Heat Pump vs Solar vs Gas Geyser Calculator (South Africa)
Puts a heat pump, solar geyser and gas geyser quote on the same household and climate, then shows which one costs less to run and which pays back first.
You have three quotes on the table: a heat pump, a solar geyser, and a gas geyser. This tool puts them on the same household and the same climate, then shows which one actually costs less to run and which pays back first. The ranking is allowed to flip. A Highveld winter is kind to evacuated tubes and hard on a heat pump. Cape Town's wet winter is the other way around.
Everyone drawing hot water at home, not just adults.
Sets litres per person per day at your geyser's setpoint (60°C). Typical is about 40 litres a person, the plumbing industry planning figure, not mixed-to-40°C tap litres.
Drives the heat pump and the solar geyser. A tankless gas geyser does not use it. Keep it set to the electric tank you have now, or the solar/heat-pump tank you are being quoted.
Sets the heat pump's seasonal COP, the solar geyser's seasonal solar fraction, and your incoming water temperature. This is the lever that can flip the ranking.
A timer only cuts standing heat loss on a storage tank (electric, heat pump, solar). A tankless gas geyser has no tank, so the timer does nothing there.
How concentrated your heaviest draw is. This is what determines whether a heat pump's slower recovery leaves you finishing a shower in cold water.
For the gas geyser only. Each shower is assumed 9 litres a minute mixed. A 16 L/min unit covers two showers; a third needs a bigger unit.
One control, applied to all three quotes. If the geyser is already dead, the capital you actually stake is only the extra over a same-size electric replacement. If it still works, you stake the full installed cost, a working geyser has no resale value.
A retrofit is only possible while your existing tank is still sound. Solar usually replaces the tank. Gas removes it. Neither has a keep-the-tank option here.
Auto-filled from a typical installed quote at this tank size, anchored to a real 200 L integrated unit at Builders in 2026 (R27,999 plus a R6,280 install). Overwrite with your actual quote.
A R30,000-class 2026 quote is usually 20 evacuated tubes. Flat plate is cheaper capital and a worse Highveld or Karoo winter. Direct thermosiphon is fine in Cape Town and Durban; Highveld and Karoo need freeze protection on a flat plate, which this tool haircuts.
A 2026 Gauteng installer quote for a 200 L Kwikot tank with 20 evacuated tubes, standard install up to 4 m. CoC and a timer are extra. Overwrite with yours.
Paloma-class quality units, not a R6,000 Builders special. Default 16 L/min covers two showers at 9 L/min mixed.
A 2026 Paloma Preferred Installer package for a 16 L Eco Lite: unit, gas line, water plumbing and CoC. Cylinder deposit, first refill, cage and an electrical point are extra. Overwrite with yours.
What a like-for-like electric replacement would cost you, unit plus a Certificate of Compliance install. Only counted against each upgrade when your geyser just died, since that is the money you'd spend either way.
Rands per kWh. Use your top marginal block, not your average bill divided by units, since water heating is the extra kWh sitting at the top of an inclining block tariff.
Applied to both electricity and LPG. They do not actually move in lockstep; one slider is the honest v1 shape rather than a second one that looks precise and is not.
What you actually pay per kilogram on a 9 kg exchange, not the empty cylinder. Default is a July 2026 regulated-max round number (about R40.84/kg Saldanha MRP). Overwrite with last week's slip.
Default is a booked technician visit. You can clean the evaporator yourself; Kwikot's full accredited service is every 2 to 3 years, not every year. A booked visit is typically R500 to R1,350. Overwrite if you have a contract, or drop it if you do the coil yourself. An electric geyser has no equivalent.
Glycol check, anode and pump on an indirect system, less on a simple thermosiphon. Counted because an electric geyser does not need it.
The honest cost of tying up cash in the upgrade instead of a money market account. Defaults to 6%, a realistic after-tax return. Set to 0 to ignore it. Shown in each upgrade's drag list, not as a fourth column.
