How much does hot water cost in New Zealand?

Hot water is often around a third of a power bill. The cost depends on how many people use it, the water heating type, and your power price. This calculator estimates the annual cost for your household.

How can I cut hot water costs?

Shorter showers, an efficient shower head, fixing drips, and an efficient cylinder such as a heat pump water heater all help. A heat pump cylinder uses far less power than a standard electric one.

Is a heat pump water heater worth it?

A heat pump cylinder can deliver hot water using a fraction of the electricity of a standard element, so it can cut hot water costs substantially, though it costs more to install.

Hot Water Cost Calculator

This calculator estimates how much your hot water actually costs to heat over a year, one of the largest items on a New Zealand power bill and often around a third of the total. You enter the number of people in your household, the hot water energy used per person each day in kilowatt-hours, the type of water heating you have, a standard electric cylinder, a heat pump cylinder, or gas, and your power price per kilowatt-hour. From these figures the calculator works out the energy needed to heat your household's water, adjusts for how efficient your heating type is, and multiplies the result by your power price across the year. It returns your estimated annual hot water cost, broken down into a weekly figure and a cost per person per year, plus a comparison showing what the same hot water use would cost with a heat pump cylinder instead, since a heat pump delivers the same hot water using a fraction of the electricity of a standard element. Use it to see where hot water sits in your power spending, to test how shorter showers or an efficient shower head might lower the daily energy figure, or to weigh up whether a heat pump cylinder is worth the upfront cost. Power prices and habits vary, so treat the figures as an indicative estimate rather than an exact bill.

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People in the household

Hot water energy per person (kWh/day)

Water heating type

Power price ($/kWh)

estimated hot water cost per year

Per week$0

Per person per year$0

Heat pump cylinder cost$0

Hot water energy per person is a rough average; heavy shower use raises it. The heating type adjusts for efficiency, with a heat pump cylinder using a fraction of a standard element. Power prices change, so use your current rate. Estimate only.

How it works

The calculator estimates the energy used to heat water as the people times the energy per person, adjusted for the efficiency of your water heating type, then multiplies by your power price across the year. A standard electric cylinder uses one unit of power per unit of heat, while a heat pump cylinder delivers the same hot water for far less, which is why it shows a much lower cost.

Worked example

A 3-person household using 3.5 kWh each a day with a standard electric cylinder at 28 cents costs about $1,073 a year. A heat pump cylinder, around three times as efficient, would deliver the same hot water for roughly $358, showing the saving on offer.

Related calculators

Electricity Cost Calculator: appliance costs.
Appliance Running Cost Calculator: any appliance.
Home Heating Cost Calculator: heating costs.
Power Plan Comparison Calculator: compare power plans.

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