takes the guessing away.

Rule out a repair before you commit to a new geyser type

Check for a repair before you swap the whole geyser. Plenty of faults are a worn element, a failed thermostat or a leaking valve, not a dead tank. Swapping the whole geyser when a part would do is money down the drain.

The honest test is simple: what is actually broken? A geyser losing pressure or tripping the electricity often needs one part, not a full swap. A tank rusted through or pinholing from age is a different story. Patching that is throwing good money after bad. A plumber worth calling tells you which one you have before quoting a replacement. That is the difference between fixing your problem and selling you a new geyser.

We would rather talk you out of a job you do not need than fit hardware to make a bigger invoice. If a timer and a repair solve it, that is what we say. No guessing about what is wrong. No rushing to the next call. No inflated bill for work that never fixed the thing you phoned about. You get told what is broken and what it costs and the two match.

Work out your household size, your roof, your access and whether a repair beats a replacement. Then you can ask for a quote knowing the right question instead of the wrong assumption. If you want a plainer walk-through of the choice itself, choosing-a-geyser sets it out.

Frequently asked questions

How many solar panels do I need to run a 150 litre geyser?

The number depends on the panel size, how much sun your roof gets and how much of the heating you want the sun to cover versus the grid. Two roofs facing the same way in Kalk Bay can still need different setups because of shading, pitch and household use. The straight way to get a real number is to have a plumber look at your roof and size it for your house, not read a figure off a chart.

Will I get overcharged for something small, like a part on the geyser rather than a full swap?

A worn element, a failed thermostat or a leaking valve should be priced and quoted as what it is, not folded into a full replacement. The way to check is simple: ask what part is broken and get that written on the quote before any work starts. If the diagnosis stays vague and jumps straight to a new geyser, that is your cue to ask more questions.

Will the plumber rush the job because they're already thinking about the next one?

A rushed job usually shows up as a guess instead of a diagnosis, so watch for whether someone actually checks what is wrong before quoting. Ask what tests were done and what they found. A plumber who explains the fault in plain terms before moving to a fix is not rushing you.

Will the plumber actually turn up when they say they will?

There is no way to promise that from an article, but you can ask about it directly before booking. Ask how they handle delays and whether they will message you if something changes. A clear answer to that question tells you more than any promise on a website.

Could I end up with an inflated invoice for work that doesn't even fix the problem?

That risk drops when the invoice matches the quote and the quote matches a clear diagnosis, so ask for both before work starts. Get the fault named in writing, not just the fix. If the bill covers something other than what was agreed, that is worth raising before you pay it.

Will whoever comes out actually have the right tools and know-how to sort out my hot water problem?

You can check this before anyone arrives by asking what they think is wrong and how they plan to confirm it, since a clear answer tells you more than a van full of tools. Solar and gas installs bring extra rules on top of plumbing, so ask whether the person has handled that type of geyser before. A straight answer, not a vague one, is the sign to look for.

Explore more

• Choosing a geyser that fits your home, not just your budget

  Learn how size, type and running cost decide the right geyser for your house.

Ready When You Are

For more on this, see Choosing a geyser. If you would like to talk it through, get in touch.

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