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How to Pick the Right Washing Machine Size

Potential Savings*
10-Year $ Savings:
10-Year CO2 Savings:
399 kg (equal to driving a car 2,700 km)1
10-Year Water Savings:
63,544 litres (equal to 2.5 years of showers for a person)2
What to do:
Run a small number of full loads each week, instead of a large number of small loads.
*Savings are based on examples used in this article

washing machine fully loaded

Once you’ve decided whether to go for a front load or top load washing machine, you’ll need to think about what size you’d want.

Washing machine sizes are expressed in kg, which refers to the approximate load that you can fit into the drum of the machine. Sizes range from around 5kg – 7kg (small), 7.5kg – 8.5kg (medium) and 9kg + (large).

What’s the Right Washing Machine Size?

The right washing machine size is a size at which you can confidently run a full load in each wash. Your machine is at its most energy-efficient when it’s running a full load. Based on that principle, any number of sizes could be right for you. In the end it all comes down to your individual washing demands and habits.

What to Think About When Picking a Size

1. How big is your household?

For a family of four, a medium size washing machine (around 7.5 to 8.5 kg) should normally be enough. That’s the equivalent of around 35 T-Shirts per wash. If you’ve got a small household (1-2 adults), then a small washing machine (around 5kg-7kg) could be enough.

Remember that washing machines generally last a while – for 10 years or more in many cases. If you’re planning to have kids over that period you’ll need to account for the extra load you’ll face in the coming years. The last thing you want to do is have to buy a new washing machine at a time when you’ll have a lot of other expenses too.

2. How often do you wash your clothes?

Some people need to run a wash cycle daily, while others are happy to accumulate unwashed clothes for a few days before running a wash cycle. If you need to run a small load daily, then go for the smallest washing machine that can handle your daily load. If you accumulate clothes to do a “big wash”, then you could look at buying a larger size machine that you use less frequently.

3. How Do You Dry Your Clothes?

If you’ve got a lot of drying space – using a big backyard clothesline or a large drying rack for example – then you can afford to have a big washing machine. However if your drying space is limited then you’ll need to go for a smaller size machine. Otherwise your clothes could get smelly after sitting in your washing machine for days.

4. Separating Colours and Whites

If you run separate loads for coloured items and whites, then a smaller washing machine is best. That’s because most households can never accumulate enough whites to make a full load, or enough colours to make a full load. Research has shown that the average wash cycle in a 6-7kg machine is only 2.8kg,3 with separation of colours and whites being one of the main reasons. If on the other hand, you combine colours and whites in the same load, then you could probably run a larger machine efficiently.

5. How many clothes do you have?

If you’ve got a small quantity of clothes that you wear regularly, then chances are you’ll be running regular wash cycles, to make sure you’ve always got something to wear. In that case, you should go with a smaller washing machine. If you’ve got enough clothes to last you for most of the week, then you could run less frequent loads in a larger machine.

6. How heavy are your wash items?

The “kg” in the washing machine capacity is based largely on the volume of cotton T-shirts you could fit into your machine. It doesn’t take into account that we also put very heavy items such bath towels, jeans, jumpers and bed linen into our washing machines. If you frequently wash heavy items, then you’ll need a washing machine big enough to fit these without having to run multiple cycles.

Savings from Running a Full Load

Waiting to accumulate a full load before you run a wash isn’t as convenient as running a wash whenever you want. However can the cost and environmental savings make it worth your while?

We measured the difference in water and energy use between running a 7.5kg front load washing machine on cold water at full load, versus running the same machine at 2/3 capacity. We assumed a weekly wash load of 30kg, with both loads running on the same wash programme.

What We Found

Full Load 2/3 Load Savings
10 Year Energy Cost $183 $275 $92
10 Year Water Cost $306 $459 $153
10 Year Total Costs $489 $734 $245
10 Year CO2 Emissions 798 kg 1,197 kg 399 kg
10 Year Water Use 127,088
Table 1: Savings from running a washing machine at full load instead of 2/3 load. Volume of washing is equal to 4 full loads per week.

The inconvenience of waiting for the washing basket to fill up was worth an extra $245 over 10 years. It might not seem like much, but it is once you add the environmental benefits. You’d have saved 399 kg of CO2 – the equivalent of driving 2,700 km in a car. However the biggest saving was in water. You’d have saved a massive 63,544 litres of water – that’s the equivalent of two and a half years worth of showers2 for a person!

1. Based on a car emitting 150 g of CO2 per km.
2. Based on one 10-minute shower per day using a 3-star rated showerhead with a flow rate of 7L/min.
3. Electrolux and Proctor and Gamble, “Why size isn’t everything when it comes to washing machines!, 15 January 2010.”

© 2018 Start Sustainable Pty Ltd.