Solar PV has become a popular choice for South African homeowners looking to reduce their electricity costs. One of the biggest energy users in a home is the geyser, which naturally raises the question: should you use your solar panels to heat the geyser directly?

It sounds like a good idea. However, there is another option worth considering.

Combining a solar PV system with an efficient heat pump can make better use of your available roof space while still providing plenty of hot water for your home.

The problem with using PV to power a geyser element

A conventional geyser uses an electrical element to heat the water. If the element is rated at 3 kW, it uses electricity to produce heat at roughly a 1:1 ratio. In simple terms, one unit of electricity gives you approximately one unit of heat.

There is nothing wrong with this technology. It has been used successfully for many years.

The issue is what happens when the geyser reaches its required temperature.

The element switches off.

Your solar panels may still be producing electricity, particularly during the middle of the day when solar generation is at its highest. That electricity then needs to be used somewhere else in the house, stored in a battery, exported to the grid where possible, or potentially curtailed.

There is also the question of roof space. If a large portion of your solar PV system is being sized around the electricity needed to heat water, you may need more panels than you otherwise would.

A heat pump changes the equation

A heat pump works differently from a traditional geyser element.

A heat pump works a little differently from the element in a normal geyser. A heat pump doesn’t heat water in quite the same way as the element in a normal geyser. It takes heat from the air around the unit and moves that heat into the water. Electricity is still needed, but far less of it is required to produce the same amount of hot water.

For example, a heat pump with a COP of around 3.5 to 4 can deliver roughly 3.5 to 4 units of heat for every unit of electricity it uses. That’s a big difference when you compare it with a standard geyser element, where one unit of electricity gives you about one unit of heat.


Of course, the exact performance won’t always be the same. Things like the outside temperature, the temperature of the water and how the system has been installed all make a difference. Even so, the saving compared with a traditional geyser element can be significant.

Your solar power can be used throughout the home

This is where the combination of solar PV and a heat pump becomes particularly useful.

During the day, your solar panels produce electricity. If the water temperature has dropped, the heat pump can use some of that available electricity to heat the water.

Once the water reaches the required temperature, the heat pump stops.

The solar panels can then continue supplying electricity to the rest of the house.

Your refrigerator, washing machine, computers, lights and other appliances can all make use of the available solar energy. If you have batteries, they can also be charged.

Instead of dedicating a large amount of solar generation to a conventional heating element, the energy can be shared across the household.

Making better use of your roof

For many homeowners, roof space is limited. You want every solar panel to contribute as much as possible to reducing your reliance on grid electricity.

Using an efficient heat pump means you don’t necessarily need to generate as much electrical energy specifically for water heating.

This can be particularly helpful in designing a new solar installation. Instead of just adding more panels to a high demand geyser element, you can think about the total energy needs of the house and use a heat pump to reduce the amount of electricity needed to produce hot water.

A practical combination for South African homes

Solar PV and heat pumps work well together because they perform different jobs.

The solar panels generate electricity. The heat pump uses that electricity efficiently to produce hot water. When the hot water is ready, the heat pump switches off and the solar power becomes available for other household requirements.

It is a simple concept, but it can make a meaningful difference to how efficiently your solar system operates.

At SunScan, the focus is on helping homeowners find practical and energy-efficient solutions for hot water.  A heat pump, combined with correctly sized solar PV, can help you make better use of your available roof space while reducing the electricity required to heat your water.

The goal isn’t simply to install more panels.

It is to get more useful energy from the panels you already have

If you’ve already have a geyser at home and are thinking about solar, you might be wondering whether you have to replace the geyser as well.

In many cases, you don’t.

This is actually one of the first things worth checking before spending money on a completely new hot-water system. If the geyser is still in good condition, it may be possible to keep it and add a heat pump, solar thermal collector, or a combination of the two.

That can be a much more practical way of improving the system.

Adding a heat pump to an existing geyser

A heat pump can be used with an existing geyser in suitable installations. The geyser continues to hold the hot water, while the heat pump does the job of heating it.

The difference is in the way the water gets heated.

A heat pump works differently. It takes warmth from the air around the unit and uses it to heat the water. The electricity is mainly needed to run the heat pump and move that heat where it is needed.
The result is that you don’t need as much electricity to get the water up to temperature. That’s the main reason people look at heat pumps when they want to cut down on the cost of running their geyser.

