Why most heat pump installs skip the consent
The Building Act 2004 says building work needs a consent unless the law exempts it. Schedule 1 lists the exemptions, and one covers the hole every heat pump needs: a penetration of up to 300 millimetres for pipes, cables or ducts through an existing house, or a building of no more than 3 storeys, weatherproofing included.
Councils say the same in their own words. Christchurch City Council says installing a heat pump doesn't require building consent but must be done by registered electricians who certify their own work. Westland District Council lists installing an air-conditioning system in a home among work that may not need one. Your own council's building pages will say how it treats them.
When a consent is needed
It depends on the heating. Christchurch City Council says you need a consent to install or move a solid or liquid fuel heater, and Tenancy Services says the same of installing or modifying wood and pellet burners. Christchurch also wants one for heating that uses reticulated water, such as radiators or underfloor heating connected to the drinking water supply, and for all commercial heating and ventilation systems.
Permanently fixed gas heaters don't need a consent in Christchurch, but a certifying gasfitter has to install or supervise the work and certify it.
A heat pump water heater is a different product from one that heats a room, with its own consent questions. Don't carry the answer for one over to the other: ask your council about hot water.
Skipping a consent you needed has teeth. The Building Act allows a fine of up to $200,000, plus up to $10,000 for each day the offence continues. If the work's already done, the owner can apply to the council for a certificate of acceptance.
No consent still means rules
Exempt work must still meet the Building Code, mustn't leave the building less compliant than before, and mustn't breach any other law, such as the district plan. For a heat pump that usually comes down to three things: a weathertight wall penetration, an outdoor unit that stays within the noise limits, and permission where the building isn't only yours.
In a unit title, read the body corporate's operational rules before any work starts. Tenancy Services gives the example of a rule that bans external heating units on common property without the body corporate's consent. Ask before you book an install date, not after the bracket is on the wall.
If the home is a heritage home or heritage protection rules apply, Tenancy Services' advice is to contact the council about any restrictions first.
How loud can an outdoor unit be?
Noise limits for things like a heat pump's outdoor unit are set in each council's district plan, and they vary by zone and time of day. Auckland's are the only ones we've sourced, so treat them as an example, not your town's rule.
In Auckland's residential zones, the Unitary Plan caps noise from any activity, measured within the boundary of the neighbouring site, at 50 dB LAeq from 7am to 10pm Monday to Saturday and 9am to 6pm on Sunday. At all other times the limit drops to 40 dB LAeq and 75 dB LAFmax. Auckland measures under NZS 6801:2008 and NZS 6802:2008, and an activity that can't meet a permitted noise standard needs a resource consent.
The quieter night limit is the one that matters for heating, because a heat pump warming a bedroom on a frosty night runs during exactly those hours. Consumer NZ warns that the outdoor unit can be quite noisy and that you should think about the neighbours if it has to sit near your boundary.
Meeting the building rules doesn't settle the noise question. The district plan limits apply in their own right, so a unit can be legally installed and still be too loud.
Reading the noise figures on the label
The Zoned Energy Rating Label can show how loud a unit is at full power. The number inside the house icon is near the indoor unit and the one outside is near the outdoor unit; ducted units show only the outdoor figure. Showing noise is optional here, so some labels leave it off, and lower is quieter.
EECA gives some reference points: about 30 dBA in a quiet home, 50 dBA inside a quiet car, 60 dBA for a normal conversation and 75 dBA for a running vacuum cleaner. The label figure is measured close to the unit at full capacity on cooling, so it isn't the same thing as a district plan reading taken at the boundary. It's still the easiest way to compare two models before you buy.
Choosing an outdoor spot the neighbours can live with
Map the quiet rooms first
Yours and next door's. BRANZ says to locate outdoor units away from quiet areas such as bedrooms.
Leave it room to breathe
BRANZ asks for 500 mm of open space on the faces where air goes in and out, 100 mm on the others, and at least 100 mm under it. A cramped unit works harder.
Mount it solidly
BRANZ says units must be stable, and that in retrofits particular care is needed so sound and vibration insulation actually works.
Check the warranty's view
BDT, Mitsubishi Electric's NZ distributor, excludes issues from outdoor units installed close to neighbouring boundaries or other noise sensitive spots. Other brands have their own conditions.
Keep it maintained
BRANZ says regular maintenance stops worn bearings and other parts from becoming noisy. A unit that's grown louder with age may need a service, not a move.
Don't move an outdoor unit yourself
Shifting an outdoor unit means disconnecting refrigerant pipes and electrical wiring. Refrigerant work is for a heat pump technician, and the wiring is prescribed electrical work for a registered and licensed electrical worker. Never climb onto a roof to look at a roof-mounted unit. If a noise problem means it has to move, have the installer do it and give you a new Certificate of Compliance, and check the warranty first: Rinnai NZ, for one, excludes equipment re-installed somewhere other than its original location.
What you can sort, and what needs the installer
You can
- Read your council's building pages on heat pumps and heating.
- Get body corporate consent in writing, if you're in a unit title.
- Ask the council about heritage rules, if they might apply.
- Talk to the neighbours before the outdoor unit goes up.
- Compare the noise figures on the labels of the models you're considering.
Leave to a licensed installer
- The wall penetration and its weatherproofing.
- Mounting the outdoor unit and isolating its vibration.
- Moving a unit, including the refrigerant work.
- The electrical connection and the Certificate of Compliance.
- Any gas heater work, which needs a gasfitter.
What we'd do
Our take
For a standard heat pump in a house, we'd read the council's own page before even thinking about a consent application, because the job is often exempt. The effort belongs on the outdoor unit instead: away from bedrooms on both sides of the fence, on a solid mount, and with its label noise figure compared before you buy. In a unit title, we'd have the body corporate's consent in writing before the installer books a date.