The Ice Box Challenge was a visual representation of the effectiveness of passive house design elements, presented as a collaborative effort from iPHA, Glasgow City Council, Passive House Institute, Edinburgh Napier University, Passivhaus Trust and Construction Scotland Innovation Centre.

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A city street with two small wood frame houses set up.

The display consisted of two small houses, placed side-by-side in Glasgow, Scotland’s city square. One house was built by standard Scottish building code, while the other implemented four of five passive house design elements. Each structure was filled with the same amount of ice, which was measured at the end of an established period.

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A small house with a green design being lowered via crane.

The results were undeniable, with the ice melting completely in the standard house within 11 days. Viewers could see the ice void days before the final measurements. In contrast, the passive house still had two large blocks of ice. In the end, the passive house still had 121kg of the original 917 kg of ice placed two weeks prior, even with unseasonably warm weather. 

A small house with a red design being lowered via crane.

This demonstration highlights the effectiveness of energy-saving passive design elements since no active cooling systems were allowed. Passive design incorporates five standard elements to significantly reduce the need for mechanical heating and cooling. This not only reduces the use of limited environmental resources but saves money for the homeowner too. 

Various stages of construction, with an image of two people in front of a wood frame at the top.

For this challenge, the homes looked nearly identical from the outside, but the passive house relied on window glazing, insulation levels, airtightness and reduced thermal bridges for keeping out the summer heat and maintaining a cool and comfortable interior. Due to the nature of the competition, the passive house didn’t include the fifth element of passive design — a ventilation system with heat recovery — which adds to the energy efficiency of the construction. 

A pile of ice blocks.

The passive home standard is becoming increasingly more common in projects developed by the Glasgow City Council and local housing associations. Michelle Mundie from the Housing Investment Group at Glasgow City Council says, “Housing associations in Glasgow are looking at this very closely and what it means to new build programmes. For tenants it means more comfortable homes with lower running costs.”

+ Ice Box Challenge

Images via © Passivhaus Trust, Kirsten Priebe