O.K. Energie Haus GmbH – Building with Responsibility, Roots and Impact O.K. Energie Haus GmbH is a trailblazer and thought leader in sustainable construction – in Burgenland and beyond. As a regional flagship company based in Großpetersdorf, we have been creating timber buildings for over two decades that are far more than just architecture: they are climate-positive living spaces. Our commitment: technically excellent, energy-efficient, and ecologically consistent construction – carried out with passion and precision. With around 50 in-house employees and a strong network of more than 200 skilled regional partners, we design and build single-family homes, medical practices, office buildings, schools, and commercial structures – all in timber frame construction, from concept to completion. We rely on local wood, cellulose insulation made from recycled paper, and short supply chains – ensuring top ecological standards, certified klimaaktiv and climate-fit. Our philosophy is simple: build with responsibility. With our own photovoltaic system and a growing fleet of electric vehicles, we not only produce emission-free – we shape future-ready building processes. Each cubic meter of wood in our projects stores one ton of CO₂ – with an average of 40 buildings per year, that’s around 9,000 tons annually. In total, our timber construction has already stored over 32,900 tons of CO₂ – a tangible contribution to climate protection. But our commitment doesn’t stop at the foundation. As part of our in-house climate initiative, we have planted 30,000 trees in the region together with partners, clients and supporters. This tree-planting campaign actively promotes biodiversity, improves local microclimates, and restores carbon sequestration to where it’s most powerful: in vibrant, climate-resilient forests. O.K. Energie Haus stands for sustainable thinking, tangible quality and a clear promise: We create spaces with heart, foresight and integrity – for people, the climate, and a future that lasts.