CeNZ-HighDB were recently part of a collaborative project that saw TV presenter Guy Martin conduct an ‘Ice Box Challenge’ as part of a range of building physics experiments for his recent House Without Bills programme for Channel 4. The challenge looked at how well Passivhaus buildings perform in the summer months.
The Ice Box experiment involved two sheds, one constructed to the exacting Passivhaus standard and one corresponding to the current building regulation standard. Guy Martin had borrowed the sheds from NMITE (The New Model Institute for Technology and Engineering) in Hereford and relocated them to his Lincolnshire home. The sheds were each filled with 0.5 tons of ice and left for a week during Augiust 2025. Guy opened up the boxes after a week to see how much ice remained in each. The Passivhaus specification shed was found to have lost 30% of its ice, with an inside temperature of 5 degrees C, while the building regulation shed had lost 60% of its ice and had an internal temperature of 11 degrees C.
The ice boxes used in the experiment form part of NMITE’s applied teaching and industry engagement activity. They are used to support learning on building performance, construction quality and low-carbon design, helping students and industry professionals connect design intent with real-world outcomes.
The ice box experiment was made possible thanks to a collaboration between the Passivhaus Trust, The New Model Institute for Technology and Engineering, and Edinburgh Napier University with support from Scotland Beyond Net Zero, and Housing Construction and Infrastructure Skills Gateway — The Edinburgh and South East Scotland City Region Deal, as well as CeNZ-HighDB. The Ice-Boxes were originally constructed by Built Environment – Smarter Transformation (BE-ST). Help with preparation of the ice boxes was also gratefully received from Passivhaus Trust member Herefordshire-based Mike Whitfield Construction.
The video of the experiment is now available to view on Channel 4’s YouTube channel, or below.