The now-dismantled dth-nul-energihus in suburban Copenhagen offers a vision of a future that never came to pass. Built during the oil shock of 1973 by the Technical University of Denmark, this squat, white building—consisting of two living spaces divided by a glass atrium and topped with a spine of solar panels—was one of the first attempts to create a zero-energy home.
The nul-energihus did not quite make it to “zero-energy” but its vital statistics were nevertheless impressive. It only needed 2,300 kilowatt-hours of energy a year, roughly the same as six modern fridges. Its copious insulation and solar-heating system kept it warm even in frigid Danish winters. When a family moved in, things deteriorated a bit, notes Marc Ó Riain, an architecture professor at Munster Technological University. Hair clogged up the filtration system, which recycled heat from wastewater, and occupants had an unfortunate habit of leaving windows open.
Yet these were problems that could have…
This article was written by and originally published on www.economist.com