Supporting evidence for 2023 winter energy savings campaign

Check your power plan

You might be surprised how much money you can save by simply changing your power plan or company. Households can typically save between $300 and $400 per year when they change plan.

Supporting Evidence:

The potential savings figure for changing to a cheaper power plan is $385. This is based on the median potential savings shown to users on the site.

CNZ analysed the results pages of around 46,000 Powerswitch users over winter 2022 (over the three-month period from 1 June through to 31 August 2022). The median saving by changing power provider or plan was $385 per annum.

CNZ repeats the same calculation each year. Over the last three winters the median savings have ranged from $310 to $388 per annum.

Get the most out of your heat pump

Heat pumps work best when set between 19 and 21 degrees. If it’s cold out, you don’t need to crank the heat pump to 30 degrees to make it work faster. High temperature settings use a lot of power and lead to an eye-watering power bill. To get the most out of your heat pump, change the mode on the controller so it’s on heat – click “mode” until the little sun icon shows on the screen. From there, set the temperature between 19 and 21 degrees. Save $320 per year.

Supporting Evidence:

The average running costs of heat pumps in the CNZ database (304 models) is $644 (assumes 1500 hours per year).

A 50% increase in running costs from 19°C to 30°C gives $966. So, a saving of $322.

This is a conservative figure; a lower set temperature means the heat pump will quickly reach temperature and then cycle on and off to maintain it. Higher temperatures will mean it’ll run continuously to try reach an unrealistic room temperature.

Using https://ecoplus.ie/heat-pump-kwh-cost-calculator/ - an increase of set temperature from 19°C to 23°C yielded an increase of in running costs of 44.65% using our figures.

https://www.ecodesignadvisor.org.nz/resources/heat-pumps-run-effectively/ indicates that a heat pump will use 50% more power when set at 26°C as compared to 21°C.

https://www.eeca.govt.nz/about/news-and-corporate/news/make-your-heat-pump-work-smarter-not-harder/ states “the higher the temperature, the more energy the heat pump will use.

Use the right heater in the right room

Different types of plug-in heaters typically all cost the same to run – around 50¢ an hour. However, they don’t all deliver heat in the same way and some are better suited to certain rooms over others.

Supporting Evidence:

Heater running costs from CNZ: https://www.consumer.org.nz/articles/appliance-running-costs#heating.

Know your power-hungry appliances

Most of the things that you have plugged in at home use power all the time, even when they’re not switched on. Switching off these appliances at the wall when not in use can save up to $100 on your power bill over the course of a year.

Supporting Evidence:

Multiple sources quote $100 savings (or more).

BRANZ ($100 per year): “By some estimates, standby power costs an average household around $100 each year. Gaming consoles, printers and wireless routers are among devices with the highest standby power consumption”. https://www.level.org.nz/energy/appliances/standby-mode/.

Northpower: ($250 per year) estimates are based on a 24 hour average rate of 35 cents per kilowatt hour https://northpower.com/electricity/advisory/standby-power.
Contact ($100 a year): https://contact.co.nz/thewire/lifestyle/7-tips-to-save-cash.
Energy Mate ($100 a year): https://www.energymate.nz/your-electricity.
Consumer NZ: https://www.consumer.org.nz/articles/appliance-running-costs.

Oven:

Cooking a large meal in the oven for the whole whānau will cost about $1 each time.

Supporting Evidence:

It takes around 3.25 units of electricity to cook a roast meal: https://ask.trustpower.co.nz/app/answers/detail/a_id/364/~/guide-for-the-running-cost-of-appliances. At the latest average CNZ representative unit price of electricity (25.4c/kWh) that would be 82.6c. Using the latest QSDEP average price for NZ (32.9c) that would be $1.07.

Slow cooker

You can save even more by getting the slow cooker out instead; it’ll cost about 35¢ a meal and you can use cheaper cuts of meat – win-win!

Supporting Evidence:

It takes around 1.25 units of electricity to cook meal in a slow cooker: https://ask.trustpower.co.nz/app/answers/detail/a_id/364/~/guide-for-the-running-cost-of-appliances.

At the latest average CNZ representative unit price of electricity (25.4c/kWh) that would be 31.75c. Using the latest QSDEP average price for NZ (32.9c) that would be 41.13c.

Lights

An old 100W lightbulb will cost you about 20¢ each evening to run. This all adds up, so be sure to turn lights off when you’re not in the room. If you can get your hands on them, opt for LED lightbulbs as they’ll pay for themselves in power savings very quickly – the 100W equivalent LED bulb will only cost 3¢ over an evening which could save you $62 a year.

Supporting Evidence:

EECA: “LED light bulbs use up to 85% less electricity than traditional incandescent or halogen bulbs and can last 15 times longer”. https://genless.govt.nz/for-everyone/at-home/use-led-lighting/#:~:text=LED%20light%20bulbs%20use%20up,can%20last%2015%20times%20longer.

Assume the light is on for six hours. 100W for 6 hours = 0.6kWh x 25.4c (CNZ average representative price) = 15.24c. QSDEP: 0.6 x 32.9c = 19.74c.

If LEDs use 85% less energy that translates to 2.29c at the representative price and 2.96c at the QSDEP, for the same period.

EECA: “A typical New Zealand household could save between $100 and $150 a year on its power bill by switching to LED lightbulbs” https://www.stuff.co.nz/business/102915271/switching-to-led-lightbulbs-saves-at-least-100-a-year-eeca.

Heated towel rail

A warm fluffy towel feels lovely after a shower. But did you know that leaving a heated towel rail on will cost you about $3 per week? Switch it off and save yourself around $140 on your yearly power bill.

