Yesterday evening, I find myself outside the magnolia-columned Royal Society buildings in Carlton House Terrace for a talk on a hot topic of the moment – housing for a low carbon energy future.
A girl comes round the queue with leaflets and stickers labelling us ‘WLTH’ – I feel like I’m on a dating website. We process in through red-carpeted halls past a sweeping stairway to the lecture hall, where an infrared camera is set up for the best demonstration of the greenhouse effect I’ve ever seen.
Illustrations by Julien Ferrato
It’s nothing too dramatic to look at, the demonstration with which Professor Tadj Oreszczyn opens the lecture. Just a man sat next to a jug of hot water, filmed by this infrared camera and projected on to the screen behind. Then he puts a plastic bin bag over himself (don’t try this at home, kids..) which was opaque to visible light, but lets all the heat radiation right through – we still see him clearly on the camera. It does get better, though. A bag full of air in front of the camera diffuses the heat a little. A bag full of carbon dioxide, filled from a fire extinguisher, absorbs and reflects back a lot. Simple as it is, this is the first time I’ve *seen* carbon dioxide being a greenhouse gas. You should be able to find it streamable here
Professor Oreszczyn is head of the Energy Institute at University College London, and after the demonstration, he got on to the focus of his talk : the ‘Great British Refurb’. If we are going to hit the UK targets for carbon reduction, making our buildings much more energy efficient is going to be huge. The government projections reckon that, by 2050, half of our carbon reduction will come from carbon capture, renewables and nuclear energy, and the other half from reduction in demand and increase in efficiency at the point of use.
Getting a clear idea of what energy is used in a house is really quite difficult, though. Electricity, gas, wood, coal and sunlight all come in – and we use them in all sorts of ways. We spent an average 3% of household expenditure on energy bills in 2000-2006, which is half of 1980 spending. In real terms, energy is cheap. If you wanted a human/bicycle-powered house, though, you’d need 8 athletes pumping away 24/7 – at minimum wage, that’s £400 000 a year.
The Warm Front Scheme has been set up to improve the health and comfort of low-income homes by improving energy efficiency. They received £350 million in 2007/8, refurbishing about 170 000 homes. They monitored 3000 of them, and the inside temperature went up, mould went down, energy bills went down, people felt more comfortable and this presumably helped mental health and avoided winter deaths (there are still, shockingly, about 20 000 excess winter deaths in the UK).
‘In theory, theory and practice are the same, but in practice, they’re not.’
The physics is always right, says Professor Oreszczyn, we just apply it wrong. The Warm Front houses used a third more energy after being redone – very strangely. Partly, people took the improvements as more warmth and comfort, rather than less energy, which was at least partly the point of this project. Also, draughtproofers went all round the houses blocking up cracks, then central heating was put in, putting a lot of new holes throughout, undoing some of the other work. And in terraced houses, the party walls were never thought of as places where heat could be lost – but for years now they’ve been built with a cavity for soundproofing, which heat just shoots straight up through to the roof.
There are some good projects in the real world now, like this old victorian house which was refurbished in Camden to reduce its carbon use by 90% and is being continuously monitored.
There’s a lot of information out there, if you want to find out more. The Lancet recently ran a series on Energy and Health, and the Sustainable Energy Academy or the Energy Saving Trust are both good places to start.
Tags:
efficiency, energy, heating, royal society
