Report: Water overlooked in domestic carbon-saving push

Hot water could soon become the largest source of domestic carbon emissions unless efforts are increased to curb water use and enhance energy efficiency.

That is the warning from a new report released today by the Energy Saving Trust and the Environment Agency, which argues that the government's initiative to improve building energy efficiency is guilty of failing to address the issue of energy being wasted to heat water.

The report found that while domestic water efficiency has improved, the increased use of power showers means that we are still using 150 litres of water per person per day – the same amount we used 10 years ago.

Ian Barker, head of water at the Environment Agency, said that the use of hot water had a significant carbon footprint. "Currently, six per cent of the UK's annual carbon emissions is related to water use – nearly 90 per cent of that is from hot water use in the home," he said. "It's clear we need to find ways of being smarter with the way we use hot water."

The study also found that while heating water already accounts for about 23 per cent of the energy used by a typical home, that proportion could rise to more than 70 per cent as measures to improve the efficiency of electrical appliances and space heating are rolled out.

"We undertook this research to pinpoint the exact areas in the home where water use is consuming most energy," explained Magda Styles, water and waste strategy manager at the Energy Saving Trust. "The results show that if we are serious about reducing energy in the home, we must include reducing energy used from hot water."

The report recommends that the government updates building regulations to ensure that rules governing hot water system design are as demanding as the energy-efficiency rules that now cover building insulation and design.

It also urges developers to include water-efficiency measures whenever they undertake energy-efficient retrofit programmes, and advises end users to undertake simple steps to save hot water and improve efficiency, such as lagging pipes and turning off taps when they are not being used. It calculates that these simple measures, combined with the use of more efficient appliances, could cut the carbon footprint of hot water by 30 per cent, saving the average home £225 in water and energy bills.

Styles said that EST was now planning to undertake a pilot study with advisory group Waterwise to look at how advice on water and energy efficiency could be better integrated.

The study comes on the same day as a report from the Environment, Farming and Rural Affairs Select Committee called on the government to ensure households and businesses had better incentives to reduce water use.