A quality heat pump is typically good for 10 to 15 years. A solar geyser tank is similar. 12 is a reasonable middle.
Which quote actually wins here
--
What the brochure leaves out
Starts at the salesman's figure over the comparison years, then takes off climate, servicing and the interest that capital could have earned. Ends at cash after interest, which is discounted. Same rand scale on all three quotes.
The lists below split each climate bar into the named haircuts.
What closes the gap on the heat pump
What closes the gap on the solar geyser
What closes the gap on the gas geyser
Totals over the whole comparison period in future rands, which is why they look larger than a single month's bill. A drag of R0 is omitted.
Money in your pocket over time
Estimates to sanity check three quotes on the same household, not a substitute for any of them. Get tank size, collector type, compressor rating, gas unit flow rate and warranty terms in writing before you decide. Want the heat pump sizing check in more detail? Use the heat pump vs electric geyser calculator. Looking at panels for the whole house, not a collector on the geyser? That is the solar savings calculator.
💬 Questions about a heat pump, solar or gas quote? Discuss this tool on the forum →
More household tools: Heat Pump vs Electric Geyser · Solar Savings Calculator · Prepaid Electricity Calculator · Municipal Water Bill Calculator
Heat pump vs solar vs gas geyser cost, on the same household
The heat pump calculator on this site sizes one quote against a plain electric geyser. A homeowner holding that quote is usually holding two more: a solar geyser and a gas geyser. Those are different machines. A heat pump is seasonal COP and tank recovery. A solar geyser is seasonal solar fraction, with the rest on the element. Instantaneous LPG is kilograms of gas, tankless, no standing loss. Putting all three on extra columns of the heat pump page would bury the sizing check that page already does well.
The ranking is allowed to flip by climate. That is the finding that makes a fourth page worth building. Highveld and Karoo winters are harsh for a heat pump and strong for evacuated tubes. Cape Town is kinder to the compressor and weaker for solar thermal, because the wet winter is when you want the hot water. Gas is the cheap quote and the expensive kilogram, about R3.46 per useful kWh at R40/kg, versus about R1.22 for a national-average heat pump on a R3.20 tariff.
Starting prices are named 2026 quotes, not ranges from blogs, and solar fraction is locked to Stellenbosch field data plus an inland-versus-coastal gap, not a flat national 70 percent that would erase the reversal. Overwrite every figure with the quote in your hand.
How much does a heat pump, solar geyser or gas geyser cost in South Africa?
Named 2026 quotes, not blog ranges. A 200 litre integrated heat pump at Builders was R27,999 plus a R6,280 install, R34,279 all in. A 200 litre Kwikot tank with 20 evacuated tubes, fully installed by Juspropa, is R29,500. A Paloma 16 litre-per-minute Eco Lite from a Paloma Preferred Installer is R10,850 for the unit and from R20,500 installed. Those are starting points. Overwrite them with the paper in your hand.
On the default four person household at R3.20/kWh, with the geyser still working, an electric geyser costs about R960 a month to run. The heat pump is about R430, the solar geyser about R290, and instantaneous LPG about R830. The kWh cut on solar and the heat pump is larger than the rand cut, because a booked annual service is counted and winter is below the brochure.
How long until each quote pays for itself?
On those same defaults, the solar geyser pays back in about 3.3 years, the heat pump in about 4.6 years, and gas in about 9 years. If the geyser has already died you only stake the extra over a same-size electric replacement, and those shorten to about 2.1, 3.2 and 4.8 years. A typical R16,000 heat pump retrofit on a sound tank lands around 2.4 years, which is why that path exists on the sibling calculator too.
Installer pages often pick one winner for the whole country. This tool does not. On matched capital, Cape Town usually favours the heat pump; on the Highveld the two are close and a cheaper solar quote tips it. Gas wins the first year on cheap capital and usually loses the tenth on the kilogram. Type the three quotes and the climate, then read the ranking that actually applies to the house.
