Showers using too much power

By REBECCA WALSH

That morning shower could be costing you a lot more than it needs to.

A just-released study has found that showers in many New Zealand households are using more water than necessary and bumping up power bills.

The report by the Building Research Association of New Zealand estimates that by switching from a high-flow to a low-flow shower head an Auckland household could save $90 a year for each occupant.

Across Auckland savings would amount to $21 million and water savings of 3.5 million cubic metres a year, according to the Household Energy End-Use Project (HEEP).

Principal scientist Nigel Isaacs said nearly three-quarters of the more than 300 houses in the survey were on low-pressure systems but the remainder, mainly newer houses, were on mains pressure. That meant greater water flow.

Figures showed a shower attached to a mains pressure system delivered on average 10.6 litres of water a minute compared to 7.2 litres of water for a low-pressure shower.

Mr Isaacs said the issue was going to grow as new homes and apartments had mains pressure systems installed. Older houses were also being retrofitted with mains pressure hot water systems.

"If you go from an old house to a new house, your power bill and water bill are going to increase without you understanding why," he said.

A mains pressure system involved water going from street pipes outside to the hot water cylinder and out the shower. Typically the water pressure was hard. Older houses tended to have low or medium-pressure systems.

Mr Isaacs said one way of reducing the problem was to install low-flow shower heads and that did not mean taking a piddly shower.

John Simmiss, chairman of the Master Plumbers Board, said most New Zealanders were determined to have a good shower "and if it uses a lot of water, so be it" but increasingly water-saving devices were being called for by councils, engineers and designers. A basic low-flow shower head cost $30 to $60.

At Waitakere City Council a project is under way to help New Lynn residents reduce their water usage through use of devices such as high-performance shower heads.

Gretchen Schubeck, executive director of the EcoMatters Environment Trust, which is running the trial of 2500 homes, said people were often stunned by how much water they used.

The council's goal was to reduce the average person's water use of 197 litres to 160 litres a day.

Some of the other key findings from the Branz report:

* More than 40 per cent of water cylinders delivered water at unsafe temperatures.

* One in three cylinders had inaccurate thermostat control.

* Even when users set the thermostat at a safe temperature, one in three cylinders delivered water at a temperature that was unsafe.