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38. Replacement or repositioning of water heater connected to controlled heat source

Water heater mounted to an external wall

A building consent is usually not required to replace or reposition a water heater connected to a controlled heat source, if it is carried out by an authorised person.

What the law says

Schedule 1 of the Building Act 2004 states the following:

The replacement of any water heater (including the repositioning of an existing water heater) if the replacement water heater is connected to, or incorporates, a controlled heat source or, if connected to or incorporating more than 1 heat source, 2 or more heat sources all of which are controlled.

Guidance on the exemption

This exemption enables an authorised person (refer to the glossary) to replace and/or reposition an existing water heater (of any type), as long as all the heat sources of the replaced or repositioned water heater are controlled. This exemption will not apply if a water heater has a heat source that is not controlled (eg a wetback connected to a solid-fuel heating appliance, or a solar thermosiphon system).

A controlled heat source has controls or devices that ensure the water temperature in the storage tank is no greater than 90°C.

Check with your council

If the proposed scope of the building work is outside the scope of this or any other exemption (eg adding solar collectors to an existing water storage heater, which has provision for solar connection and is not being replaced or repositioned), we suggest that you consider applying to the council for an exemption 2.

The council can then decide whether or not it will require a building consent. Before doing this, we recommend that you talk to the council to gauge whether or not it is prepared to exercise its discretion under exemption 2 on your project.

Any repair or maintenance of part of a water heater (which may include the replacement of a component of the water heating system) falls outside the scope of this exemption. Exemption 36 deals with repairs or maintenance of part of a water heater.

Replacing a hot water cylinder which is connected to an existing wetback falls outside this exemption (refer to exemption 37 for open-vented systems).

Examples where this exemption could apply

Water storage heaters

  • Replacing an existing valve-vented water storage heater with a thermostatically controlled valve-vented water storage heater (eg electric to electric, gas to gas, electric to gas, or gas to electric). 
  • Repositioning an existing valve-vented water storage heater that has a controlled heat source. 
  • Replacing an existing open-vented water storage heater with a valve-vented water storage heater that has a controlled heat source. 
  • Repositioning an open-vented water storage heater, when in the new position it is connected to a controlled heat source.
Solar water storage heaters

  • Replacing and/or repositioning an existing water storage heating system comprising a water storage heater that includes controlled solar collectors. 
  • Replacing or repositioning an existing electric or gas water storage heater with a water storage heater system that includes controlled solar collectors.
Heat pump water storage heaters

  • Replacing a water storage heater with a heat pump water storage heater. 
  • Replacing and repositioning an internal water storage heater with an external heat pump water storage heater. 
  • Replacing an external water storage heater with an external heat pump water storage heater
Instantaneous water heaters

  • Replacing or repositioning an instantaneous water heater that is thermostatically controlled. 
  • Replacing an existing storage water heater with a gas instantaneous water heater.

Examples where building consent is required

Adding a solar collector to an existing water storage heater (even if the existing water storage heater has provision for solar connection). A building consent is required because this exemption only covers replacement or repositioning of existing water heaters.
Adding a wetback (not a replacement wetback) connected to a water storage heater. A building consent is required because this exemption only covers replacement or repositioning of existing water heaters. Also the wetback is an uncontrolled heat source.
Adding a split heat pump (not a replacement split heat pump) to an existing water storage heater. A building consent is required because this exemption only covers replacement or repositioning of existing water heaters.

 

 

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: