What does a instant electric shower cost to run?
A typical instant electric shower used for its typical minutes per day costs about $29/month to run in New Zealand - that's $345/year at the current national average rate of 42.0c/kWh. Very high wattage but only on during the shower
| Region | Rate | Monthly |
|---|---|---|
| Dunedin | 42.4c/kWh | $29 |
| Queenstown | 42.3c/kWh | $29 |
| Auckland Central | 41.2c/kWh | $28 |
| Christchurch | 38.5c/kWh | $26 |
| Wellington City | 37.0c/kWh | $25 |
This estimate models a typical instant electric shower used for its typical minutes per day. At the national average rate of 42.0c/kWh, that works out to about 68 kWh a month - $29/month, or $345 across a year.
- Power draw
- 9,000 W
- Typical use
- 15 min/day, 7 days/week
- Rate applied
- 42.0c/kWh (national average)
- Energy used
- 68 kWh/month · 821 kWh/year
Your own usage will differ - adjust the hours, wattage and rate for your household in the full calculator.
What to know about running a instant electric shower
An instant electric shower heats water on demand as it flows, so it skips the standing heat losses of a stored cylinder. There is no tank sitting hot all day quietly reheating itself, which is a real advantage in a home or a second bathroom where hot water is only wanted occasionally.
The headline figure is alarming, around 9,000-10,000W, one of the highest-wattage things in the house. That number frightens people into thinking an instant shower must be ruinously expensive to run. But it only draws that power while you are actually showering, and the rest of the day it uses nothing at all.
That makes the real cost all about shower time. A short shower is cheap because the heater is off for the other 23-and-a-bit hours. A long one is expensive precisely because of that huge wattage, so every extra minute under the water is costing you at close to the highest draw in the house.
The gotcha, then, is not the shower itself but the habits around it. A leisurely ten or fifteen minute shower on a 9kW unit quietly adds up, while the same unit barely registers for someone in and out in three. It rewards being quick and punishes lingering more sharply than almost any other appliance.
For one- or two-person households, or a rarely used second bathroom, an instant shower can beat keeping a whole cylinder hot, because you never pay for standing losses on water you are not using. This is where the on-demand design genuinely wins.
For a busy family taking lots of long showers, a well-managed cylinder on a night rate usually wins instead, because it heats a big volume cheaply overnight and shares it across everyone. Which setup is cheaper really depends on how many people shower and for how long. Either way the lever is the same: minutes under the water.
Because the cost swings so hard on time, this is a good row to experiment with in the calculator. Try your honest shower length against a shorter one and you will see the difference a couple of minutes makes, repeated every day of the year.
Frequently asked
How much does a instant electric shower cost to run in NZ?
At the national average electricity rate of 42.0c/kWh, a typical instant electric shower costs about $29 per month, or $345 per year. Actual costs vary by region and how heavily you use it.
Which NZ region has the cheapest instant electric shower running cost?
Of the five centres shown on this page, Wellington City is the cheapest at $25/month, and Dunedin is the most expensive at $29/month. The 30% spread reflects regional MBIE retail rates.
Related running costs
More hot water appliances people ask about:
Browse all appliance costs