- Ice Box Challenge

Sweden Takes on the ICE BOX Challenge: Building for a Sustainable Future

The ICE BOX Challenge is a global initiative that has been organized in over 17 cities worldwide for the past 18 years. It aims to raise awareness of sustainable construction and energy efficiency. Now, IG Passivhus Sverige has brought this challenge to Sweden, where the concept of the Passive House started in the 1980s.

“For the first time ever, students from five different Swedish universities will participate in the international competition, the ICE BOX Challenge, where they will compete to build the most sustainable and energy-efficient mini-house.”
– IG Passivhus Sverige

The competition, which integrates five of the UN’s Sustainable Development Goals, involves storing two one-ton blocks of ice in a purpose-built mini-house for a month. One of the houses is built according to national energy standards, while the other is a sustainable, energy-efficient, and circular house with the lowest possible climate impact. At the end of the competition, which will culminate in a ceremony on 6 June 2025, the mini-houses will be opened to measure how much ice has melted in each. The results will clearly illustrate how different building standards impact energy consumption and sustainability.

“I am very proud to be leading this Swedish ICE BOX Challenge this year and am very curious to see the 10 different boxes in five climates across Sweden on National Day, 6 June 2025.”
– Simone Kreutzer Wesslund, CEO IG Passivhus Sverige

Pushing the Boundaries of Sustainable Design

Students of architecture and engineering are tasked with designing and constructing two ice boxes according to the competition’s guidelines. One box will adhere to Sweden’s BBR29 building code, while the other will feature a Passive House building envelope (PHPP), with full insulation, no thermal bridges, airtight construction, Passive House windows, and more. The design should also allow for easy assembly and disassembly, with a focus on materials that minimize climate impact (considering circularity, recyclability, climate declarations, and buildability). In spring 2025, the two ice boxes will be placed in a public location (TBA) for one month to test their performance.

MEET THE STUDENT TEAMS

MEET THE MENTORS

What is the Ice Box Challenge?

The Ice Box Challenge is a public installation that visually demonstrates the benefits of energy-efficient buildings.

Two boxes are constructed—one to local building standards and the other to the international Passive House Standard. Both are filled with either 1m³ (917kg) or 1 metric tonne (1000kg) of ice and placed in a central, high-traffic area. After a set period, the remaining ice in each box is measured to show how well each one insulated against heat.

This challenge makes the often invisible concept of energy efficiency tangible and engaging. Passive House buildings, with their significantly lower energy demands, play a crucial role in climate protection.

WHAT IS A PASSIVE HOUSE?