How the three engines differ
All three share the household: litres at 60°C setpoint, the same five climates, the same dead-versus-working capital fork. If the geyser has already died, you only stake the extra over a same-size electric replacement. If it still works, you stake the full installed cost, because a working geyser has no resale value. A retrofit heat pump is only offered while the tank is still sound. Solar usually replaces the tank. Gas removes it.
The heat pump path is a copy of the live calculator, seasonal COP as a harmonic mean, backup element at COP 1 on the morning-peak shortfall. The solar path uses an arithmetic mean of seasonal solar fraction, because backup kWh is thermal load times one minus SF. Copying the COP harmonic helper onto SF would understate summer and is a test-gate failure. The gas path charges draw energy only. Standing loss is a real advantage of tankless, and charging it would be a copied bug.
Related tools
Want the heat pump sizing check in more detail, tank and recovery against your morning peak? Use the Heat Pump vs Electric Geyser Calculator. Looking at panels for the whole house, not a collector on the geyser? That is the Solar Savings and Payback Calculator. To see what a rand of electricity actually buys on your tariff, use the Prepaid Electricity Calculator.
Frequently asked questions
Why does a heat pump beat a solar geyser in Cape Town and lose on the Highveld?
A heat pump's efficiency follows outside air temperature. Cape Town's winter is mild enough that the compressor still runs at a useful COP, while a solar geyser's collector is looking at the wet season, which is when you actually want the hot water. Stellenbosch field data on a 2.4 square metre flat plate put the annual solar fraction at 70.4 percent, with winter months closer to half. On the Highveld the winter is cold and dry: the heat pump's COP drops and evacuated tubes still collect. The ranking is allowed to flip. That is the point of putting both quotes on the same household.
Is a gas geyser actually cheaper?
It is the cheap quote and the expensive kilogram. A Paloma-class 16 litre-per-minute unit installed sits around R20,500 in 2026, well below a heat pump or a 200 litre solar geyser. At R40 per kilogram, 13.6 kWh per kilogram and 85 percent efficiency, useful heat costs about R3.46 per kWh. A national-average heat pump on a R3.20 tariff is about R1.22 per useful kWh. Gas wins the first year and usually loses the tenth. It is also the only one that still showers during an outage, which this tool reports as a bonus, not as a rand in the payback.
What is the cheapest way to heat water in South Africa?
It depends on your climate and on whether the geyser is already dead. If it has died, you only stake the extra over a same-size electric replacement, which shortens every payback. If it still works, you stake the full installed cost. On matched capital, Cape Town usually favours the heat pump; on the Highveld the two are close and a cheaper solar quote tips it. Gas is rarely the cheapest to run. Type your three quotes in and let the climate do the ranking.
How much does a solar geyser cost installed in South Africa?
A 200 litre evacuated-tube system is the quote most four person homes are holding. The 2026 named figure in this tool is a Juspropa 200 litre Kwikot tank with 20 tubes at R29,500 installed, CoC and a timer extra. Smaller tanks step down toward R24,000, larger ones toward R38,000. Flat plates are a few thousand cheaper and lose more on Highveld frost nights. Overwrite with the number on your paper. Brochure figures that start at R18,000 are often the tank and collector only.
How much does a gas geyser cost to run a month in South Africa?
On the default four person household, instantaneous LPG at R40 per kilogram costs about R830 a month. That is 0.68 kilograms a day, a 9 kilogram bottle every two weeks. An electric geyser on the same household is about R960, a heat pump about R430, a solar geyser about R290. Gas is cheaper than the electric baseline and more expensive than the other two upgrades. The cheap capital, from R20,500 installed, is why it still wins the first year on a working geyser, and why it usually loses the tenth.
Heat pump vs solar geyser in Johannesburg, who actually wins?
On the Highveld, evacuated tubes usually win the running-cost contest. Pretoria-class field numbers put annual solar fraction around 80 percent, and the heat pump's winter COP drops to about 2.1. On this tool's default four person, 200 litre household, the solar geyser runs about R260 a month and the heat pump about R430. Payback on the named quotes is about 3 years for solar and 4.5 for the heat pump, if the geyser still works. Cape Town is the climate that can reverse that ranking on matched capital, because the wet winter is when you want the hot water and the compressor still has a useful COP. Pick Johannesburg or Pretoria Highveld in the climate box rather than taking a national average.
