The Triodos Bank is one of few UK lenders to look kindly on loans for off-grid properties. Borrowing on unusual properties is made harder by big lenders like Nationwide and Halifax — they charge extra-high interest rates for the loans, while the Triodos offers a normal rate — for them the use of solar and wind energy is a plus.
While it is unlikely you will find cheap loans on Green properties, there are also a few local councils, for example Burnley’s Community Credit Union, offering averagely-priced loans for home improvements to save energy — but none are as wide-ranging as The Ecology which is “dedicated to improving the environment by promoting sustainable housing and sustainable communities.” The building society is focused on energy efficient housing; ecological renovation; derelict and dilapidated properties; small-scale and ecological enterprise and low-impact lifestyles (i.e.providing finance to those living off the grid).
The Ecology granted its first discount mortgage on an earth-sheltered dwelling in 1998. Earth sheltering combines low energy use and minimal disruption to land and flora. The mortgaged property forms part of the Hockerton Housing Project in Southwell, Nottinghamshire, one of the most advanced developments in sustainable housing in Europe.
The houses were designed by Brenda and Robert Vale, who designed Britain’s first autonomous house in nearby Southwell. That house was built by Hockerton founder member Nick Martin. The Martins and the four other families who have come together to create Hockerton Housing are effectively an ecological community, which is enshrined in their co-operative form of organisation.
The earth-sheltered aspect of the housing is the starting point and focus of an attempt by a group of people to live an holistic way of life in harmony with the environment, in which all ecological impacts have been considered and accounted for. Accordingly, and the Ecology Building Society is particularly proud of this — not only will the residents of the five houses be self-sufficient in energy and water, they will be aiming at producing all their own food and meeting as much of their needs for work from the site and project. This is no idle daydream – many of the elements to support these goals are now in place.
All residents own their properties but are also members of the Co-operative which manages and maintains the development. The houses are set in a 25 acre site, and residents have rights and obligations in respect of the land. This might take the form of work on the communal organic gardens, the aquaculture pond (which will provide fish), or maintenance of the reed bed system. There’s slightly less time for slumping in front of the telly here!
The development consists of five similar houses fronted by conservatories forming a terrace on a south facing slope overlooking a lake and wildlife pond. The view from the frontage overcomes the objection that earth sheltering must involve the loss of visual facility.
Simple materials and appropriate technology have been used to lessen the general environmental impact. Examples of this are the choice of bricks produced using waste methane gas, and the use of non-PVC cabling. In addition, the houses are not visible from the road, and over 3500 trees have been planted with more to come. Apart from contributing to the aim of increasing bio-diversity, this will counter any increase in CO2 emissions associated with the construction of the dwellings.
The houses feature very low energy requirements because there are effectively no space heating costs. The high thermal mass construction acts as a heat store, and there is sufficient heat gain from solar radiation, electrical appliances and body heat. The massive construction means that the internal temperature should remain at a comfortable 19-21 degrees all year round. Nick White of Hockerton says that so far this is being borne out in practice. In addition the buildings are heavily insulated. Hot water is provided from large water storage containers that can store 6 days supply of hot water, which will enable the group to make full use of a wind turbine once installed. This will be boosted by an energy efficient heat pump that takes up excess heat from the conservatory directly to the water tank. The turbine will also meet the ultra low energy requirements of the homes, which are less then 10% of conventional homes. Needless to say all lighting and appliances will be very low energy devices.
Rainwater harvesting and water recycling
Drinking water requirements will be met by collecting water from the conservatory roofs which is then filtered and mineralised. Water for other uses is collected elsewhere on the site and pumped to a small reservoir. Water efficient WC’s are being used which reduce water use by a third. Waste water passes through a septic tank and the resulting liquid effluent is cleaned in an ingenious low maintenance floating reed bed system and can then be safely used for irrigation purposes.
Innovation doesn’t cost the earth
Not least in terms of the many interesting features and advantages of the project is the low cost of construction – just 65,000 per house, discounting the costs associated with ancillary items such as the lake, reservoir and other amenities. This is partly due to the houses being terraced and through the sharing of services and facilities, but is also contributed to by the earth sheltering itself. A saving of about 10,000 per house was achieved through the self-build element of labour, but there is evidence that this type of construction has potential advantages in terms of affordability. Work on translating earth-sheltering techniques to affordable housing in an urban context is underway at the University of Glamorgan.
This is a project that the Society has been very pleased to be associated with. It demonstrates that truly sustainable housing is attainable and that the co-operative approach can be very effective in making the vision reality. Hockerton offer an information service, technical consultancy and site visits. To find out more phone Hockerton on 01636 816902 or email them at: firstname.lastname@example.org.
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