This Edwardian terrace in Muswell Hill, north London, has been extended and refurbished by its architect owner Ben Ridley of Architecture for London to create a comfortable, low energy home.

The project was built on a relatively constrained budget of £250K (a significant sum but represents good value for a whole house refurbishment built to a high standard in London) and aims to be an exemplar for the sustainable refurbishment of typical terraced housing in London. Both embodied energy and energy in-use have been considered in depth.

Design features include triple glazing, a continuous airtight layer and insulation to the entire building envelope. To preserve the architectural quality of the building, the front elevation is insulated internally while the side and rear elevations are thermally upgraded with external wall insulation. Wood fibre insulation was chosen for its combination of thermal performance and environmental credentials.

Masonry nib walls were retained at ground floor to avoid energy-intensive steel box frames. Natural materials including stone, timber and lime plaster were used throughout rather than cement-based products.

The rear extension is built in highly insulated 172 millimetre SIPS panels and all existing building elements have been upgraded to achieve a Passivhaus standard U-value of 0.15, or better.

A MVHR system provides pre-heated fresh air, creating a warm and comfortable home. The system also filters the incoming air, removing pollen, diesel particulates and nitrogen oxides (NOx) to create a healthy indoor environment.

Natural materials are used throughout the interior. In the kitchen extension, cupboards are veneered in oak, while the floor, worktops, and window seat are formed in grey limestone. In the living room, the old plasterboard ceiling has been removed to reveal the original timber beams. External walls throughout the home, are finished with lime plaster to create an airtight layer and a warm interior ambience. Upstairs in the master bedroom, the floor and many of the furnishings are finished in Douglas fir. Fluted limestone and an oak vanity unit feature in the main bathroom.

The rear garden has been richly planted right up to the facade of the extension with low lying native ferns and taller tree ferns (Dicksonia antarctica) for visual impact.

Low energy house has been shortlisted in the Don't Move Improve awards 2023.