Supporting Evidence:

Assume towel rail on for 47 weeks of the year. $3 x 47 weeks = $141. Or $156 if left on for the entire year.

EECA: “A heated towel rail left on 24/7 can cost you $170 per year to run” . https://www.eeca.govt.nz/about/news-and-corporate/news/tips-for-the-cold-winter-nights/

An 80W heated towel rail left on 24/7 =1.9kWh consumption per day. 1.9 x 25.4 = 48.26c per day (representative price) and 1.9 x 32.9c = 62.51c (QSDEP). Over a week that’s $3.38 per week (Rep price) or $4.37 per week (QSDEP). Over a year: $175.76 (Rep price) or $227.24 (QSDEP)

Drying clothes:

A regular vented clothes dryer costs about $1 per load. It might be your only option during wet, cold weeks but take advantage of drying clothes outside as much as possible – it’s free after all.

Supporting Evidence:

CNZ appliance running costs: https://www.consumer.org.nz/articles/appliance-running-costs#laundry range = 86c (3.5 kg load) to 1.06c (5kg) per load. EECA: “…an average load costs around $1” https://www.stuff.co.nz/life-style/homed/latest/104203206/how-much-does-it-cost-to-put-a-load-of-washing-through-the-dryer.

Reduce your hot water usage

Did you know that hot water makes up about a third of your power bill in winter? That’s a huge chunk of money! However, a few simple changes can help you make some big savings here. Let’s have a look at a few.

Supporting Evidence:

BRANZ studies and EECA data states that around 30% of a home’s energy use is for hot water.

• 29% from BRANZ HEEP Study: https://d39d3mj7qio96p.cloudfront.net/media/documents/SR155_Energy_use_in_NZ_households_-_report_on_year_10_of_the_Household_Energy.pdf.
• EECA Energy End use database: https://www.eeca.govt.nz/insights/data-tools/energy-end-use-database/.

Showers

The more hot water you use, the more you’ll pay. Each 15-minute shower will cost you about $1 – think about how many people you have in your house, and it’ll give you an idea of how much it’s costing you per day. If you can shorten the showers down to five minutes, you’ll save 66¢ each time. That’s an average of $5 per person per week.

Taking a nice hot bubble bath in winter feels like pure bliss. Unfortunately, it costs about twice as much as a shower each time. Keep baths to a minimum and make sure the shower is the first option.

Shorten your showers to five minutes – save $260 per person.

Supporting Evidence:

• If you save around 66c by reducing shower time from 15 minutes ($1) to 5 minutes (33c). $1 - $0.33 = $0.67. One shower per day = 7 x $0.67 = $4.69 per week in savings. That’s $243.88 per year per person.

• From Stats NZ: The average number of people per New Zealand household is 2.7 people, which has remained unchanged since 2006. So average savings per household through reducing shower time from 15 to 5 minutes is 2.7 x $243.88 = $658.48

• EECA: ‘’Reducing your shower time just a bit could save up to $900 a year for a family of four. A 15-minute shower costs about $1 - a 5- minute shower costs about 33c.” https://www.eeca.govt.nz/about/news-and-corporate/news/keep-your-energy-bills-down-during-lockdown/ · Also, Energy Mate: https://www.energymate.nz/your-electricity “Long showers can add up quickly, costing you hundreds of dollars a year. A family of four can save $10 a week by cutting five minutes off their showers.” That $520 per year.

• Being more conservative and reducing from assumed 10 minutes to 5-minute showers (ie halving the savings to 33c per shower):

  • $2.31c per week per person in savings. That’s $120.12 per person per year.
    • 4 person household = $480.48 per year in savings
    • § 2.7 person household (NZ average) = $324.32 per year.

• Shower (10 minutes) uses 3.75 units of electricy. https://ask.trustpower.co.nz/app/answers/detail/a_id/364/~/guide-for-the-running-cost-of-appliances Cost: 3.75 x 0.254c (CNZ rep price) = 95.2c. And 3.75 x 0.329c (QSDEP) = $1.23.

• Bath: use up to 7 units of electricity. Cost: 7 x 0.254 = $1.78c (CNZ rep price) and 7 x 0.329 = $2.30c. So roughly double the cost of a shower.

Stop the drips

A dripping hot tap can waste more than 70 litres of water a day. This can add over $200 a year to your power bill! If you are renting, notify your landlord as soon as you notice a drip – fixing a tap that’s dripping from normal wear-and-tear is usually their responsibility.

Supporting Evidence:

CNZ: https://www.consumer.org.nz/articles/plumbing-and-drainage#:~:text=Dripping%20taps,-Dripping%20taps%20or&text=If%20it's%20a%20hot%20tap,to%20re%2Dseat%20the%20tap.

Cold laundry wash

Putting on a warm wash will set you back about 30¢. A cold wash often performs just as well and only costs 6¢ per wash. A whānau with children and endless washing can make some savings here – approximately $50 per year in fact, if your family does about four laundry washes per week.

Supporting Evidence:

CNZ appliance running costs: medium top loader assumed: https://www.consumer.org.nz/articles/appliance-running-costs#laundry.

Saving = 24c per load. Assume one load per day = 365 x 0.24c = $87.60.

EECA: “A hot water wash can use 10 times more electricity than a cold wash.” https://www.eeca.govt.nz/about/news-and-corporate/news/keep-your-energy-bills-down-during-lockdown/.

Energy Mate: “Using cold water could save you around $80 a year”. https://www.energymate.nz/your-electricity.