Heat pump or solar geyser - when does it pay for itself?

The install cost against the electricity it saves over a standard electric geyser, year by year.

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Example data - to be completed. These numbers belong to a sample household. Move the sliders to your own quote →

Breaks even in year 4

A R 36 000 heat pump saves about R 8 465 in year 1 and is R 212 543 ahead after 15 years.

Breaks even
year 4
The year the savings have covered the cost
Payback
3.8 years
Counting part of the last year
Net gain at 15 years
R 212 543
Savings less the cost and interest
Saved in year 1
R 8 465
Electricity you no longer buy for hot water

What this means

  • The savings cover the R 36 000 heat pump in about 3.8 years.
  • Year 1 saves about R 8 465 (R 705 a month) against an electric geyser; price increases make every later year worth more.
  • After 15 years you are R 212 543 ahead, in rand as spent.
  • Figures are calculations, not advice - no product or installer is recommended.

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Assumptions

  • A heat pump at R 36 000, paid in cash.
  • 175 L of hot water a day from a 150 L tank: about 302 kWh a month on an electric geyser (20 C mains heated to 60 C, plus standing loss).
  • The heat pump has a COP of 3.0: it uses 33.3% of the electricity.
  • Electricity at R 3.50 a kWh in year 1, rising 9% a year.
  • Rand as spent (not adjusted for inflation); servicing, repairs and a replacement are left out.

Where the typical figures come from

  • Hot water is the biggest single load - about 40% of a household bill (34-41% for an Eskom Homepower 4 user). BusinessTech.
  • Install prices (2026): heat pump R27 500-R44 500 (100-150 L), R39 500-R53 500 (200 L), R44 500-R59 500 (250-300 L); solar geyser R22 500-R29 500 (100 L), R25 500-R34 500 (150 L), R29 500-R42 500 (200 L), R32 000-R50 000 (300 L); an electric geyser R4 800-R14 500. The presets use about the middle. EnergyBee heat pumps, 2026, EnergyBee solar geysers, 2026.
  • Heat pump COP 3.0-4.5 (EnergyBee); we start at 3.0 for a South African winter. Solar geyser 60%: Eskom's calculator assumes "a saving of approximately 60%" for a solar geyser or a heat pump and 20 C mains water; a study across 43 African countries found 25-88% for evacuated tubes, depending on the region. Eskom calculator assumptions, AGRIS / FAO.
  • Hot water and tank size: about 50 L a person a day (Eskom's calculator uses 80 L an adult); 100-150 L for 1-3 people, 200 L for 3-4, 250-300 L for 5+. Standing loss: SANS 151 allows up to 2.5 kWh a day on a 150 L tank. Kwikot sizing guide, Kwikot electric geyser guide.
  • Price increases (Low 6%, Moderate 9%, High 13%): the same NERSA figures as the solar calculator. Engineering News, 2026.
  • Estimates, not sourced: the 0.012 kWh per litre a day standing loss for other tank sizes, the 60 C setting, and the hot water per preset. Use your own quote and your own household.

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