And if your existing geyser is still in good shape, there’s no reason to throw it away just because you want to change the way you heat the water. In the right setup, the heat pump can work with the geyser you already have.

The existing tank may still have plenty of life left in it.

What happens if you already have solar?

Solar PV is slightly different because the panels produce electricity rather than hot water.

That electricity can be used anywhere in the house. You can run appliances with it, charge batteries and, of course, use it to run your hot-water system.

This is one reason solar PV and a heat pump make such a good combination.

During the day, your panels are producing electricity. If the water in the geyser needs heating, the heat pump can use some of that power. Once the water has reached the required temperature, the heat pump stops.

The solar panels don’t stop, though.

Whatever electricity is still being produced can go towards the rest of the house.

Can you have solar and a heat pump on the same geyser?

In a suitable installation, yes.

This is probably one of the better ways to get more out of an existing geyser.

The solar PV system supplies electricity, the heat pump uses that electricity efficiently to heat the water, and the existing geyser provides the storage.

There is no need for the heat pump to be running simply because the sun is shining. It runs when the water needs heating.

That point is worth considering when you’re looking at the size of a solar installation. If you use a conventional geyser element, a lot of electricity will be needed to heat the water. With a heat pump, much less electrical energy is required for the same job.

The difference can help you get more from the solar panels you already have.

Is every geyser suitable for a retrofit?

Not automatically.

The condition of the geyser is important. If the tank is old, leaking or already showing signs of trouble, putting additional equipment onto it may not be the best use of your money.

The size of the geyser needs to be considered too. A small household with relatively low hot-water use has different requirements from a large family.

Then there is the installation itself. The position of the geyser, available space for the heat pump, pipework and electrical supply all need to be checked.

It’s much better to look at these things before buying equipment than to discover afterwards that something needs to be changed.

Retrofitting can save you from replacing a perfectly good geyser

The idea behind a retrofit is fairly simple. If something you already own is still useful, why replace it unnecessarily?

A good existing geyser can potentially become the storage part of a more efficient hot-water system.

You can add a heat pump to reduce the electricity needed for heating, and solar PV can provide the electricity for the heat pump while also supplying the rest of the home.

For some households, installing both at the same time could make sense. For others, starting with a heat pump and adding solar later may be the better route.

There isn’t one answer for every house.

At SunScan, we can recommend an installer who can assess your existing geyser and look at what can realistically be added to it. The condition of the geyser, your hot-water requirements and the available space all form part of that decision.

So before you remove a geyser that is still working properly, have a look at the retrofit options first.

You may already have the most expensive part of the system sitting in your home. It might just need the right technology added to it.

If you’ve been looking at ways to keep your swimming pool warm, you’ve probably noticed there are two main types of heat pumps available. There are the older on/off models, and then there are inverter heat pumps, which have become increasingly popular.

On the surface, they do much the same job. Both take heat from the surrounding air and transfer it into your pool water. The real difference is in how they run, and that can make quite a difference to the amount of electricity you use.
The real difference is what happens inside the machine once it starts running.

That difference can have a noticeable effect on your electricity bill.

How does a standard pool heat pump work?

A traditional on/off heat pump is fairly straightforward.

With a standard on/off heat pump, things are pretty straightforward. When the pool gets too cold, the compressor kicks in and runs at full power. It stays that way until the water reaches the temperature you’ve set, then it switches off. Once the pool cools down again, the whole process starts over.. Then it switches off.

When the water cools down again, the compressor starts up and the process repeats.

There is nothing particularly wrong with this type of heat pump. It is a proven technology and usually costs less to buy. The drawback is that the compressor has only two settings: **full power or off**.

It cannot slow down when the pool is nearly at the temperature you want.

What does an inverter heat pump do differently?

An inverter heat pump is able to change the speed of its compressor according to what the pool actually needs.

When you first start heating a cold pool, the unit can work harder to get the temperature up. Once the pool gets close to the temperature you have selected, there is no reason for the heat pump to keep running flat out.

The inverter slows down.

This is where much of the energy saving comes from.

Instead of repeatedly switching between full power and completely off, the heat pump can settle into a lower output and maintain the pool temperature without using more electricity than necessary.

