news article

BE REEL! Get energy out of your bill

Get energy out of your bill! (in Dutch: Haal energie uit je factuur) With that slogan, the city of Mechelen addressed all households to reduce their energy consumption and thus reduce CO2 emissions. But how do you do that? How can communication support the energy transition? And what motivational techniques can you use to convince Mechelen's people of this?

The study was preceded by extensive analysis (phase 1: 2018-2019). We delved into behavioural science and investigated exactly how influence works. What drives people to change their behaviour? We concluded that social comparison is an interesting approach to getting someone to look at their habits. In other words, 'How do others do it?' We decided that intelligent technologies should be deployed to track energy consumption and that precise language is central to our communication.

A comparative study revealed that energy suppliers who commit to less consumption achieve the most successful results. Therefore, the energy bill is the best tool for reaching everyone, even those who are not energy-conscious. Everyone receives their bill digitally or on paper, and it contains a lot of interesting information about their energy consumption. An extra plus is a financial win. Because who doesn't want a lower energy bill? 

We bent over the design in phase 2 (2020-2021). City of Mechelen, Veka, Fluvius and KU Leuven put their shoulders to the wheel. We brought different partners together to come up with the best behavioural insights. We decided to design leaflets and submitted the first design to 7 Mechelen citizens with diverse backgrounds. The different influencing principles from the preliminary research were given specific content. We worked with an incentive, compared our energy consumption with that of the neighbourhood, had Malinois testify, and so on. In this way, we could later examine the exact impact of these motivational techniques on energy consumption.

Research questions

But what exactly was measured? The research questions were as follows:

  • What and how significant is the effect after receiving the leaflet with comparative information on gas and electricity consumption?
  • Does how the consumption information is expressed (in euros, CO2 or a mix of both) play a role?
  • Do you think an incentive would work?
  • Is the possible effect different for vulnerable groups (social tariff) than for other Mechelen households?

Four seasonal leaflets were sent out for this survey. All Malines 36,600 households received information on the average consumption of gas and electricity and the consumption of the 20% most economical households in the neighbourhood. With this information, Mechelen residents could compare their energy consumption. The information on the leaflet also varied from neighbourhood to neighbourhood. Energy consumption could be expressed in euros, CO2 or a combination of both. Half of all neighbourhoods also received an incentive with each leaflet. This was a meter card in the first shipment to record your consumption. The second time, it included memo stickers with tips you could use at home. The winter edition included a radiator key with instructions and a heat loss map. And with the last spring leaflet, you found energy-saving cleaning and DIY tips. This created six different condition groups, randomly assigned across 90 distinct neighbourhoods. Everyone received their leaflet four times over a year, each time with new info, a testimonial, and seasonal tips to get started.  

Using consumption data from grid operator Fluvius, the city of Mechelen, in collaboration with the Catholic University of Leuven, analysed for two years whether or not the leaflets and incentives caused the energy consumption of Mechelen residents to go down compared to other Flemish cities. We also checked which motivation technique worked best and whether there was a lasting effect after completing the experimental phase.    What emerged: A 15.8% reduction in electricity consumption and a 25.9% reduction in gas consumption was measured. The decrease in electricity consumption was in line with the other reference cities (Aalst, Leuven, Sint-Niklaas and Kortrijk).  

But Mechelen households saved an average of 2.1% more gas in proportion. We cannot immediately give an unambiguous explanation for this. How the information was expressed (CO2, euro or a mix) did not affect consumption. Getting an incentive did not play a role either. And no difference was observed between higher and lower socio-economic status. We did see higher savings on average among large consumers.   But, the context in which the study was conducted also logically plays an important role. Indeed, a lot was going on during the survey and post-measurement. In October 2021, we faced historic gas and electricity price increases. In February 2022, war broke out in Ukraine, resulting in an unprecedented energy crisis. Energy suppliers, governments, poverty organisations, etc., all set up large-scale communication campaigns with tips to save energy and costs. Those events strongly influenced the research results. 


Leaflets work when combined with solid communication through clear, simple and intensely visual channels. It is also essential that governments and energy suppliers keep repeating that continuously. A price increase, logically, also makes people save. Steering people (nudging) can help complement an offer of structural measures. Incentives only work in the short term but are an excellent means of directing people toward information. What was unique about the study was that Mechelaars could compare their consumption with the 20% most frugal neighbours and similar family sizes, gain insight into their consumption and immediately receive tips to get started. This made a difference.  Why large consumers react more strongly requires additional research. And we must continue to focus on extra support for vulnerable target groups. 

We incorporate all these insights into the operation of the Mechelen Living and Energy Counter, one of 20 energy houses in Flanders. There, we are ready every day for every Mechelen inhabitant with info, advice, and guidance on all energy (saving) questions. We like to help our residents on their way with extra tips. They get information on how to measure their consumption and how to make their homes energy efficient. This is how to get energy out of your bill!

More information (in Dutch)