Experimentation
When Eco Homes started the Old Apple Store project in early 2006 they were a company with just three years experience under their belts. This project was set to be their first venture into the world of sustainable living. Eco Homes now brand themselves as ‘specialist sustainable builders’ and ‘a national leader in sustainable building’. The company put a lot of time, effort and money into the project to make it work and consequently, they won two awards based on the sustainability of the project so one could argue that it was successful. The houses are metered and monitored via sensors to see how they perform throughout the year in terms of heat, electricity and water usage. This goes to show that it was all quite unknown and needed investigating(vi).
Before a team arrived to measure how airtight the properties were, it took three workers a total of three weeks to go around only two of the properties ensuring all the gaps were plugged. This would suggest that perhaps the build didn’t quite go as smoothly or accurately as planned despite the use of off-site prefabrication to lower the tolerances. However, on the other hand, without making mistakes along the way, how can the company learn and progress.
When it came to the technologies used, Eco Homes would have had to weigh up the potential risks against the rewards of using relatively new ideas and systems. Seven years ago photovoltaic cells would have cost significantly more than they do now, they were also a relatively mysterious installation for most home owners so there was no guarantee that people would want to buy into the scheme.
The finished houses were put up on the market at a price slightly higher than that of the local average, roughly £170 per square foot more. This higher price can be put down to three factors; this was a ‘prototype’ development, the first time that this sort of technology had been used in a family home. Specialist work to ensure the project could meet the CSH requirements for a level 5 build such as the installation of PV cells and heating systems(vii). Finally, this was the first time Eco-Homes were the primary contractor on a build and as such, weren’t as economically efficient as more experienced contractors would have been.
A lot of sustainably managed timber was used in the build in place if steel. All the external walls were pumped full of recycled newspaper (warmcel) and sheep’s wool was used as insulation on the flooring slabs. This coupled with the external facade of wood-fibre boards with a mineral render and triple glazing made any heat loss almost impossible. The walls have a U-value of only 0.14, to put this in perspective, new builds today aim for 0.25 and an average house in the UK will have walls rated at 2.1(viii). As for the windows, average double glazing has a value of 2.8, the triple glazing is approximately 2.5x less thermally conductive(ix). Six years later and this level of heat retention is still impressive.
Other, more commercially available ideas were also used such a photovoltaics to provide the energy required for lighting, wooden pellet burners which are more efficient and environmentally friendly than gas boilers and water saving features such as rain-water harvesting and ‘reduced-flush’ toilets and sinks.
This project, using off site pre fabrication and modular design could now be easily replicated again for another project elsewhere. It has been tried and tested and it works.