Scheme Summary
The scheme consists of two 3 - 4 bed houses constructed on a brownfield site in a small village in Wiltshire. Westlea Housing Association was a founding partner of the 1NTEGER Intelligent and Green housing project that seeks to build homes with environmental and technological features. The scheme was developed in conjunction with Bree Day Architects.

Scheme Details

At the end of summer 1998, a decision was taken to pilot two houses built to 1NTEGER principles, in partnership with North Wiltshire District Council. The scheme was completed in August 1999. It achieved a SAP of 100, Housing Quality Indicator of 77%, Lifetime Homes Standard and Secured by Design.

The houses are designed to have very low running costs for heating, lighting, water and general maintenance. They are also constructed using environmental friendly techniques and materials. As the 1NTEGER project introduces 'intelligent' aspects the houses also include accessible cabling for telephones, modems, computers, CCTV security lighting controls from master switches and precise heating controls.

The houses integrate the Lifetime Homes standard and space flexibility to optimise the use of the houses as family needs change. Some walls are removeable which can provide for an extra bedroom or a home working area. Space standards exceed those in a conventional house, partly resulting from using the roof space (usually a redundant area) as living space.

Environmental Features
The properties use wood based products for most of the construction. All timber is sourced from sustainable managed forests.

The timber frame is panelled in timber, insulated with cellulose (recycled newspaper), 200mm in walls and 300mm in roofs, and clad in low maintenance Red Cedar.

Roof mounted solar water collectors will pre-heat water which, together with a thermal store, should meet half of a household's hot water needs. A single glazed two storey sun store is located at the front of the house. This acts as a heat buffer, pre-heating air before it enters the house.

Grey water recycling uses bath and sink water for flushing 6 litre WCs.

Low energy light fittings are installed throughout.

Timber frame low emissivity argon filled windows complement the high levels of insulation. Natural ventilation is provided to the airtight houses by the installation of a passive ventilation system.

Savings
The houses should produce a saving of 50% on heating, due to high levels of insulation; 50% on hot water, due to the use of solar panels; and 30% in water use, due to water efficient appliances and grey water recycling.

Costs
As only two units were built, there was no benefit from the economies of scale associated with larger development. The total build cost for 115 m² floor area for each house was £97,500, or £848/m² (1999 prices). This included the demolition of an existing concrete (PRC) house and making good to the adjoining private property. Demolition included asbestos removal, materials reclamation and crushing all concrete off site for hardcore. The houses cost 35% more to build than Westlea's standard homes. The pilot project was possible due to additional funding via the local authority. In addition to this, manufacturers and suppliers provided support through free or discounted products to demonstrate technical feasibility.

Developer's Comments
The houses have been occupied for over a year and monitoring has taken place. Residents are most pleased with the extra space arising from using the roof space, the easily accessible storage space and lower heating bills resulting from the effective insulation standards.

The second most significant benefit is the solar hot water system. This has reduced bills by up to 50%. Residents view the glazed solar spaces as positive. They add heat, provide a thermal buffer and give a sense of airiness to the homes. Monitoring shows this area has added a significant temperature benefit to the adjacent dining area, especially during the autumn months. As some over-heating has been experienced during the summer an automatic ventilation system will be installed for use in future summers. Residents are pleased with the grey water recycling system. By explaining to them how the system works before they moved in, issues relating to water colour and its treatment have not been a problem. The water and cost savings compensate for any difference arising from 'normal' expectations.

Monitoring has also shown that room temperatures stay relatively stable. The average temperature is 20°C, with the minimum temperature being 16°C.

Westlea is taking the lessons learned from the pilot project and applying some 1NTEGER features to a new development of 54 homes at Stokes Croft, Calne. This development was completed in March 2002.

Contact: Stephen Parker,
Westlea Housing Association,
Methuen Park,
Bath Road,
Chippenham,
Wiltshire.
Tel: 01249 466066
Fax: 01249 466007
Email: stephen.parker@westlea.org.uk