How do I work out an appliance running cost?

Multiply the appliance power in kilowatts by the hours you use it to get the energy used, then multiply by your power price. This calculator does it for the cost per hour, week and year.

How do I find an appliance wattage?

It is usually on a label on the appliance or in the manual, in watts. Divide watts by 1000 to get kilowatts. Heaters and dryers draw a lot; small electronics draw little.

Which appliances cost the most to run?

High-wattage appliances used for long periods, like heaters, dryers and old fridges, cost the most. Working out the cost helps you decide what to use less or replace.

Appliance Running Cost Calculator

This calculator works out exactly what any electrical appliance costs to run in New Zealand, turning its power draw and how often you use it into a real dollar figure, so you can see at a glance which appliances are quietly draining your power bill and which barely register. Appliances are rarely compared fairly, because a small appliance run constantly can cost more than a big one used briefly, and this tool removes the guesswork. You enter the appliance's power rating in watts, found on its label or in the manual, along with how many hours a day you typically use it, how many days a year it gets used, and your power price in cents per kilowatt hour from your power bill. From these figures the calculator returns the cost to run the appliance per year as the headline figure, plus a breakdown of the cost per hour, the cost per day, and the total energy used per year in kilowatt hours. Use it to compare appliances like heaters, dryers, fridges and pool pumps, to decide which ones are worth replacing with an efficient model or using less, and to sanity-check a suspiciously high power bill. Because power prices and usage patterns vary and appliances rarely run at a perfectly constant wattage, treat the result as a close estimate rather than an exact bill figure.

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Appliance power (watts)

Hours used per day

Days used per year

Power price ($/kWh)

cost to run per year

Per hour$0

Per day$0

Energy per year0 kWh

Find the wattage on the appliance label or manual. High-wattage appliances used for long periods cost the most. Power prices change, so use your current rate. Estimate only.

How it works

The calculator converts the wattage to kilowatts, multiplies by the hours used to get the energy per day in kilowatt hours, then by the days per year and your power price. The result is the annual running cost, broken down to a cost per hour and per day. Comparing appliances this way shows which ones are quietly expensive and worth using less or replacing with an efficient model.

Worked example

A 2,000 watt heater used 4 hours a day for 150 days uses 8 kWh a day, 1,200 kWh a year. At 28 cents a unit that is about $336 a year, or roughly 56 cents an hour, which adds up over a winter.

Related calculators

Electricity Cost Calculator: power costs.
Hot Water Cost Calculator: hot water cost.
Home Heating Cost Calculator: heating cost.
Power Plan Comparison Calculator: compare power plans.

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