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Energy Efficiency Brochure Calculations

Calculations and Assumptions

Tips Yearly Savings*
Use natural warmth from the sun as much as possible to dry clothes instead of the dryer. SAVE $40* each year.
Washing powders are so effective in cold water these days, there’s really no need to do hot washes. SAVE $60* each year.
Got a beer fridge? Turn it on at the weekend and keep it switched off during the week. SAVE $100* each year.
Check that your hot water is no more than 55degrees C at the tap. Every 10 desgrees C higher than that, and you’re spending a hefty 10% more than you need to. SAVE $30* every year.
Like your towels warm and dry? Your heated towel rail can do the job in just a couple of hours - then flick it off. SAVE $100* each year.
Phase out standby mode altogether. Those innocent little red lights on your appliances are silent energy-guzzlers. And it’s not just the obvious culprits like TVs, stereos and electronic equipment. Washing machines, dryers, and phone chargers left on at the wall can also drain a lot of unnecessary energy. Switch EVERYTHING off at the wall and you’ll save $75* a year. SAVE $75* a year.

Ticked all the boxes? You just saved about $400 a year or $30 a month*. You’ve saved more than just money - you’ve saved enough energy to neutralise the CO2 emissions for return coach trips all the way from Cape Reinga to Bluff*.


Calculations

  • Total Savings - $400.
  • Total Carbon Emission Savings.
  • $400/$0.15 = 2666 kWhs.

  • 2666kWhs = 616kg of CO2.


Assumptions

CO2 emissions for a return coach trip from Cape Reinga to Bluff is approximately 152.48kg CO2. By implementing all the tips, this would neutralise the CO2 emissions of four return coach trips from Cape Reinga to Bluff.

  • Driving distance from Cape Reinga to Bluff (one way) = 2131kms - excludes ferry crossing.
  • Return distance = 4262kms.
  • Four return coach trips = 17,048kms.
  • 17,048kms scheduled coach trip = 609.92kg of CO2.

1. Replace main light bulbs with fluorescent ones.

Initial Investment: Around $20 for four bulbs*
You Save: $84 a year*
The Planet Saves: In a year this adds up to the same amount of CO2 as you would save by not using your car for six weeks.


Calculations

  • Average household energy savings: 466 kWh per year.
  • $0.18 (variable rate per kWh) = 466 kWh.
  • 466 kWh x $0.18 = $83.90 savings per year.
  • 0.979 kg/kWh (Marginal carbon factor) x 466 = 456kg of C02 per year.
  • This is equivalent to avoiding 1892 kms of car travel (at 0.241 kg CO2 per km for an average sized car).
  • 1893/320 = 5.9 weeks

Assumptions

  • $0.18 cents per kWh.
  • 0.979kg of CO2
  • Average kilometres travelled per week is approximately 320 kms.

2. Install a water-efficient shower head.

Initial Investment: $60 - $200
You Save: $120 a year*
The Planet Saves: This is equivalent to four return flights from Auckland to Wellington.


Calculations

  • Power savings 688 kWh
  • $0.18 (variable rate per kWh)
  • Cost savings $0.18 x 668 kWh = $120
  • Carbon savings 0.979 (Marginal carbon factor) x 668 = 653.55 kg CO2
  • Equivalent to four return flights from Auckland to Wellington, 495 km each way at 0.159 kgCO2/km.

Assumptions

  • $0.18 cents per kWh.
  • 0.979kg of CO2
  • Flying distance from Wellington to Auckland = 495.89 kms
  • Domestic flights emit 0.159kg of CO2 per km.

3. Install an instant gas hot water system, so you’re only heating water as you use it.

Initial Investment: $1,500 - $3,500
You Save: $214 a year* (provided you already have gas installed)
The Planet Saves: This avoids the same amount of CO2 as cutting back your household rubbish by 240 of 8kg bags a year.


Calculations

  • Power savings = 2143 kWh
  • Cost savings 2143 kWh x ($0.18 power cost minus $0.08 gas cost) = $214
  • Carbon savings (power) = 0.979 (marginal carbon factor) x 2143 = 2098 kg.
  • Carbon increase (gas) = 0.187 x 2143 kWh = 400.74 kg
  • Net carbon saving = 1697.26 kg
  • Equivalent to 1941 kg of Household waste to landfill (at 0.874 kg CO2/kg.

Assumptions

  • $0.08 per kWh for gas
  • 0.979kg of CO2 per kWh
  • Based of standard losses from electrical hot water systems this can vary depending upon grade of electrical hot water systems.
    COMMENT: Assumption seems vague, how big was water heater, how many people in the family? How long do they shower for?

4. Install a heat pump for healthy dry heat through your home.

Initial Investment: $2,500 - $4,500
You Save: $870 a year*
The Planet Saves: Almost enough to completely neutralise the CO2 emissions for one person flying from NZ to the UK and back.


Calculations

  • Power savings 4832 kWh.
  • $0.18 (variable electricity rate per kWh)
  • Cost savings = 4832 x $0.18 = $870
  • 0.979 (marginal carbon factor) x 4832 kWh = 4730 kg of CO2

Assumptions

  • Suggested annual savings are based on heating a well insulated area of 30m2 with a 2.4m stud for 10 hours per day during winter months (estimated at 26 weeks) and comparing an energy efficient Panasonic heat pump (model CS/CU-E12JKR with a 4.9 kW output operating at 100% and two electric oil column heaters with a combined output of 3.6 kW at 100%.
  • Because the heat pump produces more heat, it only needs to run for 7.5 hours per day.
  • Running costs estimates are based on the same daily HEAT output of 36.0 kWh with electricity prices calculated at 18.0 cents/kWh variable rate.
  • These are indicative only and should not be relied on for accuracy.
  • MFE guidance states the carbon emission factor for international travel as 0.132 kg/km.
  • It is 18331 km from Auckland to London, so a return trip is the equivalent of 4839 kg CO2.

5. Insulate your hot water cylinder (if it’s not an A grade cylinder).

Initial Investment: $100
You Save: $50 a year
The Planet Saves: This is enough to completely neutralise CO2 emissions for a return car trip from Auckland to Palmerston North.


Calculations

  • Power savings = 280 kWh
  • Cost savings 280 kWh x $0.18 (variable electricity cost) = $50.40
  • Carbon savings = 0.979 (marginal carbon factor) x 280 = 274 kg.
  • This is equivalent to avoiding 1137 km of car travel (at 0.241 kg CO2 per km for an average sized car).

Assumptions

  • $0.18 per kWh for electricity
  • 0.979kg of CO2 per kWh

6. Install insulation in your ceiling and under your floor.

Initial Investment: From $2,800 (based on 100m2 home)
You Save: $168 a year
The Planet Saves: This is enough to completely neutralise the CO2 emissions for 11 people flying from Auckland to Wellington.


Calculations

  • Power savings = 933 kWh
  • Cost savings 933 kWh x $0.18 (variable electricity cost) = $168
  • Carbon savings = 0.979 (marginal carbon factor) x 933 kWh = 913 kg.
  • This is equivalent to 11 one way flights from Auckland to Wellington. (495 km each way at 0.159 kgCO2/km)

Assumptions

  • $0.18 cents per kWh.
  • 0.979kg of CO2
  • Flying distance from Auckland to Wellington = 495.89 kms
  • Domestic flights emit 0.159kg of CO2 per km.

*These are indicative savings only.

Energy efficiency tips and savings approved by Energy Efficiency and Conservation Authority (see eeca.govt.nz). Greenhouse gas emission conversion factors subject to change.
Click here to view up to date carbon emission information.