It is a bit like driving a car. You don’t accelerate as hard as possible all the way to your destination and then slam on the brakes. Once you are at the speed you want, you ease off and maintain it.

An inverter heat pump does something similar.

The big difference is energy consumption

For most pool owners, this is probably the part that matters most.

Heat pump efficiency is measured using something called COP, or coefficient of performance. It tells you how much heat the machine can produce compared with the electricity it uses.

A conventional on/off pool heat pump might achieve a COP of around 4 under favourable conditions. In other words, 1 kW of electricity could produce roughly 4 kW of heat.

An inverter heat pump can do considerably better when it is running at reduced output. Depending on the model and the conditions, some inverter systems can reach COP figures of up to around 16 at low operating speeds.

That does not mean it will run at COP 16 all the time. Weather, humidity, pool temperature and the speed at which the compressor is running all affect the result.

The important point is that an inverter has the ability to operate much more efficiently when the pool only needs a small amount of heat.

Why this matters over a whole swimming season

Think about what happens after your pool has reached the temperature you want.

The pool doesn’t suddenly need the same amount of energy it needed when it was cold.

It may only lose a small amount of heat through evaporation, wind and the surrounding air. A standard heat pump still has to switch on at full power when the temperature drops enough.

An inverter can reduce its output and replace that lost heat gradually.

That means it can spend much of its time running gently rather than repeatedly starting at full power.

Over weeks and months of pool heating, those differences add up.

Inverter heat pumps also have a softer start

There is another advantage that doesn’t get quite as much attention.

A conventional on/off heat pump can draw a significant amount of current when the compressor starts. An inverter unit uses a softer start, gradually bringing the compressor up to speed rather than hitting the electrical supply with a large startup demand.

This can be useful in homes where the electrical supply is already working hard, particularly when the heat pump is being used alongside other appliances or a solar PV system.

And they tend to be quieter

Because an inverter heat pump doesn’t have to run at full speed every time it operates, it can also be noticeably quieter when maintaining the pool temperature.

Once the water is where you want it, the compressor can slow down.

That is a worthwhile benefit if your pool is close to your home, patio or entertainment area. Nobody wants the sound of a heat pump running at full power when they are sitting outside enjoying the pool.

So, which one should you choose?

If the initial purchase price is your main concern and you only intend to heat the pool occasionally, a standard on/off heat pump may still make sense.

But if you use your pool regularly and want to keep the water at a comfortable temperature for longer periods, an inverter heat pump is worth serious consideration.

The higher purchase price is offset by the way the unit operates. It uses less electricity when maintaining the pool, starts more gently, generally runs more quietly and can adjust its output instead of constantly working at full capacity.

For a pool that is going to be heated regularly, that difference can become important.

Make your pool heating more efficient

At SunScan, we supply inverter pool heat pumps because we believe there is little point in using more electricity than necessary to keep a pool comfortable.

The technology allows the heat pump to respond to the pool rather than simply running at one fixed speed. When more heat is needed, it works harder. When the pool is close to the desired temperature, it backs off.

That is the real advantage of inverter technology.

You are not just buying a heat pump that heats your pool. If required these units can cool your pool in those very hot climates where pools reach uncomfortably high temperatures.

You are buying one that can adjust how hard it works to do the job.

And when a pool heat pump may run for many hours over a swimming season, using electricity more intelligently can make a substantial difference to the cost of keeping the water warm.

Water heating takes 30 to 50% of a South African household’s electricity bill, by Eskom’s own estimate, and the geyser is usually the single biggest item on it. That’s the number a solar geyser and a heat pump both go after, and both do it well, cutting that portion of the bill by more than half in a typical home. Which one suits your house is a different question, and it’s the one we spend most of our week answering, so this is the walk-through we’d give you at your own front door.

When a Solar Geyser Is the Right Call

The whole system depends on direct sunlight, so the first thing to check is your roof:

• An unshaded, north-facing roof: collectors want direct sun through the middle of the day. Get that right and the tank has done most of its heating before lunch.
• A long lifespan: a well-maintained system runs 15 to 20 years, and the simplest versions have almost no moving parts to service.
• An electric backup for winter: systems carry a backup element for overcast weeks, so you still have hot water after days of rain.
• A geyser too young to replace: a conversion keeps your existing tank and adds the collector, which costs less than a full new system.

