Passive House design withstood meltdown conditions in a recent standard-to-standard duel with the Scottish building code. Glasgow, the host city for the upcoming 2021 UN Climate Change Conference (COP26), also offered up the venue to test and compare the thermal performance of two identically sized structures, filled with 917 kilograms of ice and left outdoors for two weeks.

The two competitors in the Ice Box Challenge were built in accordance with the Scottish building standard and the Passive House design standard respectively. Neither incorporated active cooling. However, results demonstrated the effectiveness of Passive House guidelines for window glazing, insulation levels, airtightness and reduction of thermal bridging.

All the ice in the Scottish standard prototype melted by the 11th day of the challenge, whereas the Passive House structure still retained 121 kilograms at day 14. That’s despite a coincidental heatwave during the challenge period.

Energy management specialists stress that the structure’s cooling features, embodying four of the five key Passive House principles, are equally effective in helping to retain warmth when it’s cold outside. Wintertime also sees the fifth Passive House principle — heat recovery ventilation — pressed into service.

“Housing associations in Glasgow are looking at this very closely and what it means to new build programs,” reports Michelle Mundie, who is part of the Glasgow’s municipal housing investment group.

“The Ice Box Challenge is a fantastic and fun way to illustrate the system in action,” concurs Ruairi Kelly, a Glasgow city councillor.