Many of us who are of a certain age will remember television commercials telling us to wash our clothes at 40 °C instead of 60 °C, in order to save energy.
These days even washing at 40 °C is often seen as wasteful, and 30 °C has become the default – with biological washing powders designed to work at these lower temperatures.
But is it always better to wash at a temperature not much higher than the air in the room? Surprisingly, there are several very compelling reasons to use 30 °C as your default, and only consider raising the heat in certain circumstances:
- Cost. As the adverts say, washing at a lower temperature saves energy, and that means it saves you money too. Washing machines typically heat the water themselves, so even if you have a hot water storage tank, washing on a cooler cycle should still save you money.
- Carbon. Saving energy isn’t just good for your wallet; it’s also good for your carbon footprint, so reducing the temperature you wash at should have positive implications for the environment. Ultimately, it is large numbers of people adopting small lifestyle changes like this that has the biggest chance of cutting the nation’s overall carbon footprint too.
- Quick. Many modern washing machines won’t allow you to select a temperature higher than 30C for the fast (often called the ‘economy’ or ‘everyday’) cycle. Even on other cycles, try changing the temperature setting and watch the effect on the estimated time – hotter takes longer, it’s that simple.
- Kind. Fabrics usually don’t enjoy being boil-washed, so unless your clothes are stained or heavily soiled, a quick wash on a low temperature might be all that’s needed to refresh the fibres and put some pleasant aromas into them from your chosen detergent.
Of course there are always downsides, and washing at 30 °C won’t always be ideal – particularly if you have stubborn stains to shift.
Biological washing powders didn’t have the best of starts either, as some slightly strong formulations ate away at natural fibres like wool and cotton, and not just the stains that clung to them.
These days, detergents are much more carefully formulated, but if you’re trying to shift sweat marks, blood or other organic stains, a higher temperature is the natural way to denature the enzymes and break down the visible marks.
Simply increasing the temperature is still not necessarily the right solution though – and it can often be just as effective to pre-treat white fabrics with bleach, and coloured materials with specific stain removers.
You might be reluctant to expose your clothes to harsh chemicals, or to allow such substances into the waste water released from your home or business, but on balance it might be the best thing to do.
Ultimately it is by selecting the best option – a higher temperature, a longer wash cycle, or a different combination of detergents – that we can all make sure our laundry cycles are as effective and efficient as possible.