Energy
Designing homes to conserve energy and use it efficiently, from sources that cause least environmental harm.
Water heating
According to the BRANZ Household Energy End-Use Project (HEEP), water heating accounts for 29% of energy use in an average New Zealand house.
Find out about:
- achieving energy-efficient water heating
- key decisions when specifying water heating systems
- energy sources
- storage cylinders
- continuous flow systems
- heat pump water heating
- solar water heating.
Achieving energy-efficient water heating
To achieve energy efficiency in water heating:
- install efficient hot water outlets that minimise the amount of hot water used
- use energy-efficient heating sources that do least harm to the environment
- plan to minimise heat losses from the system.
Minimise heat losses by:
- heating and storing only as much water as is needed to meet peak demand
- only heating water to the temperature needed to meet regulatory requirements
- installing a Grade A insulated cylinder (specifying an additional cylinder wrap will further reduce heat losses)
- locating the cylinder in a warm space
- ensuring all hot water pipes are insulated
- minimising the length of hot water pipes by locating the hot water cylinder central to water heating services
- incorporating appliances that heat their own water.
Key decisions when specifying water heating systems
Key decisions that have to be made as part of the design process include:
- locations of water heaters and outlets
- heating energy source
- whether to store hot water or use a continuous flow system
- the capacity of the system.
The choice between a storage or continuous flow system may be influenced by:
- the energy source readily available
- space available for installation
- use patterns and number of occupants within the house
- distance between the water heater and the point of use within the house.
More information
- www.smarterhomes.org.nz/energy/water-heating
- www.smarterhomes.org.nz/energy/solar-water-heating
- BRANZ Household Energy End-Use Project (HEEP)


