Water usage volumes for washing machines

Calculate your washer’s water usage volume, or size in kilograms (kg), to use the bleach calculator exactly like our Australian and New Zealand counterparts! 

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| (updated )

Learn how to calculate your washer’s water consumption, or convert its size to kilograms (kg), to use the bleach calculator exactly like our Australian and New Zealand counterparts! 🙌

There are three ways to do this:

  • Calculating the average water consumption per cycle and converting this to litres
  • Calculating the annual water consumption and converting this to litres
  • Converting the washer size from cubic feet to kg

There may be slight differences between the calculations. If your washing machine is Energy Star certified, the preferred method is the average water use per cycle.

Calculating the average water used per cycle using the IWF equation

IWF is the quotient of the total weighted per-cycle water consumption for all wash cycles, QA, divided by the capacity of the clothes washer, C. The lower the value, the more water efficient the clothes washer is.

~ Energy Star website

Use the Energy Star Integrated Water Factor (IWF) equation to calculate the total weighted per-cycle water consumption.

  1. Search for your washer on the Energy Star product finder.
    • Both front loaders and top loaders are listed.
  2. Note the volume (cu. ft) and Integrated Water Factor (IWF).
  3. Multiply the volume by the IWF to find the average water used per cycle.
    • This figure is provided in gallons
  4. Multiply the gallons by 3.785 to convert to litres (L).

Example: LG – WM9500H*A

  • In this example the IWF = 2.7 and machine capacity = 5.8 cu ft
  • Water consumption per cycle = 2.7 × 5.8 = 15.66 gal
  • 15.66 gal multiplied by 3.785 = 59L

Calculating the average water used per cycle using the annual water use

Use the Energy Star website to find the annual water use, then convert that to the average water used per cycle.

Annual Water Use (gallons/yr) is the estimated annual water use of the washer under typical conditions. It is based on an annual usage of 295 loads per year, or around 6 loads per week, as referenced by the U.S. Department of Energy (DOE) test procedure, Code of Federal Regulations

~ Energy Star website
  • Search for your washer on the Energy Star product finder.
    • Both front loaders and top loaders are listed.
  • Note the Annual Water Use (gallons/ year).
  • Divide by 295 to find the average water use per cycle (gallons).
  • Multiply by 3.785 to convert to litres (L).

Example: LG – WM9500H*A

  • In this example the Annual Water Use is 4,588 gallons/ year
  • Water use per cycle = 4,588 gallons / 295 = 15.55 gal
  • 15.55 gal multiplied by 3.785 = 58.8L

Converting North American washing machines from cubic feet to kilograms

If your washer is not listed on the Energy Star website we have a rough (slightly scientific!) conversion to work out the approximate machine size in kg.

Converting washing machine capacity from cubic feet to kg involves estimating how much laundry (by weight) can fit into a given volume. The generally accepted standard is:

  • 1 cubic foot = 28.3L
  • 1 kilogram of laundry requires approximately 10 – 12L of space

Example for a 4.5 cu ft machine

Using 11L/ kg as an average, the conversion for a 4.5 cu ft machine is:

  1. 4.5 cu ft. * 28.3 = 127.35L
  2. 127.35L ÷ 11 = 11.6kg

If the calculations indicate your machine is larger than 11kg, use the 10.5-11kg option.