This is the definitive guide on the best temperature for washing your laundry.
The best temperature is actually highly variable.
There is no one size fits all when it comes to the optimal temperature for washing laundry.
The optimal temperature depends on a number of factors.
Level of soiling
With more heavily soiled garments, such as underwear and workwear, you may wish to use higher temperatures to help remove soiling more easily.
The higher temperature helps chemicals in your detergent work more efficiently, which helps break down soiling at a faster rate.
According to a study [1], a minimum of 40°C is required to properly inactivate pathogens.
That said, there are some pathogens that can be killed in cold water, which leads us to…
Type of detergent
The use of detergent can greatly enhance the effectiveness of your washing cycle.
Typically, the higher the heat, the more effective your detergent becomes, however, some detergents are still able to sanitise and break down soiling in cold water.
According to this study [1], washing with detergent that included Activated Oxygen Bleach saw improved hygiene outcomes, even in low temperatures.
If higher temperature washes are not an option, then extending the length of the wash can help give your detergent more time to break down soiling.
This can be especially helpful when using detergents that contain enzymes, which are typically used when soiling might include sweat, blood, and food, for example.
Colours
When it comes to dark and brightly coloured clothing, it’s best to ease up on the temperature.
One study [2] found increased evidence of colour loss, and colour transfer when washing clothes at 40°C and higher.
This means if you’re ever washing loads with strong colours, more so when washing a mixture of coloured and lights, you can help avoid discolouration by choosing a shorter washing cycle, with a lower temperature.
Materials
Different textiles can only be washed below certain temperatures before risking degradation.
Delicate fabrics should be washed in cold water. These garments can be made of materials including silk, lace, wool, and linen, to name a few.
Hardier fabrics, such as cotton, can be washed at higher temperatures, such as 30-40°C.
When in doubt, check the care instructions on the particular garment.
Final recommendations
When it comes to more heavily soiled laundry, we recommend washing in temperatures of at least 40°C to help reduce the presence of pathogens.
With regular or lightly soiled clothing, we recommend washing in cold water, to maximise the longevity of the garments.
Referenced studies
[1] https://ami-journals.onlinelibrary.wiley.com/doi/10.1111/jam.12647
[2] https://www.sciencedirect.com/science/article/abs/pii/S0143720819320431