Buildings or developments that are verified and certified as “net zero operational energy and/or carbon.” The building should demonstrate the highest levels of energy efficiency with the use of either renewables generated onsite or renewable energy procured offsite.
The brief for this project was to design a Passivhaus as a contemporary English cottage that would sit next to a number of traditional thatched houses in a rural English village. We wanted to create a new style of country cottage using the Passivhaus standards to drive a modern vernacular. Working closely with world leading sustainability/Passivhaus experts CoCreate Consulting we designed a family home that would have the smallest possible impact on its environment whilst developing a carefully crafted, modern rural vernacular.
Our client plays an active role with Extinction Rebellion and is a keen advocate for sustainable healthy living. Both of which had a key part in developing the project from the very start.
The proposal took on a simple rectangular footprint with pitched roof, echoing the local rural vernacular. Low eaves reduce the height of the building and tie-in with the adjacent thatched cottage. Our aim was to create a modern contemporary version of a rural cottage whilst reducing the external envelope to floor ratio, thus minimising the heat loss through the external building fabric. We designed the house to have an innovative split timber frame structure with Warmcel insulation minimising thermal bridging and increasing the use of recycled materials in the build. An exposed polished concrete ground floor slab provides thermal mass, flattening out temperature fluctuations. The design of the house took a fabric first approach. The U-values for the building fabric are below Passivhaus standards which means no primary heat demand is required for space heating. A high-performance whole house mechanical ventilation heat recovery (MVHR) system provides pre-heated fresh air whilst extracting warm stale air. An air source heat pump (ASHP) is used as the main primary heat source for hot water via a thermal store, with a secondary wood burning stove also connected to the thermal store. Wiring has been installed to allow the client to connect future PV’s to run the majority of the power in the house, including the ASHP. During winter the client can use timber from their coppice wood to heat all of the hot water for the house. Low energy LED’s are installed throughout the house, with smart controls to make sure energy demand is at a minimum. The client is in the process of connecting PV’s to help generate primary energy for electricity to reduce the power demand even further.
Our aim was to create a modern contemporary version of a rural cottage whilst reducing the external envelope to floor ratio, thus minimising the heat loss through the external building fabric. We wanted to create a new style of country cottage using the Passivhaus standards to drive a modern vernacular.
