Lark Rise passivhaus

Typology: 
Residential
Status: 
In progress

Bere:architects were approached in the summer of 2010 to design a 2 bedroom passivhaus home on a sloping site in the Chilterns. The scheme has planning permission and the designs are currently undergoing considerable refinement.

The existing 1940’s building is constructed of uninsulated brick walls with single glazing to the majority of the windows. Warming the house to a comfortable temperature requires a continuous flow of heat, as any internal gains are quickly lost through the building fabric and the gaps around windows and doors. The resulting fuel bills are quite considerable even at current levels, however with rising energy prices they could soon become unmanageable.

It is the belief of the design team, that owing to the form and composition of the existing building it would not be practical or cost effective to address all of these energy issues with a retrofit solution. Redesigning the building from scratch however, allows such measures to be considered from an early stage and become an integral part of the design.

The proposed solution, which cuts the building into the slope, serves not only to reduce the built up appearance of the building, but also to insulate it from extreme fluctuations in temperature. Added to this is a thick layer of insulation wrapping the external surfaces and triple glazed windows to further reduce heat loss.

The building is to be constructed from precision engineered timber panels wrapped around an insitu concrete structure. 

In order to ensure the building will perform as efficiently as possible, the design is being tailored to meet the Passivhaus standard – a certification route which ensures well designed, highly insulated, draught proof buildings, typically using around 85% less energy than a standard house.

Initial energy studies which have been carried out using PHPP modelling, show that despite the north-westerly aspect of the site it should be possible to meet the stringent heating requirment of 15kWh per square metre. To give this some context a typical Victorian house uses in the region of 400kWh per square metre.

The resulting building will be warm, comfortable and require little or no heating in order to maintain a stable internal temperature. This will reduce running costs for the occupants and minimise the dependance on resources. The site also presents the opportunity to show how it is possible to create energy efficient buildings, which nevertheless respect local planning polices, on non-optimal sites.