• The Econergy heat-pump water heater has the potential to cut household hot-water bills by two-thirds nearly everywhere in the country. But our test results show that some other models won't give worthwhile savings in all our climate zones.
• Some manufacturers/distributors have work to do to ensure that their installed products reliably work as intended.
• Large-scale introduction of heat-pump water heaters has the potential to conserve the country's electricity resources and reduce greenhouse gas emissions.
• A study should be undertaken to identify a safe minimum hot-water storage temperature. The building code should then be amended if necessary to reflect the findings.

More information
 

• Energy Efficiency and Conservation Authority: www.energywise.govt.nz
• Hot Water Association: www.nzhwa.org.nz

More from consumer.org.nz

• Solar hot-water systems

Report by Bill Whitley.