Digitalization

Kredsløb, DK views its district heating customers as partners in the green transition. Therefore, this innovative district heating company has developed a data-based and automated solution for personal communication with customers. An internal experiment shows that targeted emails can motivate customers to improve their return temperature, leading to a smaller energy loss at the customer’s premises.

By Elsebeth Arendt, Head of District Heating, Kredsløb, DK

Published in Hot Cool, edition no. 3/2025 | ISSN 0904 9681 |

The future of green district heating in Aarhus, DK is mapped out. Kredsløb has a strategy in place for making the green district heating of the future happen. A plan that maps out the necessary technologies and heat sources. The path is clear, but one challenge remains – a challenge that is completely different: customer motivation.

District heating customers are primarily interested in whether they have a stable heat supply. As long as their home stays warm, they don’t give much thought to where the heat comes from or how efficiently it’s used. This situation can be problematic because the customers are not keeping up with green developments.

A green transition and the phasing in of new sustainable production units will only succeed if the customers’ own heating systems also keep up with developments. Therefore, the challenge is communicating with affected customers so that they should optimise their heating systems.

In Aarhus, there are approximately 375,000 citizens, and 95% of them heat their homes with district heating. Therefore, the number of potential customers that need to be reached is tremendously high. So, the big challenge is how to communicate with as many people as possible most effectively.

Kredsløb tries to meet the challenge by communicating differently and more purposefully, especially with the private district heating customers. The purpose is to get them interested in their heating system and take action if there are inefficient parts.

This challenge is solved using a data-based and automated solution that requires fewer human and financial resources than before, when customers were being contacted individually by email, letter, or phone.

30 district heating customers receive an automatically generated email every day

Every day, Kredsløb sends emails to 30 private district heating customers. The customers selected are those whose heating systems have the highest return temperature reported via the Sales Force system. The return temperature measures how efficiently a home uses district heating. Ideally, water should leave the system at 30-35°C, but many customers return it at 50°C or higher – wasting energy.

Customers qualify to receive an email by having a return temperature of over 50 degrees on average for three days or over 40 degrees on average for seven days. Those customers are targeted by the new automated communication process.

“The number of customers has been regulated according to how many Kredsløb’s staff can talk to them the next day. In addition to the customers who call every day with other questions, the customers who receive an automatically generated email often call the next day for technical help,” explains Lene Pedersen, the Head of Customer Service.

In the daily automatically generated email, 30 customers are informed that their heating systems can be made more efficient. Once the customer has received an email, they have 60 days to correct their return temperature before potentially receiving a follow-up email if their return temperature is again consistently too high.

In addition to the technical part of setting up a data-driven communication system that priorities customers daily, the content of the emails was subject to experiments as well. The challenge was to gain the customers’ attention.

“First of all, it was important for us to find out how to get district heating customers to open the emails we send to them. Because if they don’t even open the emails, it’s challenging to get them to change their behavior,” states project manager Christian Damsgaard.

“Your return temperature is higher than your neighbour’s.”

All companies compete with each other today to get customers’ attention, as they are often massively bombarded with information in their mailboxes. Kredsløb wanted an answer to how they could best capture the attention of their district heating customers.

How could they ensure that the customers open emails informing them about the high return temperature? Therefore, in November 2023, Kredsløb conducted an experiment, sending emails to 1,300 customers using three different messages.

The first message was about momentum and had a subject line in the email: “Now is the time to save on the heating bill.” The second message was about solidarity and had the subject line: “Do you want to help make Aarhus greener?”. The last message was about competition and had the subject line: “Your return temperature is higher than your neighbor’s.”

And the result was quite clear-cut.

“We perhaps had hoped rather than expected that the focus on solidarity would perform best. We want customers to get involved in the green transition. But the email customers opened the most was the one with the competition message, which is more specific to them,” elaborates Christian Damsgaard.

Message-specific emails can lower customers’ return temperature.

Of course, the test trials were also evaluated to see if the emails influenced the district heating customers to lower their return temperature, which is ultimately the goal. The results showed that the return temperature decreased significantly among the customers who received an email with a competition message compared to the control group.

On the other hand, the return temperature did not drop significantly for the customers who received emails with the other messages. The experiment proved one thing: the competitive message works best. Customers who received an email stating their return temperature was higher than their neighbors were significantly more likely to take action.

It seems customers do not quite like the idea of their neighbor’s system performing better than theirs. As it turns out, the old saying holds: the grass of your neighbor’s lawn always seems greener than your own – and in this case, so does the district heating system. Customers were far more likely to act when they saw their neighbor’s return temperature was lower than theirs.

“It’s interesting that it’s not just any email that has an effect. There is an effect if customers receive a specific email, namely the one with the competition message, which can help change the customer’s behavior. It shows that it is not only a technical project but also an organisational project about communicating with customers differently,” explains Christian Damsgaard.

Therefore, Kredsløb today uses the competition message when they send automated emails to district heating customers. And so far, it’s been working well.

“The automated process for sending out emails means that we reach more customers with information with the same employee resources and that we have generally created more efficient and targeted communication with customers,” says Lene Pedersen, adding: “And we hope to be able to see, when the solution has been implemented for a longer time, that the return temperature generally decreases.”
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For further information, contact: Elsebeth Arendt at elar@kredslob.dk