How much does a heated towel rail cost to run in NZ?

About $254 a year for a typical 80W rail left on permanently, at the national average variable rate. Bigger rails cost proportionally more - a 150W square-bar unit runs to around $477 a year on the same always-on schedule.

Should I turn my heated towel rail off?

Not necessarily off - on a timer. Switching it off entirely saves the most money but gives you damp towels and, in a poorly ventilated bathroom, more moisture sitting in the room. Four hours a day in two blocks costs about $42 a year, dries towels perfectly well, and saves roughly $212 against leaving it on. A plug-in or in-wall timer costs about $20.

Does a heated towel rail stop mould in the bathroom?

It helps a little, by drying the towels that would otherwise hold moisture, but it is a poor tool for the job and an expensive one. The moisture in a bathroom comes overwhelmingly from showering, and the answer to that is extraction - a working extractor fan vented outside, run during and for fifteen minutes after a shower. A rail run around the clock to control mould is treating a ventilation problem with a heater.

Do heated towel rails use a lot of power?

Not per hour - a towel rail draws less than two old-fashioned lightbulbs. The cost comes entirely from the hours. It is the clearest example on the whole site of why wattage alone tells you nothing: this rail is one of the lowest-wattage things in the house and still costs more per year to run than the oven, the kettle and the microwave put together, purely because nobody ever switches it off.

Running cost

Is your heated towel rail really costing you $250 a year?

By Jason Webb· Published 6 August 2026· Updated 6 August 2026· 6 min read

A heated towel rail draws about 80 watts. That is less than two old incandescent bulbs, and it is why nobody thinks about it. It has no thermostat, no display, often no switch you can see - it was on when you moved in and it has been on ever since.

Left running permanently, it costs roughly $254 a year. That is more than the oven, the kettle and the microwave combined, and it is the single clearest demonstration of the rule that runs through this whole site: wattage tells you nothing, wattage times hours tells you everything.

What the schedule is worth

Annual cost of a 80W towel rail at 36.3c/kWh, by how long it runs each day
Schedule	Per year	Saved vs always on
Left on permanently	$254	-
12 hours a day	$127	$127
6 hours a day	$64	$191
4 hours a day	$42	$212
2 hours a day	$21	$233

The interesting row is four hours. Two two-hour blocks - one after the morning showers, one in the evening - dries towels completely, and saves about $212 a year. A plug-in timer or an in-wall switch timer costs around $20, so it pays for itself in roughly 5 weeks and then keeps returning every year after that. There is very little else in a house with that payback.

Not all rails are 80 watts

Rail wattage scales with size, and the difference between a modest ladder in an ensuite and a wide square-bar rail in a main bathroom is substantial:

Annual cost by rail size, left on permanently
Rail	Draw	Per year, always on
Small 4-bar ladder	60W	$191
Typical 6-bar ladder	80W	$254
Large 8-bar ladder	120W	$382
Wide square-bar rail	150W	$477

If you have two rails - a main bathroom and an ensuite, which is common in newer houses - double whichever row applies. A pair of large rails left on is comfortably over $600 a year, which is getting into the territory of a serious heating appliance.

The mould objection, taken seriously

There is a real counter-argument to switching the rail off, and it deserves a straight answer rather than being waved away. New Zealand bathrooms are damp, mould is a genuine health issue, and a warm rail does dry towels that would otherwise stay wet and hold moisture in the room.

All of that is true, and it still does not justify running the rail around the clock. The moisture in a bathroom comes overwhelmingly from the shower itself, not from towels, and the tool for removing it is extraction - an extractor fan that actually vents outside rather than into the ceiling cavity, run during the shower and for about fifteen minutes afterwards. That removes the water vapour before it condenses on anything.

A towel rail run continuously is a ventilation problem being treated with a heater, and an expensive one. Fix the extraction, then put the rail on a timer, and you get a drier bathroom and the saving.

What to actually do

Find out if it is even switched. Many rails are wired to a wall switch that has been taped over or forgotten, or to no switch at all. That is the first thing to establish.
Fit a timer. A plug-in timer if the rail is on a socket, an in-wall timer switch if it is hardwired. Two blocks a day.
Check your extractor fan actually vents outside. A surprising number vent into the roof space, which relocates the moisture rather than removing it.
Count your rails. The ensuite one is easy to forget and costs the same as the one you remember.

To price your own rail and schedule, open the calculator. For the other loads that cost more than people expect for the same reason, the full appliance table ranks all 45 - the second fridge is the towel rail's closest cousin.