Learn how Wattsense drives smart energy efficiency and scales effortlessly with MongoDB Atlas

THE CHALLENGE

Turning complex building data into actionable insights

Improving the energy efficiency of buildings is increasingly a priority of organizations everywhere. Across the European Union, for example, a staggering 75% of buildings are not energy efficient, representing a significant untapped opportunity for climate action.

However, for building owners and facility managers, the challenge lies not just in upgrading infrastructure, but in doing so cost-effectively and with minimal disruption.

Wattsense, a Siemens company, is helping to close this gap by enabling smarter, faster, and more flexible building connectivity in existing commercial and social housing properties across France, the UK and elsewhere in Europe.

Wattsense provides a plug-and-play solution that is easy to install, cost-efficient and can be connected in half a day. It allows users to remotely monitor and control buildings’ equipment such as HVAC (heating, ventilation and air-conditioning) systems, regardless of whether a traditional Building Management System (BMS) is in place or not. Its hardware device, the box, is designed to integrate with both legacy infrastructure and modern wireless protocols like LoRaWAN, which facilitates energy-efficient, long-range communication between sensors and control systems. This allows even very dated buildings to be retrofitted quickly and affordably without needing to replace existing equipment. “We want to have an impact on the environment,” says Mohamed Zenadi, Engineering Fellow at Wattsense. “To do that, we have to think a little bit in the past; we don’t push people to replace their existing infrastructure—we augment it, we make it possible to talk to others.”

Crucially, Wattsense's architecture can be connected through 4G, and is compatible with both proprietary and open protocols. At the heart of its offering is the ability to interpret and translate raw data from diverse sources into actionable insights. To make this possible, the company has built an extensive framework of encoders and decoders that process incoming data from more than 1500 pre-defined compatible sources, including 800 LoRaWAN sensors and other systems. This data not only needs to be captured reliably, but stored securely, searched efficiently, and scaled seamlessly to support Wattsense’s growing deployments across Europe. To meet these demands, Wattsense identified MongoDB as its database solution, leveraging its flexibility, scalability, and performance to power real-time, data-driven decision-making.

OUR SOLUTION

Selecting a flexible, low-overhead solution for ultimate reliability

To power its connected building platform, Wattsense sought a database solution that could easily handle complexity, scale effortlessly, and support rapid iteration. Working with a lean development setup at the time, simplicity and reliability were paramount. An early experiment using Azure Cosmos DB with MongoDB-compatible drivers was short-lived. “To be honest, I wasn’t happy with it,” said Zenadi. “I like software you can set up and forget about. Having something that works well, is efficient, and that you don’t have to spend time with was important for me.”

This thinking led Wattsense to MongoDB Atlas in 2018—a fully managed cloud database that met the company’s need for speed, scalability, and minimal overhead.

MongoDB Atlas stood out not only for its ease of setup but also for its ability to align with Wattsense’s development strategy. The company needed to move fast, iterate quickly, and handle flexible, evolving schemas. MongoDB’s document model enabled exactly that—allowing engineers to store large, deeply nested documents containing complete device configurations; ‘think twins,’ as Zenadi puts it. “It allows us to reduce the number of drawings we have to make and the maintenance we have to do,” he adds. “MongoDB Atlas makes it easy for us to use.”

Equally critical was MongoDB’s powerful aggregation framework, which Wattsense uses extensively to efficiently extract and work with data from nested arrays, enabling advanced functionality by targeting specific items directly within those arrays.

A major turning point came in 2021 with the introduction of native time series collections. Previously, Wattsense maintained a separate SQL database to manage time series data, creating additional overhead. With time series now integrated directly into MongoDB, the team was able to consolidate its architecture—simplifying operations and improving performance. Today, MongoDB manages around 600 gigabytes of physical data and 1TB of logical data, covering everything from device metadata to streaming sensor inputs, all within a unified system.

“Now we rely almost 100% on MongoDB for almost everything,” says Zenadi. “For configuration, it's MongoDB; for managing metadata, it’s MongoDB; and for time series it’s MongoDB. We’re very happy with it.”

OUTCOME

Powering seamless operations with zero downtime and cost control

Since adopting MongoDB Atlas, Wattsense has experienced tangible benefits that have significantly improved its business operations and scalability. A standout advantage is the platform’s exceptional reliability: since 2018, Wattsense has experienced zero downtime with MongoDB Atlas. “That’s been amazing,” says Zenadi. Indeed, it contrasts sharply with Wattsense’s previous time series database, which experienced frequent outages during upgrades, creating operational challenges. MongoDB Atlas’s fully managed service, including seamless upgrades and replication, removes this burden entirely, allowing Wattsense to focus on innovation without worrying about database maintenance.

Scalability is another critical benefit. MongoDB Atlas automatically adjusts capacity based on demand, scaling up during peak usage and scaling down during quieter periods. This dynamic scaling improves performance while controlling costs, offering a serverless-like experience without the associated high expense. This robust performance supports Wattsense’s growing data ingestion needs without impact or bottlenecks, aligning neatly with the company’s expectations. “We knew from the beginning that MongoDB Atlas is well suited for ingesting a lot of data in parallel,” says Zenadi. “We’ve never had an issue with it, even though overall it’s almost 4x the amount.”

Additionally, Wattsense found migration from a manually created cluster to an infrastructure-as-code approach using Terraform entirely straightforward, enabling DevOps teams to manage the database infrastructure safely and efficiently within existing workflows.

Overall, MongoDB Atlas has empowered Wattsense with a highly reliable, scalable, and easy-to-manage database solution. This foundation supports the company’s data-intensive operations and positions it for continued growth without the operational headaches of managing multiple systems or worrying about downtime and performance issues.

Looking ahead, Wattsense plans to expand its use of MongoDB Atlas by integrating Atlas Search to power faster, more efficient queries across its entire equipment database. By leveraging Atlas’s built-in Lucene-based search capabilities, the team aims to unify and streamline search functionality across platforms, further improving performance and user experience.