Washing at 30 degrees
There’s a lot of talk about reducing the wash temperature to 30 degrees but there are some things you should know before jumping on this particular bandwagon. This is the claim made by a leading washing machine detergent manufacturer -
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 significant 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 various 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 dropping to 30 degree wash temperatures from 40 degrees is not going to save a fortune. However, if enough people do it, then the accumulated savings nationwide are more impressive and it would do another small bit for the environment…
Is your washing machine able to wash effectively at 30 degrees?
Before trying 30 degree washes you need to check your washing machine. Most washing machines have preset programmes and many are not designed for 30° washing. Some washing machines do have a 30 degree wash programme but it’s not suitable for washing cottons. This is because these programmes were designed before 30° wash detergents when only delicate laundry needed such a cool wash. As such, the wash action is too gentle, and the spin is too slow for cottons.
Washing machines are becoming available that do have a proper 30 degrees wash programme but most 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.
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 reduce the temperature by hand 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
- 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
- You still need to wash coloureds and whites separately
- 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
- If anyone in the house has been ill you should wash their laundry at the normal temperature i.e the maximum tempeerature allowed on the wash care label
- 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
- 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
- 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 (see last point below for more details) 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
The list above uses some of the information available at Washing at 30 degrees (Unilever) which I found during my research.
Written By - Washerhelp on May 8th, 2008 with
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