How Many Watts Does a Geyser Use? (And What It Costs You)
24 May 2026 · Plumbers On Duty
Quick answer
- Standard 150L geyser: 3,000W (3kW) element
- Heavy-duty 200L+ geyser: 4,000W (4kW) element
- Compact 100L geyser: 2,000W (2kW) element
- Solar geyser backup element: usually 2,000W
At 2026 Eskom Homepower 4 rates of roughly R3.70 per kWh:
| Element | Cost per hour heating | Daily (2hrs heating) | Monthly |
|---|---|---|---|
| 2kW | R7.40 | R14.80 | R444 |
| 3kW | R11.10 | R22.20 | R666 |
| 4kW | R14.80 | R29.60 | R888 |
How to find your geyser's wattage
- Look at the rating plate on the side of the geyser (usually has "3000W" or "3kW")
- Check the element box if you have it
- Default assumption for a typical 150L SA geyser: 3kW
Why this matters for loadshedding
A 3kW geyser draws 13 amps at 230V. Your house's single-phase incoming supply is typically 60A. That means:
- Geyser + electric oven (15A) + kettle (10A) + lights = 47A — fine
- Geyser + oven + kettle + tumble dryer (12A) + iron (8A) = 58A — close to tripping the main
When loadshedding ends and your geyser kicks on simultaneously with neighbours' geysers, the suburb-level current surge is what causes lights to dim and breakers to trip.
How to cut consumption
- Drop thermostat from 70°C to 60°C — saves 10–15%
- Insulate the geyser with a R300 blanket — saves 5–10%
- Insulate hot pipes with foam lagging — saves 3–5%
- Fit a timer so it only heats when needed — saves 10–25%
- Low-flow shower heads — saves 15–25% on hot water demand
- Heat pump replacement — uses 60% less power than an element
Solar PV + geyser
If you have solar panels, a PV diverter can route excess solar to your geyser element instead of feeding back to the grid. Payback period is typically 2–4 years for a 5kW system.
Need help?
If your geyser seems to be using more power than usual (DB tripping, bill creeping up), the element may be furred up or the thermostat stuck. A geyser service costs R650–R1,400 and usually pays for itself in saved electricity.