A pair of Victorian semis have been renovated to the Enerphit Plus standard by Guy Taylor Associates and Ecospheric


Kit Knowles, founder of eco consultant Ecospheric bought two adjoining semi-detached houses, then divided into flats and dilapidated, in Chorlton, Manchester. His ambition was to create an exemplary pilot project using old building stock. The resulting family homes meet the Enerphit Plus standard, awarded to buildings that as well as meeting the Enerphit standard – the Passivhaus benchmark for retrofit projects –also generate at least 60kWh/m2 in renewable energy each year.


Knowles’ approach was to retain as much of the building fabric as possible, rather than demolish and send it to landfill. To exploit the high thermal mass of the brick, most internal walls were finished with a parge coat of lime which allows them to breathe.


The project has exceeded the Passivhaus Institute’s requirements by specifying petrochemical-free, natural, breathable materials that avoid harmful off-gassing to maintain excellent air quality. Lime-based finishes include a graphene-enhanced lime paint that should eliminate cracking. Lime can also sequester VOCs and carbon, buffer moisture and, because of its alkalinity, prevent the build-up of mould.


Insulation systems used externally on the side walls and internally behind the front facade both comprise Steico timber I-joists, blown cellulose insulation, made from recycled newspapers, and wood-fibre board. The internal system includes a 38mm-wide ventilated cavity between the old brickwork and the new insulated structure.

An aerated concrete block bench system, specified for new foundations to the sagging bay windows, reduced the amount of concrete used. Copper guttering, downpipes and copings are expected to last 120 years.

On the west-facing rear facade, designed by Guy Taylor Associates, first floor windows are angled south towards the sun to maximise solar gain. Slimline glazing units are set in Organowood cladding, which is ‘pre-fossilised’ using inert silica to resist rot and UV degradation.

Hidden in the roof build-up, a Siga Majrex intelligent building membrane provides an airtight barrier whilst adopting biomimicry; using cactus-inspired technology to keep the building fabric dry.

Chimney shafts have been repurposed to accommodate services, including the MVHR system, heating and electrics.

A 60-square-metre array of PV panels on the roof powers the homes’ lighting and appliances and the Mixergy hot water tank. The thermocline-controlled system ‘floats’ the hot water on top of the cold to reduce heat loss, unlike a conventional hot water tank where incoming mains water cools any existing heated water.

The renovated facade includes what Knowles believes are the first stained-glass external windows used in a Passivhaus project. They were developed by Ecospheric Doors & Windows and Viking after surveying existing stained glass patterns in the surrounding streets.

Additional Images


Guy Taylor Associates, Ecospheric
Civil and structural engineer
Studio One Consulting
Passive House certifier
MEAD Energy & Architectural Design
Developer, contractor, M&E, passive house consultant
Wall, roof and floor insulation
Thermal breaks
Viking windows and doors
Ecospheric Windows & Doors
Roof windows

Organowood cladding
Hot water system
Novus 300 MVHR system
Panasonic PV panels
Environmental Building Services
Water-saving toilets
Water-saving fittings
Heritage lime plaster
Mike Wye & Associates