Custom kettle stickers: Saving water & energy, one cup of tea at a time

What unsustainable behavior needs to change:

Whether it’s for a cup of tea, coffee, or to fill a pot, chances are you’re using a water kettle multiple times a day. Yet, how often do you pour precisely the required amount of water into your kettle? It’s rarely accurate, often resulting in an overfilled kettle, wasted water and electricity. So, how might one reduce unnecessary water and energy use while preparing your daily hot water fix?

This seemingly minor issue is more serious than you think. Even in a country as tiny as the Netherlands, over 5.3 million cups of tea are brewed daily on average, leading to a considerable waste of water and electricity. Just to put it in perspective: boiling a litre of water consumes as much energy as keeping a light on for an entire day! Quite wasteful, isn’t it?

The Green Nudge:

To address that issue, behavioural agency, “Unravel Behaviour” devised a Green Nudge to encourage the precise amount of water required in the kettle: stickers that guide and personalise tea cup volumes.

Quantity charts on most kettles range from 1.5 to 2 litres; leaving out the precise millilitre measurement for a cup of tea. To ensure more accurate water usage, the experiment used a custom kettle sticker appliqué, specifically tailored to the volume of one’s favourite tea cup as the variable; and had one without – to serve as the control. This created nearly two identical kettles, differing only in the placement of the stickers. 

The result: Compared to the standard kettles, the stickered kettles showed 195 ml  of unused water remaining in the kettle. This means an extra glass of water, on average, was wasted in every tea-making attempt without the customised stickers. The translation of this impact: The nudge led to substantial energy savings and 1 glass of water, less wasted per person. Just in the Netherlands alone, overall, this totals 97 litres per individual, and a staggering 1.4 billion litres saved annually.