How much does it cost to run a hot water cylinder in NZ?
Hot water is one of the biggest costs on your power bill. EECA says water heating makes up around a third of household energy bills. Here's what that means in dollars.
The short answer: about $1,000 a year
A typical NZ household uses about 8,000 kWh of electricity a year, the figure MBIE uses to model household power prices. About 30% of that goes on heating water, or around 2,400 kWh. At the national average price of 42.1c per kWh (MBIE, August 2026), a standard electric cylinder costs about:
- $1,010 a year
- $84 a month
- $2.77 a day
What it costs by household size
This table spreads that typical 2,400 kWh across a family of four. Your actual use will vary with your showers, appliances and habits.
| Household | Standard electric cylinder (per year) | Solar thermodynamic system (per year) | Yearly saving |
|---|---|---|---|
| 1 person | $253 | $77 | $176 |
| 2 people | $505 | $154 | $352 |
| 3 people | $758 | $230 | $527 |
| 4 people | $1,010 | $307 | $703 |
| 5 people | $1,263 | $384 | $879 |
Standard cylinder: 600 kWh per person per year. Solar thermodynamic: about 0.5 kWh per person per day. Both at 42.1c per kWh.
Where you live makes a difference
Power prices vary a lot around the country. In April 2026, MoneyHub found prices ranging from 34.61c per kWh in Wellington to 48.93c in Balclutha. The same 2,400 kWh would cost about $831 a year in Wellington and $1,174 in Balclutha.
Why a standard cylinder costs so much
A standard electric cylinder uses a heating element, like a giant jug. Every unit of heat in the water costs you one unit of electricity. It also loses heat through its walls around the clock, so you pay to keep water hot even when no one is using it.
How to cut the cost
- Use less hot water: shorter showers, cold washes and full dishwasher loads all help. EECA has more tips.
- Check your power plan: many retailers offer a cheaper controlled or night rate for hot water. Ask yours what's available.
- Upgrade the system: a solar thermodynamic system collects most of its heat from the sun and the air, so it uses a fraction of the electricity. For a family of four, that's around $700 a year back in your pocket. See our worked savings example for the full calculation.
- Switching from gas? See gas vs electric hot water.
Want to know what you could save? Contact us or call 03 540 3003 for a free estimate. Choosing a new system? Start with what size hot water cylinder you need.
Figures are indicative, based on national averages. Your costs will depend on your household, usage, power plan and location.