What Auckland does to a heat pump between services
Sheltered spots collect the most salt
BRANZ tested a building within 500 m of an Auckland harbour and found sheltered positions, which rain rarely washes, gathered about 3 to 8 times more salt than exposed ones. An outdoor unit tucked under eaves, a deck or a carport is exactly that kind of spot, so it misses the free rinse.
The harbours count as coast
BRANZ's summary of NZS 3604 puts land within 500 m of the coast, harbours included, and within 100 m of tidal estuaries and sheltered inlets in exposure zone D. On a city wrapped around harbours, that's a lot of back yards.
Humid air keeps the drain working
NIWA puts mean 9 am relative humidity at Auckland Airport at 82%, high in every season. On cooling, the indoor unit turns that moisture into water, so the drain tray and hose see steady use. Mitsubishi Electric NZ says servicing clears salt, dust and contaminants from coils and drain trays.
Few months off
Heat pumps were a main heater in 66.29% of Auckland Region homes in 2023, and NIWA says cooling demand peaks in summer. Henderson River Park logs 205 cooling degree-days a year on top of 1,250 heating ones, so filters fill with dust in both seasons.
How often should you book one here?
The warranty comes first. Rinnai NZ wants maintenance every year from installation by a Rinnai authorised service centre, and Gree NZ's card voids the warranty if maintenance goes more than 12 months. Mitsubishi Electric NZ calls yearly the minimum for standard home systems and says coastal ones may need more. BRANZ's lighter suggestion, a service check every 2 to 3 years, fits a lightly used unit well away from the water. Our heat pump servicing page sets out what each brand asks.
Corrosion is where the fine print gets strict. Rinnai NZ makes the owner responsible for extra corrosion protection in sea air, and Samsung's NZ warranty excludes salt spray damage. Black Diamond Technologies, which issues Mitsubishi Electric's NZ warranty, only covers corrosion where it applied its own Nyalic protection. Whatever protection you have needs keeping up.
What makes an Auckland service bigger or smaller
One high-wall unit with its outdoor unit at ground level is the simple end. A multi-room system means several indoor units to clean, and a ducted one adds a return air filter and time in the roof space.
Access counts too. Apartments, units and townhouses made up 27.9% of Auckland homes in 2023, and an outdoor unit on a balcony, roof or high bracket takes longer to reach safely. MHIAA, the distributor for Mitsubishi Heavy Industries, says its units must be reachable with a 1.7 metre ladder, with any extra access up to the owner.
Corrosion found on the day adds work: Temperzone's yearly list for Hitachi systems includes touching up damaged paintwork so rust doesn't take hold.
Questions to ask when you book
- Will you wash the outdoor coil, or only clean the filters?
- Will you check for corrosion and touch up any damaged paintwork?
- Does my brand's warranty accept your servicing?
- What will the service report list, and will it be dated?
- If the refrigerant reads low, will you find the leak rather than add more?
Your part between visits
You can
- Clean the filters as your manual says.
- Clear leaves and rubbish from around the outdoor unit after a windy spell.
- Note any smell, drip or new noise, and keep every service record.
Leave to a licensed installer
- Washing the indoor and outdoor coils.
- Clearing the drain tray and hose.
- Corrosion treatment, electrical checks and any refrigerant work.
What we'd do
Our take for Auckland
If the outdoor unit is within 500 m of the water, or tucked somewhere the rain can't reach, we'd book a service every year whatever the warranty says, and ask for the coil to be washed and checked for corrosion each time. Inland, with a unit that only heats a few evenings a week, we'd follow the brand while the warranty runs and then ease towards BRANZ's 2 to 3 years. Either way, we'd use someone who services heat pumps near the coast all the time, because they'll know where to look.