Working collaboratively with the client, ARCO2 have produced one of the most sustainable new properties within the south-west. Constructed from around 85% local Douglas fir, oak and western red cedar and super-insulated with reclaimed lambs wool, the building sequesters huge amounts of carbon and therefore begins life with a high degree of carbon credit. The split-level design capitalises on the south-facing wooded sloping site providing passive solar heating through southern glazing and the inclusion of a substantial glazed solar core heat store extending over three storeys on the southeast corner of the building. This heat store is harnessed and vented into the building using a central ventilation system with heat recovery during the winter and provides a rapid ventilation stack during summer months. Coupled with 4.2kw of PV and solar thermal panels only minimal heating is required during the coldest winter days it is supplied with two small wood-burning stoves. The insulated floor slab over the 2 lower storeys also adds thermal mass to the scheme further moderating temperature extremes. The energy consumption is such that the residents are in credit with the utility company.