A smiley face isn’t just a friendly way to sign off a text message – it can also be a powerful tool to make people save more energy.

So suggests a new study into emoticons which tested 462 homes from fourteen associations around England (all with smart meters installed).

The Sustainable Homes group compared the energy use of homes without any feedback on their energy use with a “smiley” group.

These 110 homes were rated with a “very happy” face if they were in the top 25% lowest energy users for homes of a similar size.

The rest were shown either a smiley, neutral or sad face depending on their performance.

The findings showed an average of 8% could be saved on the electricity bill and 3.6% saved on gas with emoticon-style feedback.

This could mean a saving of £79 for an average household each year (16,500 kWh/yr gas and 3,300 units electricity).

According to the report, “It shows people are responsive to messages about how they compare to others, which appeals to their intrinsic values and helps them save energy not simply because of the money it will save them.”

The study builds on previous work from Opower and comes ahead of the UK’s nationwide rollout of smart meters which will collect data about homes energy use.