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80% House

prewett bizley

80% House by Prewett Bizley Architects is a deep low-energy residential retrofit and extension project of 2010 in the United Kingdom, London. While the property functioned as a neglected, poorly insulated Victorian terrace house before the intervention, the transformation of 2010 provided a multi-level rear extension, a high-efficiency rooftop bedroom-cum-study, and an integrated MVHR ventilation system, increasing the usable surface area from a fragmented historical layout to an optimized, low-emission urban home.

This project contributes to the social-ecological transformation by engineering an 80% reduction in carbon dioxide emissions within a traditional Victorian building envelope, demonstrating an early benchmark for deep urban retrofits. It combines a rigorous airtightness strategy and high-thickness insulation with a mechanical ventilation heat recovery system to stabilize internal temperatures year-round. Furthermore, the installation of a rooftop photovoltaic array provides over half of the home's annual electricity needs, proving that historical housing stock can be successfully transitioned away from fossil fuel reliance without demolition.

City

Hackney, London

Country

United Kingdom

Use Before

Housing

Use After

Housing

Year

2010