When a Heat Pump Wins

A heat pump works like a fridge in reverse, pulling warmth out of the outside air, and it delivers three to four units of heat for every unit of electricity it draws:

• No roof required: it sits at ground level beside the geyser, which settles the question for shaded houses, flats and estates with rules about what goes on the roof.
• Cloudy weather has little effect: it runs on air temperature, so it loses a little efficiency in a cold week and keeps working.
• A straightforward retrofit: it connects to the electric geyser already in your ceiling, and the tank stays where it is.

What They Cost in 2026

Current market pricing in Cape Town runs like this, installed:

• A solar geyser: R22,500 to R39,500 depending on tank size and system type, with conversions of an existing geyser coming in lower.
• A heat pump: R25,000 to R45,000 depending on capacity.

Both routes typically pay for themselves in three to five years through the electricity they stop using, and both keep working for a decade or more after that. Exact pricing depends on your tank size, your roof and how much hot water your household uses, so a final figure needs a quote.

The Bill Only Moves in One Direction

Eskom’s tariff rose 13.67% in April 2026, and every month of heating water on a plain electric element is another month at full price. SunScan supplies SABS-tested solar geysers and heat pumps with warranties of up to 5 years, fitted through our network of accredited installers across Cape Town and the Western Cape, and in most homes the roof settles the choice.

In South Africa, having a pool is part of the lifestyle, but for many homeowners, it’s only truly usable for a few months of the year. As soon as temperatures drop, even slightly, the water quickly becomes too cold to enjoy. At the same time, rising electricity costs make traditional pool heating methods expensive to run.

This is where pool heat pumps have become the go-to solution. They offer one of the most cost-effective ways to heat your pool, allowing you to extend your swimming season without worrying about excessive energy use.

A pool heat pump doesn’t generate heat like a traditional electric heater. Instead, it extracts heat from the surrounding air and transfers it into your pool water. This simple shift in technology makes a big difference. Because the system moves heat rather than creates it, it can deliver significantly more energy than it consumes. In optimal conditions, heat pumps can achieve a Coefficient of Performance (COP) of 5 or higher, meaning you get up to 5 units of heat for every 1 unit of electricity used. Compared to electric resistance heaters (which operate at a COP of 1), this results in much lower running costs.

To get the best performance and lowest costs, a few key factors matter. Here’s how to make the most of your pool heat pump:

Correct Sizing

Your heat pump must match your pool size.

A unit that’s too small will struggle and run continuously, while an oversized unit may cost more than necessary upfront.

Ambient Air Temperature

Heat pumps perform best in milder climates — which makes them ideal for South Africa. Warmer air improves efficiency, allowing your system to heat your pool faster and more economically.

Inverter Technology

Modern inverter pool heat pumps adjust their output based on demand. This means:

• Lower energy consumption
• More stable temperatures
• Quieter operation
• Longer lifespan

Where and how your heat pump is installed has a direct impact on efficiency. A professional installation ensures your system performs as intended from day one. For best results:

• The unit needs to be placed in an area with good airflow
• Confined or obstructed spaces need to be avoided
• Plumbing distances should be kept short
• Ensure proper integration with your filtration system

South Africa’s climate is ideal for heat pump performance. With the right approach, you can comfortably extend your swimming season without increasing your energy bill significantly.

You can maximise efficiency by:

• Heating your pool during spring and autumn (shoulder seasons)
• Running your system during warmer parts of the day
• Pre-heating water ahead of cooler evenings or load shedding

Even the best system won’t perform well if the basics are overlooked. Issues such as installing an undersized unit, ignoring correct water flow rates, poor insulation on pipes, or running the system without a pool cover can all reduce efficiency and increase running costs. Avoiding these common mistakes ensures your heat pump performs optimally and that you get the full benefit from your investment. A professional installer will be able to advise you on these issues.

If you’re looking for the most economical way to heat your pool in South Africa, a heat pump is one of the best options available.

It allows you to extend your swimming season, reduce running costs, use energy more efficiently, and ultimately enjoy your pool more often.

With the right system, installation, and maintenance, your pool becomes a year-round feature,  not just a summer luxury.

SunScan offers high-performance Pool Heat Pumps designed for South African conditions, helping you enjoy warmer water for longer, without the high electricity cost.