Saturday, October 31, 2009
From the Guardian.UK:
The UK government has a target for all new homes to be zero-carbon by 2016.
The term "eco home" is now so used and abused that it barely retains any trace of meaning. So when we learn that Channel 4's Grand Designs is to feature yet another eco home this week it's tempting to pre-emptively reach for the remote. (Incidentally, my favourite featured home was Ben Law's Woodsman Cottage in Sussex, but it was hardly a viable solution to all our housing needs.)
But I must admit that I am slightly intrigued by this week's offering simply because it claims to draw on centuries-old ideas, such as timbrel vaulting. It has often struck me when talking about how we might green up our housing stock just how often the solutions can be found by thumbing through the history books. Much of what is prescribed – insulation, insulation, and a bit more insulation – isn't exactly rocket science.
Our ancestors realised all this long ago, but as fuel becomes ever more available and affordable we largely lost the need to care about wasting energy in our homes. However, things are fast changing and we need to urgently rethink how we use and save energy at home. After all, households account for 27% of the UK's carbon emissions.
The programme this week will feature a home called Crossway located near Staplehurst in Kent. Its owner, architect Richard Hawkes, says it is one of the first "zero-carbon" (another overused term) homes in the UK. What sets it apart is its structural reliance on a large vaulted roof which spans 20m. Much of the house is covered in earth to aid insulation and help it to blend into its rural setting. The earliest known example of "Catalan vaulting" – the forebear of timbrel vaulting – is a building in Valencia dating back to 1382 and it is a very resource-efficient way of creating a strong, expansive roof.
"The vaulting gives the house plenty of structural strength but obviates the need for embodied-energy intensive materials such as reinforced concrete," says Dr Michael Ramage, who helped to design the home. He is an architectural designer based at the University of Cambridge's Department of Architecture with expertise in structural design and construction technology. "It also provides it with great thermal mass, enabling the building to retain heat, absorb fluctuations in temperature and reducing the need for central heating or cooling systems," adds Ramage.
The UK's first example of a combination photovoltaic and thermal heating system has been installed alongside an 11kW biomass boiler to provide the home's heating and power needs.
I fully support such innovation and am intrigued to see how it all works and performs, but I'm always distracted by one thought: what about our existing housing stock? Surely, the greater task ahead of us is not how we improve the energy efficiency of new housing – ever-tighter building regulations and planning laws should make that a given – but how we go about overhauling the 20-plus million homes already standing across the UK, most of which leak heat for fun.