What Are the Essential Requirements for Building Consent on Heat Pump Water Heaters?
Building Performance (building.govt.nz) recently updated details about heat pump water heaters. Here’s a summary of the key points.
What Are Heat Pump Water Heaters?
Heat pump water heaters are energy-efficient systems that transfer heat from the environment into water using a compressor and refrigeration circuit. For every kilowatt (kW) of electricity used, they typically transfer three kW of heat.
There are two main types:
Integral systems: Heat pump and storage cylinder are combined.
Split systems: Heat pump and storage cylinder are separate, connected via pipes.
Diagram 1 shows how a heat pump water heater works. Typically, three kilowatts (kW) of heat from the outside is transferred to the water for every one kW of electricity supplied to the compressor.
Do You Need a Building Consent?
The need for building consent depends on the installation scenario:
Building Consent Required
Consent is necessary for new or additional installations, including:
Installing a heat pump water heater in a new home.
Adding a system alongside an existing hot water setup.
Adding a heat pump water heater for a new ensuite.
Building Consent Not Required
If installed or supervised by a registered certifying plumber, building consent is not required for:
Adding a split heat pump water heater to an existing storage water heater.
Replacing an existing storage water heater with a heat pump water heater in the same location.
Replacement Guidelines
Exemptions from building consent apply to like-for-like replacements, such as:
Replacing open-vented with open-vented systems.
Switching from open-vented to valve-vented systems (without supplementary heat exchangers or solid fuel heaters).
However, mixing incompatible systems or connecting supplementary heating components may require consent.
Compliance with the Building Code
All heat pump water heater installations, whether requiring consent or not, must meet the Building Code standards. Key clauses include:
B1 Structure: Ensure seismic restraints to handle earthquake forces.
B2 Durability:
Heat pump water heaters: minimum five-year durability.
Storage water heaters: minimum 15-year durability, with normal maintenance.
E2 External Moisture: Seal any penetrations in the building envelope to maintain weathertightness.
G9 Electricity: Electrical installation must be certified safe by an electrician.
G12 Water Supplies: Ensure safe water supply, storage, and delivery.
H1 Energy Efficiency: Systems must be energy efficient for hot water delivery.
For the full content about Building Consent on Heat Pump Water Heater, please click here.