Heat pump noise, placement and council rules in NZ

Where the outdoor unit goes affects how well your heat pump works, how long it lasts and whether your neighbours complain about it. Most New Zealand installs are straightforward, but there are rules to know about, especially close to a boundary, in an apartment or in a heritage area. This guide explains them in plain terms. Rules vary between councils, so treat this as a starting point and check with your council for your property.

Do I need a building consent to install a heat pump?

Usually not. A standard split-system heat pump in a house is generally not treated as work needing a building consent. The wiring must be done by a registered electrical worker, who certifies it with a Certificate of Compliance. Exempt work must still comply with the Building Code, and it does not override district plan rules or the need for a resource consent.

Heat pump hot water systems are different. MBIE's guidance says installing a new heat pump water heater is building work that generally needs a consent, with some exceptions when a certifying plumber replaces an existing water heater. If your quote includes one, ask the installer who is handling the consent. For ducted systems that need structural changes, such as cutting framing, confirm the consent position with your council before work starts.

What council noise rules apply to a heat pump?

Noise from your outdoor unit must stay within the limits in your council's district plan, usually measured at or inside the boundary of the neighbouring property. Limits are typically stricter at night than during the day. The exact decibel levels, times and measuring points vary between councils and zones, so check your own district plan or ask the council.

Councils can also act on excessive noise under the Resource Management Act. In practice most complaints come from a unit mounted right on the boundary, bolted to a fence or a shared wall, or running all night beneath a neighbour's bedroom. A good installer will think about this before drilling. Consumer NZ lists ignoring noise as one of the common heat pump buying mistakes, both inside and out.

Where is the best place to put the outdoor unit?

On a firm wall bracket or ground pad, close to the indoor unit, with free airflow and the clearances set out in the manufacturer's installation manual. Consumer NZ suggests the warmest side of the house, often the north side, can help in winter. It should also be away from bedroom windows, sheltered from strong wind and easy to reach for servicing.

• Clearances: follow the manual for gaps behind, beside and above the unit. Crowding it recirculates cold air and cuts efficiency.
• Neighbours: avoid the boundary fence line and walls facing a neighbour's bedroom. Wall brackets can pass vibration into the house, so ask about rubber mounts.
• Wind: strong gusts blowing straight at the fan can reduce performance. A sheltered wall or a baffle can help in exposed spots such as Wellington hillsides.
• Frost and snow: in cold areas, raise the unit off the ground so snow and defrost ice don't block it, and make sure defrost water drains away from paths.
• Coastal and geothermal areas: salt air and geothermal gases corrode coils. Consumer NZ warns that corrosion may not be covered by warranty, so ask about coated coils and warranty terms.
• Pipe length: a back-to-back install (outdoor unit directly behind the indoor unit) is usually cheapest. Longer pipe runs add cost, commonly quoted at around $50–$80 per metre.

Where should the indoor unit go?

High on a wall with clear air across the room, ideally blowing along the longest dimension of the space and not straight at where people sit. It needs a route for the refrigerant pipes, the power cable and the condensate drain. In a bedroom, check the indoor unit's quiet-mode noise rating on the specification sheet before you decide.

Can I install a heat pump in an apartment or unit title property?

Often yes, but you will usually need body corporate approval first. Exterior walls, cladding, roofs and many balconies are common property, and drilling through them or mounting an outdoor unit there requires permission under the body corporate's rules. Some buildings restrict external units or penetrations altogether. Get approval in writing before you book an installer.

If approval is refused, ask for written confirmation. Landlords can use this when dealing with the Healthy Homes Standards, which allow for situations where common property cannot be altered. Unit Titles Services explains how body corporate rules are made and changed.

What about heritage and character areas?

Some district plans restrict visible changes to the street-facing side of heritage-listed buildings or homes in special character areas. An outdoor unit on a side or rear wall is usually the simplest option, but check your council's district plan maps before assuming. For older villas, a ducted system can avoid a wall unit in the main rooms. See ducted vs high-wall for villas.