The Government’s controversial Green Deal, which allows homeowners to borrow to improve home energy efficiency, has focused on expensive options such as double-glazing or solar panels. But what about easier, cheaper choices? One that receives little publicity but can bring dramatic savings, is cutting limescale in water systems.
Plumbers and engineers have long known about the damage and costs caused by limescale – calcium carbonate deposits that form when water is heated – but water suppliers, housebuilders and homeowners are only now waking up to the savings.
Of the average home’s total annual energy consumption – 23,000 KWh and costing £1,250 – the Government estimates that 84 per cent goes on heating. Much of this involves heating water to use directly and to fill central heating systems.
Limescale on boiler elements and in pipes drastically reduces the efficiency of a heating system or even wrecks pumps and other equipment.
The Carbon Trust, which advises on energy efficiency, calculates that every millimetre of limescale on a boiler’s element boosts energy consumption by seven per cent. Limescale builds in hard water conditions at about 1mm a year.
Research by the University of Plymouth found that a boiler with no limescale took 90 minutes a day to supply the average home’s hot water, while a boiler with 5mm of scale took more than four hours. With 10mm of scale, this rose to more than six hours, adding hundreds of pounds to a household’s annual gas bill.
In 2006, the Government required new homes in hard water regions to have water softeners installed. Several local authorities are now putting them in during council property refits.