As the cost of electricity rises, many New Zealanders will be looking for ways to reign in their power bills.

But how much do tricks like turning appliances off at the wall and taking shorter showers really save?

Research shows some of our most common power-saving exercises make little difference and others, like washing the dishes by hand, can actually be less energy efficient.

However, there are some changes that can save hundreds of dollars a year – and just which appliances are sucking the most power might surprise you.

READ MORE: * How to avoid ramping up the power bill while working from home * Seven ways to lessen your carbon footprint at home (and what that actually means) * Simple mistakes you're probably making with your dishwasher

Although flipping the switch when you leave a room could save a few cents an hour, there are much bigger savings to be made by switching to LED bulbs, according to Consumer NZ product test team leader James le Page.

Despite the higher upfront cost of LEDs, the bulbs quickly pay for themselves through reduced power bills.

A mid-range LED costs $18, draws 9.5 watts of electricity and has an expected lifespan of 15,000 hours.

A 60 watt incandescent bulb, which produces the same light, costs 50 cents but lasts just 1000 hours, le Page said.

“If the light is on for three hours each day the incandescent will use $17.08 worth of electricity in a year, compared to $2.70 for the LED. That’s a saving of $14.38 per year.”

That means the LED bulb will have paid for itself in a little more than a year and will keep going for another 12 years if used for three hours a day, while the incandescent bulb will need to be replaced every year.

“These figures show you shouldn’t wait for your incandescent bulbs to blow – it’s more cost-effective to replace them with LEDs now,” le Page said.

If you're really wanting to save as much as you can, turning appliances off at the wall will completely eliminate power use, le Page said.

However, most appliances use very little electricity in standby mode.

Consumer NZ testing found some technology, including TVs, Blu-ray players and home theatre systems, cost just a few cents each year on standby, while clothes dryers, gaming consoles, washing machines and microwaves left on standby use less than $10 worth of electricity over 12 months.

At the other end of the scale, set-top boxes and some multi-function printers use significantly more standby power.

In the case of multi-function printers, the power used on standby varies from nothing at all to more than $10 every month across different models.

Set-top television decoders were found to use almost as much power on standby as they did while in use and could cost $53.75 each year, even if the TV was never turned on.

With around 30% of the energy used by the average household flowing into hot water, reducing the time spent under the shower is a great way to cut costs, according to Powerswitch manager Paul Fuge​.

Every five minutes spent under the shower costs 33c so by cutting daily showers from 10 minutes to five minutes, a family of four could save $450 a year.

Consumer NZ test results show that washing your clothes in cold water is significantly lower in cost than running a warm wash, le Page said.

A cold wash in a front or top loader costs 3c to 8c per load, while a warm wash costs 13c to 46c .

One warm wash a day at 46c per load would cost $167.90 each year. A daily cold wash at 8c per load would cost just $29.20.

Research shows hand-washing the dishes actually uses more hot water than running the dishwasher.

A 2011 study done at the University of Bonn, in Germany, found households without a dishwasher used on average more than twice as much water to clean dishes as those with one.

The research was backed up by Consumer NZ's own testing which showed the average dishwasher used 13.5 litres to clean a full load.

“In comparison, our test sink at two-thirds full holds 13L,” product test writer Erin Bennett​ said.

"To wash as many dishes as a full dishwasher, you’d need to run at least three sinks (39L), including pre-rinsing.”

Rinsing suds off the dishes added another sink full of water and even more would be used if rinsing under a running tap.

“Although our testing shows generally dishwashers are more water efficient, there are multiple variations of hand-washing, so it’s important to think about how many litres of water you personally use,” Bennett said.

If you have an outdoor washing line, le Page recommends using it. However, drying clothes inside on a clothes horse isn’t recommended, as moisture accumulating indoors can lead to damp and mould growth.

“If you are opting for a dryer, especially in winter when drying outside isn't idea, heat pump dryers use the least electricity,” le Page said.

“You can check whether your electricity plan has cheaper periods, so you can save a few cents per load when using the dryer – some plans offer reduced off-peak rates or even free power for a short period each day. Make sure you're not paying a premium to dry your clothes at peak times.”