Passivhaus Affiliate

Icebox Challenge Glasgow drives home the effectiveness of efficiency-first!

The impacts of the climate crisis have become clear to all of us in recent years. Heatwaves, floods, and wildfires have caused havoc across the world. Global warming is accelerated by human behaviour – unequivocally reinforced by the stark Intergovernmental Panel on Climate Change (IPCC) report published today. Buildings account for 35% of global energy consumption, most of this stemming from heating and cooling demand. 

 Icebox Challenge Glasgow closing ceremony. Icebox Challenge Glasgow: Red Scottish Building Standard box © Passivhaus Trust - Kirsten Priebe

The Icebox Challenge Glasgow engaged the public and raised awareness of the importance of energy efficiency and the energy-saving potential of Passivhaus buildings, calling into question whether our existing building standards are fit for purpose in a Climate Emergency. A fun challenge highlighting increasingly urgent issues brought into sharp focus today.

One box was built to the Scottish building standard, while the other met the international Passivhaus Standard. Both boxes were on display to the public for a fortnight, each holding an equal amount of ice. The remaining ice in each box was weighed at the closing ceremony on Friday 06 August. The results are staggering.


Ice Results

Starting with 1m3 of ice (917 kg) in each box, and after two weeks in St Enoch Square, the results of the Icebox Challenge Glasgow are in!

Green Passivhaus box

Red Scottish Building Standard box

Icebox Challenge Glasgow: Green Passivhaus box © Passivhaus Trust - Kirsten Priebe Icebox Challenge Glasgow: Red Scottish Building Standard box © Passivhaus Trust - Kirsten Priebe

121 kg ice retained

 (Despite the unseasonal Glaswegian heatwave for most of the fortnight!)

0 kg ice retained

 All the ice had melted by Monday 02 August - 5 days before the competition ended!

PHT research & policy director, Sarah Lewis: Thumbs up at the Passivhaus box and thumbs down at the Scottish Building Standard box. 

Through the photos above, we can literally see the difference better building design makes. It is inspiring to see how much of a difference can be made simply be adopting a fabric first approach. During the hot wather, the ice in the red box did not last for the full competition, and had completely melted five days prior to the closing ceremony.

The conditions inside the Passivhaus box were more stable and less susceptible to exterior conditions, protecting the ice from melting during this challenge despite a heatwave. The ability to regulate internal conditions regardless of what is happening outside is critical with rising global warming – Keeping warm in winter, but increasingly, cool in summer. Summer comfort is an important issue. The excellent fabric performance of Passivhaus buildings coupled with strategic, passive cooling techniques such as night ventilation and shading keep buildings comfortably cool. 

Reducing the energy that a building requires results in fewer carbon emissions and lower fuel bills, which also reduces fuel poverty. There are multiple co-benefits of building energy-efficient high-performance buildings, including improved occupant health & wellbeing, particularly of concern to the elderly & venerable.


Icebox Challenge Glasgow. © Matt Bridgestock

Icebox Challenge Glasgow in St Enoch Square © Matt Bridgestock

Both beautifully clad boxes have similar external appearances. The Passivhaus Standard does not require a radical change to the aesthetics of buildings, just a much more rigorous approach to the whole design and construction process, with careful attention to detail and certification through an exacting quality assurance process.

As we seek to translate climate pledges and net-zero promises into practical action - Passivhaus offers a robust & cost-effective solution that can be implemented now; an international standard proven to slash energy demand in buildings without compromising comfort, health, and wellbeing. The icebox challenge is a simple experiment that drives home the effectiveness of a fabric-first, efficiency-first approach. Watch the closing ceremony here via Instagram live.

Congratulations to Andrew W, who won a weekend stay at a Passivhaus B&B by placing a near-perfect ice bet.


Next-generation designers

As well as increasing public understanding of energy-saving buildings, this public installaion sought to engage upcoming architects & engineers who will design our future built environments.


The boxes for this challenge were designed, fabricated and installed by students as part of a Scottish design competition run earlier this year. Engaging students in these conversations is critical to the future of our industry. Young built-environment professionals need to feel inspired and empowered to design in a way that can be part of the solution to positive climate action. It's about fabric quality and design & as highlighted by our student team, project cross-discipline collaboration!

Sarah Lewis, Passivhaus Trust


Icebox Challenge Glasgow construction © Kyle Henderson Icebox Challenge Glasgow transportation © Kyle Henderson

Construction & transportation of iceboxes © Kyle Henderson, winning student design team member


As architects, it is our responsibility to design buildings that respond well to an ever-looming climate crisis. We must ensure our design decisions have a good impact on aesthetics & the construction process. Designing at scale requires a lot of critical thinking, problem-solving, sequencing, and project management. We are better designers after this process, especially with sustainable construction. We experienced all stages of the RIBA plan of works within a few months, which has been a great learning experience. We are thankful for the opportunity to show value for high-quality design and its impact on our comfort & the planet.

Lina Khairy, winning student design team member.


What next for the Icebox Challenge?

The Icebox Challenge will now travel to Strathaven for Green Building Week in Mid-September, before returning to Glasgow in time for display during COP26. Watch this space!

Icebox Challenge Glasgow: Michelle Mundie, Glasgow City Council 

With the sobering IPCC report stating this is a code red for humanity, this must be the decade of change! The challenge may be huge, but far from feeling paralysed by the scale of the task ahead, we should feel empowered through all the tools that provide a positive way forward. The Passivhaus Standard gives us ours for the building sector. 


All images, unless otherwise stated, © Passivhaus Trust - Kirsten Priebe


Further Information

Icebox Challenge Glasgow

Previous PHT story: 1 week countdown – 30 July 2021

Previous PHT story: Icebox Challenge Glasgow – 16 July 2021

Previous PHT story: Icebox Challenge Glasgow Winners - 17 June 2021

What is Passivhaus

IPCC Sixth Assessment Report - 09 August 2021

9th August 2021

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