Solar geyser vs gas geyser, skipping the heat pump?
On running cost the solar geyser wins almost everywhere, because the backup is still an electric element at your tariff, not LPG at R3.46 per useful kWh. Gas wins on cheap capital and on hot water during an outage. If your roof cannot take a collector, or you want a tankless unit, gas is the honest remaining option, not the cheaper kilogram.
What is solar fraction, and why is it not the 80 percent on the brochure?
Solar fraction is the share of the tank's thermal load the collector actually supplies. The rest runs through the backup element at COP 1. Brochure numbers are often a flat 85 percent with no winter derate. This tool uses a three-season table locked to Stellenbosch CRSES 2018-19 field data for Cape Town (annual 70.4 percent on a 2.4 square metre flat plate) and Agyekum 2024 modelled city gaps for Pretoria, Kimberley and Durban. Highveld and Karoo flat plates take a further 5 point freeze-protection haircut, because those climates need an indirect glycol system.
Do I need an indirect system in Johannesburg?
Yes if the collector is a flat plate. Highveld and Karoo nights freeze, so a direct thermosiphon on a flat plate is a burst-tube risk. Evacuated tubes are typically freeze tolerant, which is why they are the default collector in this tool and why the freeze haircut applies only to inland flat plates. Cape Town and Durban can run a direct thermosiphon without that penalty.
Why is the Paloma 16 L/min quote around R20,500 when Builders sells a 16 L unit for R6,000?
The R6,000 units are a different product: often a single-shower, battery-spark, no-fan heater sold as a kit. The quote sitting next to a R30,000 heat pump is a quality fan-forced unit plus a registered gas fitter, the gas line, water plumbing and a Certificate of Compliance. The 2026 named quote is a Paloma 16 L Eco Lite from a Paloma Preferred Installer at R10,850 for the unit and from R20,500 installed. Cylinder deposit, cage and an electrical point are extra. Overwrite with yours.
What about PV panels on the geyser element?
That is a third product: panels driving a resistive element, not a collector on a tank and not a whole-house solar system. Stellenbosch measured it, and it stays out of this comparison. If you are sizing panels for the whole house, use the Solar Savings and Payback Calculator. Folding PV-to-element into this page would mix three SERPs and three honesty models.
Can I combine solar and gas?
Yes, a gas unit can cover the solar shortfall, which is a common installer package. It is out of this version because it is a fourth capital number and a different running-cost shape (gas kilograms only on the backup, not on the whole draw). Type the solar quote here and treat gas as the outage backup until a hybrid mode exists.
Does a geyser timer change the ranking?
Only a little, and only on storage systems. A timer clips standing heat loss on the electric baseline, the heat pump and the solar geyser. A tankless gas geyser has no tank, so the timer does nothing there. The folklore that a timer cuts the bill by a third is standing-loss folklore, not draw energy.
Where do the numbers come from?
Heat pump capital and COP are copied from the live Heat Pump vs Electric Geyser Calculator (Builders 2026 Kwikot HP-200-V, peer-reviewed SA seasonal COP). Solar capital is a 2026 Juspropa quote for a 200 litre Kwikot tank with 20 evacuated tubes, fully installed, R29,500. Gas capital is a 2026 Paloma 16 L Eco Lite installed package from The LpGas Man, from R20,500. Solar fraction is Stellenbosch CRSES 2018-19 plus Agyekum Energy Reports 2024 for city gaps. LPG is 13.6 kWh per kilogram at 85 percent, default R40 per kilogram as a July 2026 regulated-max round number. This page does not use marketing comparison sites.
Estimates to sanity check three quotes on the same household, not a substitute for any of them. Get tank size, collector type, compressor rating, gas unit flow rate and warranty terms in writing before you decide. Last reviewed August 2026.