Meet the Mentors

Mare Mitrevica, Engineer, Certified Passive House Designer, and Accredited Passive House Certifier, 

“Offers energy efficiency and building physics calculation services for IG Passivhus in Sweden and internationally. Services include thermal bridge analysis, energy balance and life cycle cost calculations, building life cycle assessments (LCA), Passive House certification documentation, and certification support. Her experience spans single-family homes, social housing, schools, kindergartens, and public gyms.

“My motivation for participating in the Ice Box Challenge is to raise awareness of energy-efficient and climate-conscious design among students entering the construction industry in the coming years.”


Michael Staffas, MSc, Certified Passive House Designer

Co-owner and founder of Build Well Scandinavia AB and a certified passive house designer since 2013. He led Sweden’s first certified passive house villas and has supported nearly all major passive house projects in Sweden since 2016, including schools, preschools, LSS, port halls, and ecological villas with high energy efficiency and low CO₂ emissions.

Build Well supplies and installs certified thermal envelope products like window systems, exterior door systems, and airtightness systems for optimal indoor comfort and sustainability.

“I hope my experience helps students in this unique project, spreading awareness about sustainable building.”


Birgitta Grebius, Arkitekt SAR/MSA, Certified Passive House Designer

Birgitta is the Co-founder, co-owner, and CEO of Bleck Arkitekter AB and has been a certified passive house designer since 2013. Birgitta was the lead architect for Sweden’s first passive house preschool. Bleck Arkitekter combines innovative design with practical, sustainable solutions, including renovations of culturally significant buildings.

Birgitta joins the Ice Box Challenge to promote the integration of energy efficiency and aesthetics, aiming to demonstrate that sustainable design can enhance both functionality and beauty.

“By showcasing successful examples, we can inspire others to adopt sustainable practices that conserve resources and enrich our environments.”


Zack Norwood, Passive House Expert, Project Manager

Dr. Zack Norwood specializes in solar energy and building energy efficiency. He led the first EnerPHit renovation in the USA and managed a Swedish renovation of a million-program apartment building, featuring an advanced BIPV facade (building integrated photovoltaics) and roof, one of the most energy-efficient in the Nordics. Currently, Zack is working on the world’s first passive house oyster farm in Rhode Island, USA.

“I’m excited to contribute to the Ice Box Challenge and engage with future designers and engineers. This competition has the potential to make a big impact by reaching a broad audience.”


Lukas Ljungqvist, M.Sc. Architecture, Passive House Expert

With over 15 years of experience in urban planning and architecture focused on energy efficiency (international passive house standards) and sustainability, Lukas is currently pursuing a PhD at KTH Royal Institute of Technology. He works as an urban strategist for the City Planning Administration of Stockholm, aiming to enhance sustainable urban development methods that integrate energy and climate goals.

As the city coordinator of the Senseable Stockholm Lab, Lukas collaborates with KTH and MIT (Massachusetts Institute of Technology) researchers to develop AI and big data tools for sustainable urban planning.


Viktoria Ljungberg Hötzel, Arkitekt SAR/MSA, Certified Passive House Designer, Partner at VIEW

With curiosity, attentive listening, and an environmental focus, she works as an architect. Since 2016, after gaining experience with the IG Passive House standard through her work on Glänningeskolan in Sweden, she has incorporated passive house principles into her designs.

Her projects span schools, kindergartens, apartments, and public gyms, in both new builds and renovations. A key question she asks every client is, “What climate goals do you want to achieve?” Her main aim is to meet and surpass these goals, creating buildings that bring joy and safety.

“As a mentor in the Ice Box Challenge, I hope to inspire others to explore new ideas while gaining insights I can use in my own work. The Ice Box results are not only exciting but also essential in tackling today’s environmental challenges.”


Barbro Titti Eriksson, Arkitekt SAR/MSA/KKH-R, Certified Passive House Designer

Part-owner and chairman of TOL Arkitekter, and a certified passive house designer since 2019, she aims to create sustainable architecture that enhances a place’s identity while balancing aesthetics and functionality.

She is the lead architect for multiple passive house projects in Sweden, including public preschools, school buildings, and holiday homes, and is involved in efforts to reduce CO2 emissions during construction and building operations. Trained in restoration, she also works with culturally and historically significant buildings.

“My motivation as a mentor in the Ice Box Challenge is to share my knowledge and experience with students on the importance of resource- and energy-efficient architecture.”


Ingo Theoboldt, Passive House Designer and Passive House certifier

His interest in renewable energy began in the early 1980s, expanding to green building in the 1990s during his studies in engineering physics with a focus on environmental engineering. Since 2007, he has worked on Passive House projects in the UK and Scandinavia, becoming a certified Passive House designer and consultant in 2009.

With expertise in sustainable energy systems, IT, quality management, and business administration, he has contributed to over 200 Passive House projects globally. His work includes supporting manufacturers in developing Passive House components and offering services like energy balance, thermal bridging analyses, and climate dataset creation.

“I’ve worked on Passive House schools, homes, offices, sports halls, and even a hospice. Through the Ice Box Challenge, I hope to share my knowledge in sustainable construction even further.”


Jesper Waage, Passive House Designer, Construction Engineer

Jesper Waage, a 43-year-old engineer with a background in building technology from Lund University of Technology, has over a decade of experience as CEO at Knut Jönson Ingenjörsbyrå. Participating in the Ice Box Challenge, he aims to highlight the importance of energy efficiency in construction and sees this as a chance to mentor students and raise awareness about the positive impact of passive house design on energy use.