When winter hits Scandinavia and temperatures fall with the snow, having plenty of hot water is a real treat. It’s also a big expense — typically an apartment building’s No. 3 energy expense after heating and cooling. While no one wants to pay more than necessary for any utility, few apartment tenants (or their landlords) have a way to monitor their individual resource consumption.

In Sweden, a world leader in renewable energy and sustainability, a new Internet of Things (IoT) solution is seizing the opportunity to make apartments more efficient, conserve natural resources and save money. Stockrose, a Swedish property management company, is out to change the way building owners and tenants consume resources — so there’s incentive to take a shorter shower over a luxurious bath.

In fact, Stockrose has evolved from the old model of dividing utility costs equally between tenants to a model where those who consume less, pay less. Stockrose worked with Eniga, a provider of intelligent cloud solutions, to connect the approximately 250 buildings and 10,000 apartment units it operates to Microsoft Azure IoT technology. They began by tracking hot water usage, which accounts for about 20 percent of the energy bill in single-family homes — and much more in apartment buildings.

The result of their collaboration is a building-as-a-service offering that will save Stockrose property owners an estimated $42 million in hot water costs within 10 years.

“Sustainability is not just a buzzword,” says Richard Lind, CEO of Stockrose. “Sure, it’s a big promise, but it’s also a win-win for a number of stakeholders. It’s certainly a win for property owners who can lower their operational costs.”

Stockrose chose Azure as the only IoT platform that offers the security features, performance and scalability it needs to support such a complex solution. The hybrid on-premises and cloud infrastructure connects at least five sensors in each apartment unit to the cloud. It starts with on-premises gateways running the Azure IoT Gateway SDK. The gateways enable Eniga to work with the diverse sensors from multiple vendors speaking different protocols that already exist in Stockrose’s buildings. Another benefit of the SDK is that its gateways can preprocess the data to minimize the amount of data sent to the cloud, which reduces the cost for Stockrose.

Other Azure services then process and analyze sensor data to provide building owners with insights into resource usage. Azure IoT Hub ingests data from the millions of sensors in buildings connected through the gateways. This gives Stockrose the flexibility to bring smart buildings online quickly and affordably without ripping and replacing existing infrastructure.

“There are a lot of investments that have already been made, particularly in electricity and smart metering,” says Lind. “So what you need is a platform that is more or less agnostic about sensors and network topology. And that’s one of the good things about the Azure platform.”

Beyond water heaters, the IoT platform can easily connect to all of a building’s systems, from HVAC to solar panels. It can also be used to detect water leaks and measure the snowpack on roofs to help avoid costly damage and insurance claims. Another benefit is that it opens opportunities for Stockrose to offer new products to property owners, such as water-saving shower fixtures and appliances.

Stockrose can also offer predictive building maintenance as a service that can cut costs and increase efficiency. “I know that Azure IoT Hub can scale, and that we can take advantage of additional capabilities like real-time analytics,” says Lind. “We can also use machine learning, which will be a real cornerstone of our service for customers that want predictive maintenance.”

Read the complete story of how Stockrose is putting IoT to work in its buildings. Learn more about how Microsoft IoT can transform your business today.