There are four factors to achieving clean laundry:
- time
- temperature
- chemistry (detergent, stain removers)
- mechanical action (loading)
This model was first proposed by Herbert Sinner in 1960 and is also known as Sinner’s Circle. The factors work together and learning to adjust them will influence how clean your laundry is.
The four factors
Time
Time refers to the length of the wash cycle. Increasing the duration of the wash cycle means items will come out cleaner because the contact time for friction, which removes physical soiling, also increases.
If you need to increase cycle length, increase the contact time with detergent, rather than adding extra rinses.
Temperature
Washing in warm to hot (40–60°C or 100–140°F) water is the most effective way to get your laundry clean. When the temperature of the water increases, the heat breaks the chemical bonds of the soiling and stains more easily, which means your laundry is going to come out of the machine cleaner.
However, it is not always possible to increase your wash temperature, especially when washing heat-sensitive materials such as wool and silk.
Chemistry
Laundry detergent is essential for cleaning heavily soiled items such as nappies. The different raw materials included in the detergent as well as the amount of detergent used will determine its effectiveness. It is important to choose an effective detergent, preferably with enzymes, and use enough of it to ensure clean laundry.
Sometimes items will still be stained when the wash cycle finishes, even when using the best detergent. Detergent alone often isn’t enough and you will need to add other stain removal products and techniques. Laundry boosters and chlorine bleach are useful for removing stains. Bar soap is useful for removing physical soiling (such as residual poo, mud or food).
| Product | In-wash | Cost | Soft water | Hard water | Sustainable1 |
| Bar soap | |||||
| Stain removal spray | |||||
| Laundry booster (oxygen bleach) | varies2 | ||||
| Chlorine bleach |
Mechanical action (loading)
Mechanical action helps to loosen particles of soiling from the fabric fibres, which makes them easier to remove. This is achieved through friction between laundry items in the machine as well as the turning, agitating motion of the washer drum.
Front loaders, traditional top loaders and high-efficiency (HE) top loaders operate differently and have different cycle lengths and loading requirements. Getting the right ratio of water to laundry is important for optimal cleaning. Irrespective of the machine, if there are too many items in there, they cannot move around freely. Too few items means there will not be enough friction.
While good loading helps remove soiling, it won’t necessarily remove all stains.
Note: soiling refers to dirt, sweat, bodily fluids or other contaminants left on fabric. Staining is an area of discolouration that may remain even after washing.
Getting the best results from your machine
Front loaders, traditional top loaders and high-efficiency (HE) top-loaders operate differently from each other. They all still rely on the four cleaning factors but in different proportions.
We provide machine-specific advice to help you make the most of your washing machine type:
How different machines work
It is important to consider each of the four cleaning factors in your laundry and adjust each of them until you achieve an optimal result.
Front-loaders heat their own water, rely on gravity for friction and have longer cycles. Because of this, front loaders are more effective at removing soiling and produce better results.
Top loaders don’t heat their own water. This means the wash temperature cannot get as high as in a front loader. Additionally, when the machine fills with heated water, the water cools as the cycle runs. Top loaders also have shorter cycles and rely more on water to aid in agitation.
Compared to front loaders, top loaders depend more on detergents and other stain removal products to achieve a great clean, although both machine types need additional stain removal methods to ensure stain-free laundry.
Ensuring a great clean
If items are not coming out clean, consider:
- Increasing the wash time
- Increasing the wash temperature
- Using more detergent, or adding additional stain removal products
- Adjusting your machine loading
Frequently asked questions (FAQs)
Some of your laundry-specific cleaning factor questions answered.
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?
Enzymes were added so that laundry could be washed at lower temperatures (for example 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.
With the rising costs of energy we know our members are looking at ways to reduce their hot water use. Using bleach in your prewash enables you to wash in cooler water.
Cold water is not as effective at removing stains. Be prepared to pretreat items with bar soap if washing in cold water.
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 or dirt 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?
Traditional Top Loaders and High Efficiency Top Loaders require a hot water tap connection. If there is no hot water available try a cold prewash cycle with chlorine bleach, then bucket in warm/hot water into the machine for main wash.
With the rising costs of energy we know our members are looking at ways to reduce their hot water use. Using bleach in your prewash enables you to wash in cooler water.
Cold water is not as effective at removing stains. Be prepared to pretreat items with bar soap if washing in cold water.