Washing at 30 degrees

There’s been a lot of talk about washing at 30 degrees in order to save energy costs but there are some things you should know before jumping on this particular bandwagon. Washing machine manufacturers are creating 30 degree wash cycles, and detergent manufacturers are making making attractive claims about how much money you can save, such as in the following quote -

Save “on average, an astounding 41% on energy consumption”

Using 41% less electricity by washing at 30° sounds impressive, but as always with percentage figures, you need some perspective to be able to judge how useful they are. For example, 2p is 100% more than 1p, but 1 pence is hardly astounding. High percentage figures aren’t necessarily as significant as they can imply.

In the small print of the Ariel wash at 30 degrees promotion there is the qualifier I’m looking for -

“At 30°C, the average energy consumed per wash was 0.284 KWh, while at people’s normal wash temperatures, this was 0.482 KWh”

This means the saving in electricity by washing at 30 degrees was on average 0.198 KWh. The current cost of electricity varies quite a lot depending on your current tariff, but the electricity cost calculator on the UK Power site (at time of writing) is shown at 10 pence per KWh (10p for using 1000 watts usage in an hour).

This means if you save 0.198 KWh you will have saved roughly 2 pence. The average energy costs used in the test for normal washing is 0.482 KWh which is just under half a KWh (5 pence) Therefore the 41% saving is only on this 5 pence, which works out at about 2 pence. (all figures are approximate and some people may be paying more per KWh, but even at 15p the savings would still only about 3p)

It all adds up?

Fair enough, any saving is good, and small savings add up. I’m just pointing out that the savings headline of 41% is slightly misleading, and that dropping to 30 degree wash temperatures from 40 degrees is not going to save a fortune. My concerns are that that even if these 2 pence savings eventually add up to something you’d care about they can easily be more than wiped out by the potential disadvantages listed later on. However, if enough people do it, then the accumulated savings nationwide are far more impressive. It would do another small bit for the environment – and the government’s carbon reduction targets.

Is your washing machine able to wash effectively at 30 degrees?

Before trying 30 degree washes for “normal” washing you need to check your washing machine. Most washing machines will have a 30 degree wash programme but it’s not necessarily suitable for washing cottons, especially if not modern. Many programmes were designed before 30° wash detergents came out, when only delicate laundry needed such a cool wash. As such, the wash action could be too gentle, and the spin too slow for cottons.

Washing machines are becoming available that do have a proper 30 degrees wash programme but many people do not yet have them. If you are going to buy a new washing machine and you want to wash many items at 30 degrees you need to check that is capable of washing normally at this low temperature and doesn’t just have a 30 degree wash for delicates.

Check the instruction book on your current washing machine to see if a proper 30 degree wash programme is available. Check what types of laundry it is designed for and what spin speed the final spin is before deciding it is suitable for general 30 degree washes. Of course it may still be suitable for washing delicate items at 30 degrees.

A workaround: Manual temperature override option

If your washing machine has a manual override option for temperatures then you should be able to select a normal cottons wash and just reduce the temperature manually to 30 degrees. This should result in a wash action appropriate for cottons with a proper fast spin at the end.

Finally, 30 degree washes have their limitations: Guide to washing at 30°C

1. You need to wash laundry that’s stained as soon as possible. If you let the stain dry out it may not be removed with only a 30 degree wash
2. You still need to wash coloureds and whites separately
3. If laundry is heavily stained you will need to wash it at the normal temperature, especially those with dried-on, strongly-coloured food, thick grease, heavy mud and grass stains. Otherwise you could waste energy by having to wash them again
4. If anyone in the house has been ill you should wash their laundry at the normal temperature i.e the maximum temperature allowed on the wash care label to try and kill germs
5. Washing a small load at 30 degrees is more wasteful than washing a full load at 40 degrees. In other words, if there are only a handful of items that can be effectively washed at 30 degrees and you can’t save them up until you have a full load then you might as well just mix them in with a normal load at 40 degrees
6. Conversely, if you have a large load that can be washed at 30 don’t overload it. Overloading reduces the wash efficiency at the best of times and this effect is worse at 30 degrees. You could end up having to rewash things again
7. Don’t be tempted to try and save money by reducing the amount of detergent used as this can result in long term build up of slime, grease and bacteria. Again, this is already a problem for people washing mostly at 40 degrees and will be worse at 30
8. Extra Important: If you use mostly liquid detergent, detergent “friendly to coloureds”, or wash mostly at 40 degrees or less, you should do regular maintenance washes at high temperatures. Otherwise over time, your washing machine may accumulate bacteria, mould and greasy smelly gunge inside which will shorten its life. Full details in my Washerhelp article – Washing machine smells – causes of grease, slime and black mould inside washing machines
9. The last point of course is likely to use up most or all of the energy saved by washing at 30 degrees, which is why I’m not convinced of it being such a great idea. If you have to use boil washes to prevent serious slime and grease build up, and/or the washer breaks down or doesn’t last as long because it gets bacteria, black mould and grease rotting it then it’s counter-productive

The list above uses some of the information available at Unilever, which I found during my research.

Which is the best detergent for washing at 30 degrees?

Which? Best Buy latest tests suggest

1. Ariel Excel Gel
2. Persil Small and Mighty Bio
3. Persil Small and Mighty Non Bio

Source Laundry detergent – Best buys & Reviews (research all consumer related issues: 1 month trial offer available at Which? – What do I get when I take a £1 trial? (Washerhelp.co.uk review) )