04 Aug 2009
Greenhouse effects: Solar heating
Living a greener life — and creating a greener home — is a challenge we are all facing. For the past quarter of a century, I have been fighting for a more sustainable, eco-friendly world and was involved in the campaign that led to the Climate Change Act 2008. I was delighted to see the law turn into practical action last week, with measures to boost green energy, including policies on solar heating and future incentives for homeowners.
A lot is said about green electricity, but what is less often appreciated is that nearly 40% of greenhouse-gas emissions are due to heating.
Making our houses into power stations marks a big shift and will reduce our reliance on inefficient coal and gas stations. As the market grows, costs will fall.
One cost-effective small-scale renewable energy technologies is solar hot-water heating. Some systems use evacuated solar tubes that gather heat even on cool, cloudy days.
Our friends Liz and Steve recently installed a dual solar system. It provides hot water and energy for the central heating. The system was fitted on a south-facing roof at the same time as an extension was being built onto their interwar semi, so disruption was minimal.
At £7,000, it certainly wasn’t cheap, but they assure me that they would do it again.
There are two heat-gathering panels, filled with an antifreeze-type liquid pressurised to 3-4 bar; these are heated by the sun. The liquid transfers energy via a heat exchanger to water in a thermal store tank. This has been slotted into a former airing cupboard. The tank is linked to the gas boiler, which is set not to fire up while the solar system’s temperature remains above a certain level.
Their system — from — produced heat in the depths of winter and, since the summer (despite the cloudy skies), the gas boiler has not been needed for two showers, a bathtub, a washing machine, a dishwasher and general use. Their gas bills have plummeted.
Next time Russia threatens to turn off Europe’s gas, Liz and Steve will have secure heat and not be too worried about rocketing bills.
- Tony Juniper is a former director of Friends of the Earth;
You can find this at The Times Online: