Gisborne summers, and the coast
Summer heat
Wikipedia's climate table, citing NIWA, gives Gisborne a January mean daily maximum of 25.8 degrees, warmer than Hamilton's February 25.1 or Tauranga's 24.4.
Cooling demand
NIWA gives Gisborne AWS 189 cooling degree-days a year. That's more than Tauranga Aero AWS's 176, but well short of the 1,483 heating degree-days Gisborne logs.
Winter nights
Gisborne Aero averages 39 ground frosts and about 6 air frosts a year, and NIWA says katabatic drainage, cold air sliding downhill, lowers the city's winter minimums. The July mean daily minimum is 5.5 degrees.
Sea spray
BRANZ says homes near breaking surf at beaches such as Waikanae and Midway fall in exposure zone E, severe marine, under E2/AS1, and anything within 500 m of Poverty Bay in zone D.
Damp homes
Tairāwhiti had the highest share of people in damp homes of any health district in 2023, at 35.8% (EHINZ). That matters for where a cooling unit's water ends up.
Sizing a heat pump for a Gisborne summer
EECA's rule depends on the main job. A unit bought mainly for cooling should be sized on its 35 degree cooling capacity, and one bought mainly for heating on its heating capacity at 7. In a sunny Gisborne lounge, check the cooling figure even if heating is the main use, because BRANZ says cooling capacity is generally about 10 to 20% below heating capacity.
For a unit that will do a lot of cooling, BRANZ suggests choosing one with a high energy efficiency ratio (EER). On the Zoned Energy Rating Label EECA regulates here, blue stars rate cooling efficiency. Read the ones for the Cold zone, which covers all of New Zealand.
Don't neglect winter. With cold air draining into the city on still nights, EECA's check still applies: the heating capacity at 2 degrees should match or beat the figure at 7.
Cooling in a damp house
Cooling wrings water out of the room air, and that water has to go somewhere. BRANZ says condensate hoses should run to drains or gardens, not onto paths, which matters even more in a house that's already damp.
Dry mode helps on a muggy day, but Consumer NZ says a purpose-built dehumidifier does that job better, and neither replaces proper ventilation. Our Gisborne heat pump page covers the damp side.
The outdoor unit near the beach, and at night
Near Poverty Bay and the surf, salt is the risk. BRANZ says coastal outdoor units need extra anti-corrosive coatings, and LG's warranty, for one, excludes deterioration of coils and external surfaces from corrosive air. Ask what protection the unit will have and whether it suits the brand's warranty terms.
Summer cooling also runs late, when the neighbours have their windows open. Noise limits sit in each council's district plan, and a council sign-off doesn't protect an outdoor unit from noise enforcement later. BRANZ suggests keeping the outdoor unit away from quiet areas like bedrooms, and that should include the house next door. Our consents and noise guide has more.
What to ask a Gisborne installer
- What's the cooling capacity at 35 degrees, and the heating capacity at 2?
- What's its blue star rating for cooling in the Cold zone?
- What corrosion protection will the outdoor unit have this close to the sea?
- Where will the condensate drain go?
- How far will the outdoor unit be from the nearest bedroom next door?
What we'd do
What we'd look for in Gisborne
We'd choose a heat pump that heats well at 2 degrees and check that its cooling figure covers the hottest room, rather than buying for summer alone. Near the beach, we'd want corrosion protection named on the quote. And we'd ask someone who installs heat pumps for both cooling and heating every week to look at where the afternoon sun hits before they size it.