The Focus House in Finsbury Park will cover just 110m 2and will sit on the end of an existing row of Victorian terrace houses.
Insulated and protected from summer heat by zinc cladding, the low-energy scheme also features solar water heating and rainwater harvesting.
Explaining the project, practice founder Justin Bere said: 'The main objective was to exchange a large high-maintenance house for a compact low-maintenance, energy-preserving house that would allow a young couple and their children to shift the focus of their lives by transposing the traditional space division of the Victorian house to suit present-day need.'
He added: 'Healthy air and water quality is ensured by the rigorous selection of non-toxic materials, low-energy heat-recovery ventilation and whole-house water filtration and softening for drinking, bathing and showering.'
The development is the second in a series of eco-homes being built by the practice. The first, also in north London, is to become Justin Bere's own home.