The instant eco-home

31/07/2009

In early July’s sweltering heat, it may be easy to forget the prohibitive energy costs that many social housing tenants face in winter. And for those rural tenants off the gas network who are dependent on more expensive electric or oil heating options, toasting those toes on shivery days can drag many into fuel poverty.

To combat this, Wherry Housing Association, together with Broadland Council and Sustainable Ecological Architecture Limited - or Search - has just begun a £100,000 research pilot in the Norfolk village of Ringland.

The Greening the Box project aims to prove that retrofitting existing homes is more cost-effective than building green homes from scratch. The ‘box’ is a 1920s, rural three-bedroom house off the gas network, with poorly insulated solid walls typical of much of Wherry’s stock. Its eco-refurbishment began in February, and the house is now fitted with energy-saving features which will be monitored over the next three years.

‘We’re hoping to prove that there’s less energy used and a reduction in carbon emissions in refurbishing an existing unit as opposed to building a brand spanking new home,’ says Mark Jones, managing director at Wherry Housing Association. He adds that the project team will also carry out an embodied energy analysis, which measures the total cost of the retrofit - materials, labour and technology. To keep these costs low they are using a local contractor and sourcing as many materials as possible from nearby King’s Lynn.

The human experience of living here will also be monitored. A family of four moved from their terraced house next door into the box in late June. Their energy usage will be compared with the family’s old home when a new family moves in next door.

Innovative materials

Dr Jeremy Harrall of Search, who conceived the project, believes its approach is unusual in not using standard retrofit technologies such as ground source heat pumps or air to air heat source pumps.

Instead, to save money and keep maintenance costs down in the future, the project uses ‘low’ technology, such as passive ventilation - there are no fans, boilers, radiators or tanks. It optimises natural sources of energy, for example, by enlarging the south-facing windows to get more warmth and light from the sun. Instead of radiators the house uses natural stack ventilation whereby pressure causes hot air to be drawn through the building, beginning with underfloor heating which is gradually emitted through a large concrete slab.

Dr Harrall says the box project will help ‘counter the menace of fuel poverty which threatens the lives of so many with limited means’.

‘At the same time,’ he adds, ‘the initiative will increase awareness of low-carbon economics and foster a degree of pride in householders and businesses alike in environmentally responsible housing and commercial accommodation.’

What has the project achieved so far? It’s early days, but already the house has been brought up to level 4 of the code for sustainable homes. ‘We’ve reduced the rate of heat loss tenfold,’ says Mr Jones. And its heating load - the amount needed to heat the home - has been reduced by more than half. Mr Jones says that the average terraced home emits five tonnes of carbon emissions a year, but this house is predicted to emit just one tonne.

The idea is to measure each aspect of the refurbishment work and, if it is as successful as has been predicted, apply it to similar housing stock in future.

‘I think the way to do this is to work in partnership with housing providers and local authorities,’ says Mr Jones, who has a financial model in mind.
‘If you retrofit a set of homes you’ll have savings for residents. If you can bring the long-term savings forward you can pay for the initial retrofit capital costs. So local authorities could bill users for that work and use the savings potentially to pay for that work.’

He says Wherry is currently in talks with Broadland Council about how the local authority can use potential savings to pay upfront for work. In turn, Broadland is speaking to the Communities and Local Government department about how the concept can be used further.

Progress will be measured every six months and updates will be posted up on the project’s website: www.greeningthebox.co.uk