42watt secures OBI as a majority shareholder to scale up the energy transition in the building sector

MUNICH, January 27, 2026 – BONVENTURE portfolio company 42watt gains OBI as a strategic partner and new majority shareholder to further scale energy-efficient building renovation solutions. This step is an important milestone in 42watt’s development and underscores the growing relevance of digital solutions in the energy renovation market. For BONVENTURE, the transaction marks a successful exit from Fund BV4.

42watt is rethinking energy-efficient renovation: digital, data-driven, and scalable. To this end, 42watt has developed an innovative platform that enables homeowners to plan energy-efficient renovations in a simple, structured, and transparent manner. At the core is a data-driven analysis that translates complex building data into concrete, actionable measures. By intelligently combining software, personalized consulting, and implementation support, 42watt creates an end-to-end solution—from the initial analysis to completion.

“With OBI’s support, we can bring our technology to even more people. For us, this is the opportunity to apply the very lever for climate protection in the building sector that we’ve always had in mind: simple, digital, and accessible to everyone. We’re incredibly excited to move into the next phase of our mission with OBI,” says Marcus Dietmann, founder and CEO of 42watt.

In a short time, 42watt has established itself as an important player in the German market for energy-efficient building retrofits. The company benefits from strong structural growth drivers such as rising energy prices, increasing regulatory pressure, and a clearly growing demand for sustainable housing solutions.

A growing market with enormous potential

The building sector is one of the most significant factors influencing climate protection in Europe and is responsible for a significant portion of CO₂ emissions. At the same time, millions of residential buildings require energy-efficiency upgrades to meet climate targets and reduce energy costs in the long term.

Yet for many owners, the renovation process remains complex, fragmented, and difficult to navigate. This is exactly where 42watt comes in: With a digital, user-centered approach, the company makes energy-efficient renovation predictable, understandable, and scalable—thereby addressing one of the key bottlenecks of the energy transition in the building sector.

A Strong Partnership for the Upcoming Growth Phase

With OBI, 42watt gains a strategic partner with high brand recognition, a broad customer base, and a comprehensive omnichannel infrastructure. The majority stake lays the groundwork for even closer integration and enables a seamless customer journey—from digital planning and consultation through to implementation. 42watt is a compelling example of how digital innovation can make a measurable contribution to the decarbonization of the building sector. OBI’s entry as a majority shareholder is a powerful next step toward significantly scaling the company’s impact and making energy-efficient renovations accessible to broad segments of society.