Confused Kiwis are struggling to get their heads around their electricity bills.
A Canstar Blue survey of more than 4250 consumers found more than a third of us don't know how to read our power bills, and independent mediator Utilities Disputes said the number of complaints about billing was rising.
Meanwhile, a Credit Simple survey of 1600 people found the threat of high bills was keeping Kiwis from using their heating in winter.
Aucklander Leah Craven knows more about her bills than most, having chosen a plan which uses redistributed solar power because she is against the use of coal.
Even so, Craven said she still wasn't sure how all her rates were calculated.
"I'd say I've got a medium understanding of my power bill and I'd say that is quite unusual. I would say a lot of people really don't understand their electricity bill.
"I don't understand a lot of the cost, how it's worked out."
Utilities Disputes commissioner Nanette Moreau said this was common and could result in unexpected high or back bills.
Billing issues had always made up a majority of the organisation's complaints but in the last year that number had risen from 55 to 75 per cent.
The organisation (formerly the office of the Electricity and Gas Complaints Commissioner) deals with about 6000 complaints a year.
"When a person is signing up with a retailer it's important to provide as much information as they can," Moreau said.
That included knowing what kind of meter was installed at your home and if possible sending a photo to the power company to check.
It was important to know what kind of meter was at your household if, for example, a customer signed up to a plan which charged a cheaper rate for daytime electricity.
If their meter wasn't equipped to tell the time then the consumer wouldn't see the benefit of the plan, Moreau said.
Confusion about how power was charged for and unexpected fees were also among reasons people complained.
Utilities Disputes had managed to get a 50 per cent price reduction for one customer charged $7000 in back bills after his energy company realised they'd been reading his neighbour's meter in error for more than a year.
Another woman had the price difference of an unusually high bill refunded after complaining her electricity company had accidentally terminated her account over winter, meaning she hadn't been able to keep track of how much energy she'd been using.
Moreau said in the first instance people should talk to their power companies to try to resolve any unexplained charges, but if that didn't work they could call Utilities disputes on 0800 22 33 40.
Credit Simple chief executive David Scognamiglio said many Kiwis were worried about high bills and unsure what they'd be charged before the bill arrived.
Signing up with a power company which allowed you to see electricity price forecasts was a way to "gamify" your power bill, regain control over spending and keep energy costs low, he said.
Energy startup Flick and Genesis energy were among those companies providing apps for customers to check energy price forecasts.
"Being able to look forward and understand the market, almost like a stock market, is really clever."
Knowing power would be cheaper at 2am, for example, meant you could time your dishwasher to run its cycle after you went to bed.
"If you're always eyeballing that then you don't have to wait for a bill after the fact".