Hot water vs cold water

Hot water is the most effective way to remove soiling. Nappies are heavily soiled laundry, if soiling is not removed it will lead to smells and stains.

All laundry detergents can be used in cold (30°C), warm (40°C) or hot (60°C) water, however, a hot wash will outperform every time. While cold washing saves money on energy costs, the downside is eventually smells will occur. Lower washing temperatures result in higher microbial levels in the washing machine and laundry. A higher level of microbes means more smells.

After extensive testing by our Clean Cloth Nappies Admin team and feedback from members, we can state with certainty that washing cloth nappies in cold water does not work in the long term. Nappies will not come out clean, smell and stain-free out of the wash, if washed in cold water in the longer term.

What do we mean when we say clean? They should come out of the washing machine after main wash as clean as they were when they were new.

Frequently asked questions (FAQs)

Why is hot water more effective at removing soiling and stains?

Heat breaks the chemical bonds of the soiling and stains, which means textiles are going to be cleaned better in hot water. This applies to all fabrics which are not heat sensitive (for example, cotton, bamboo/viscose, hemp, rayon, polyester).

The elevated temperature helps the raw materials in the detergent work. Sodium percarbonate (oxygen bleach) needs warm-hot water to work.

Do enzymes denature and stop working above a certain temperature?

They do. However, heat is far more effective at breaking the chemical bonds of soiling than enzymes are!

Why were enzymes added to detergents?

So that laundry could be washed at lower temperatures, i.e. 40°C or even 30°C.

What temperature should I use to wash my cloth nappies?

We recommend washing nappies in at least 40°C. Ideally cloth nappies should be washed at 60°C as this is more effective at preventing smells, stains and ammonia.

What temperature should I wash the rest of my laundry?

Whatever temperature suits your circumstances and the type of fabric. Bed linen, towels, clothing or items covered in food, dirt, etc, will come out of the machine much cleaner at 40-60°C.

Darks and coloured clothing may start fading over time at 60°C, so 40°C is a better option for these items.

Delicates and woollens should be washed at lower temperatures.

What if I don’t have hot water available?

Don’t worry! Modern Front Loader machines heat their own water. Traditional Top Loaders or High Efficiency Top Loaders require a hot water tap connection. If a hot water source is not available for a Top Loader, an option is to do a cold pre wash cycle, then bucketing in warm/hot water into the machine for the main wash.

Alternatively, sanitising with chlorine bleach will oxidise ammonia and kill any remaining bacteria.

References

  1. Textile Quality Depletion due to Household Machine Wash – Ways to Measure and Impacts of Wash Duration and Temperature on Textiles.
  2. Marlitt Honisch, Britta Brands, Mirko Weide, Horst-Dieter Speckmann, Rainer Stamminger and Dirk P. Bockmühl, Antimicrobial Efficacy of Laundry Detergents with Regard to Time and Temperature in Domestic Washing Machines.
  3. Dr Chemical, The Chemistry of Clothes Washing #8: Hot or Cold <https://www.drchemical.com.au/chemistry-at-home/laundry/the-chemistry-of-clothes-washing-8-hot-or-cold>.