Friday January 30, 2004
Big money could be disappearing down your shower drain
Many New Zealand households could be washing big money down their shower drains because of the growing use of mains
pressure hot-water systems, a new study shows.
The Building Research Association of New Zealand (BRANZ) has today released the latest findings from its Household
Energy End-Use Project (HEEP).
Now in its seventh year, the internationally-recognised study monitors all energy use (electricity, natural gas, LPG,
solid fuel, solar water heating), as well as room temperatures, in New Zealand households from Kaikohe to Invercargill.
Final data collection from 400 houses will be complete in early 2005.
BRANZ principal scientist and HEEP project leader, Nigel Isaacs, says the steady growth of mains pressure hot-water
systems has resulted in higher water flows in many New Zealand homes.
Measurements taken from more than 350 household showers showed mains pressure systems have flows that are almost 50
percent higher than the older, low-pressure systems (10.6 litres per minute, compared with 7.2 litres per minute).
‘The result is not just higher energy bills, but also higher water bills in areas where households must pay for their
water,’ Nigel Isaacs says.
‘One way of combating the problem is to install low-flow shower heads. They can produce big savings.’
The HEEP research shows that changing from a standard head to a low-flow head on just one shower in Auckland could save
$90 a year ($180 for two, and so on). About half the savings are from energy, and the other half from reduced water
supply and removal costs. Over all of Auckland the savings would amount to more than $21 million dollars per year, as
well as water savings of 3.5 million m³ per year (about 3 percent of Auckland’s current annual water use)
Fitting low-flow shower heads would also reduce demand on local water systems. That would be valuable for places such as
the Kapiti Coast which has water supply issues throughout summer.
Further material, including the HEEP report Executive Summary is available on BRANZ website
www.branz.co.nz/main.php?page=HEEP
ENDS