Company information
Hockerton Housing Project Trading Ltd. No. 3179843
The above Company is registered in England & Wales.
The energy hierarchy places different energy services in order of their cost-effectiveness at curbing carbon emissions, and is key to our decision-making at Hockerton Housing Project.
Energy efficiency, or ‘fabric first’ builds energy saving in, so energy savings are sustained over the life of a building or product for a relatively small upfront cost, More information available when we talk about
How was planning permission achieved?
In August 1996 the Project made UK post-war planning history by obtaining special permission to build a sustainable housing development on agricultural land.
Planning permission was achieved despite a number of hurdles, including a comprehensive legal document, a section 106 agreement (see next question), attached to planning consent.
Nick Martin (one of the project members), combined his interests in renewable energy and low impact developments to consider various concepts that lead him to the earth-sheltered option. In the meantime he won the tender in 1993 to build the home of Prof. Brenda and Dr. Robert Vale, the UK’s first sustainable town house. It is an autonomous house with ‘net zero CO2’ emissions, of low embodied energy, deriving power from photovoltaic arrays and passive solar heating.
Nick Martin was so convinced by many of the construction principles that he commissioned Dr. Robert Vale to design a rural hamlet of 5 earth sheltered sustainable dwellings at the Hockerton site, to similar energy and environmental performance standards – autonomous and with ‘net zero CO2’ emission.
Every effort has been made to use natural, traditional materials to their full potential. The use of standard off-the-shelf materials and products has been balanced with the benefits of ease of construction, cost effectiveness and reliable performance. The single storey, modular layout of the houses with repeating units allows for constant spans and economies of scale for fitments such as doors and windows.
• Minimization of environmental and health hazards by use of non-toxic products and materials.
• It reduces the visual impact of a development making the homes almost invisible from roads or points of public access
• Provide a temperature buffer for the homes due to its insulation properties and the fact that soil temperature lags air temperature by several months.
The houses are of a high thermal mass construction, which is able to store and release heat energy over a long period of time, thus maintaining a stable internal temperature somewhat akin to a storage heater. As air temperature drops heat is released. The materials that provide the bulk of the thermal mass are concrete blockwork, concrete beams and clay tiles.
Primarily, the foresight, willingness and flexibility of Co-operative Bank & Ecology Building Society to work together overcame the challenge of financing the project. The Co-operative Bank initially provided loans, which were later converted to mortgages with Ecology Building Society. These two organisations specifically support projects with environmental aspects.
An internal contract was agreed within the group committing each family to provide finance up to a common stage of development. Each family had to separately fund their share of the work. A finance sub-group calculated relative payments and a position of equity were achieved on a monthly basis
Glazing is an important feature of the houses both in terms of energy performance and aesthetics. At Hockerton, the homes are SW facing, which gives a slight emphasis to afternoon light. The elevational design, enhanced by the roof angling upwards makes good use of low winter sun penetrating to the back of the dwellings. This design, therefore, both provides good internal daylight and maximizes passive solar gain through the conservatories.
The homes have been designed to maximise light input when occupants most need it in the depths of winter; the pitch of the ceiling matches that of the shallow sun at its winter equinox. This allows sunlight to penetrate fully to the back walls. Conversely at the summer equinox there is minimal light penetration through the building self shading itself from the high sun. This however helps prevent over-heating of the building.
The conservatories are obviously well lit, whilst the very large windows and doors that open onto them provide good lighting to those rooms where it is desired, such as lounge, kitchen and bedrooms. The back of the houses where natural daylight is reduced, have been reserved for areas that such lighting is not an issue – such as bathroom, shower, and utility room.
The interior finishes were selected in keeping with the principles used for choosing building materials. This included choosing products from sustainable sources, of minimal embodied energy, recycled materials where possible and of low potential toxicity.
Wood products were sourced from sustainable timber sources. Paints were chosen that were low in ‘Volatile Organic Solvents (VOC’S)’. PVC wiring and pipework were substituted with alternatives. Clay tiles were used rather than carpets (tiles are more natural, have a lower embodied energy and last longer). Where possible formaldehyde compressed boards were avoided. Many items, such as kitchen units were made from recycled materials.
Initially all homes were fitted with ‘Air to Water’ heat pumps to provide hot water. This system utilizes excess heat created in the south facing conservatories. The hotter the air, the more efficient the system becomes – however they are capable of providing hot water energy efficiently at relatively low temperatures. There is a high capacity for storing such gains during hot periods or via excess wind energy, due to the very large hot water tanks, which have a capacity of 1,500 litres. Overall the combined system of heat pumps and super-insulated thermal water stores reduced the energy requirements for hot water by about 75%.