Choosing, in order
Decide which rooms need heat
Just the living area, or bedrooms too? Consumer NZ says split systems work best in the main living area of an open-plan home. Closed-off rooms usually need their own unit, a multi-room system or ducting.
Pick a type that suits each room
The comparison below covers the main ones. BRANZ says indoor unit types aren't interchangeable, so a unit designed to sit high on a wall shouldn't be fitted near the floor.
Get the size right
Heating capacity in kilowatts comes before anything else on the spec sheet. Our sizing guide and size calculator give you a starting figure.
Compare efficiency, like for like
EECA's advice is to compare units of the same kW size. Read the Cold zone stars and the yearly kWh figure, explained further down.
Read the warranty conditions
Brands set rules about who installs and services their units. They're far easier to meet from day one than to discover at claim time.
Which type suits which room?
| High-wall | Floor console | Ducted | |
|---|---|---|---|
| Where it sits | High on a wall, near the ceiling | On or just above the floor, against a wall | One unit in the ceiling space or under the floor, with vents in each room |
| Good for | Single rooms and open-plan living areas | Anyone who'd struggle to reach a high unit to clean it | Several rooms, with little to see but the vents |
| Filters | Consumer NZ says they can be hard to reach, though some models self-clean | Consumer NZ calls cleaning them a breeze | Ask where the filter sits and how you'll get to it |
| Watch for | Tucked in a corner, it may only heat part of the room (BRANZ) | Furniture in front of it blocks the airflow (Consumer NZ) | Long or bendy ducts, or ducts through uninsulated space, can lose more than 30% of the heat (BRANZ) |
Ceiling cassettes and multi-room systems
A ceiling cassette either hangs off the ceiling or sits flush in it. Consumer NZ says it's handy where wall space is at a premium, but its filters are as awkward to change as a high-wall unit's.
A multi-room heat pump (a multi-split) runs several indoor units from one outdoor unit. Each indoor unit can have its own remote, but Consumer NZ notes you can't have one cooling while another heats. Mitsubishi Electric NZ adds that long pipe runs and extra bends reduce output, so a multi-room or ducted specialist will look at the pipe routes and the ceiling space before suggesting a layout.
A ducted heat pump usually recirculates the air already in the house, BRANZ says, with no fresh air supply. If damp is part of the problem, plan home ventilation as a separate job.
How to read the Zoned Energy Rating Label
Models new to the market since 1 July 2021 carry the Zoned Energy Rating Label, which EECA regulates here. The whole of New Zealand is in the Cold zone, so that's the part of the label to read.
Red stars show heating efficiency and blue stars cooling. Consumer NZ says the ratings run from 0 to 10, including half stars, and EECA's rule is simple: more stars, more efficient.
The kWh per year figure estimates the electricity the unit may use in that zone, and lower is better. EECA says it's only an indication, because every household runs its heat pump differently.
The label also gives the heating output at 7 degrees and 2 degrees outside. In a frosty area, give the 2 degree figure as much weight as the stars.
Older stock may still carry the previous Energy Rating Label. EECA says its stars and the new label's stars can't be converted, so don't weigh one against the other.
Cold winters and inverters
BRANZ says inverter systems are more commonly installed, being roughly 30% more efficient than fixed speed ones.
If your winters bring hard frosts, Consumer NZ suggests looking for a better low-temperature score in its test results. Pulling heat from near-freezing air takes more work, and de-icing the outdoor unit uses extra energy.
Where both units go
Indoors, Consumer NZ suggests placing a high-wall unit so its airflow reaches as much of the room as possible, but not right where you sit, so you're not getting fan noise and a draught in your ear. BRANZ adds that doorways and the likely furniture layout should shape the spot.
Outdoors, BRANZ says heat pumps are most efficient when the gap between indoor and outdoor temperatures is smallest, so it suggests the warmest spot, such as a north or west facing wall. Mitsubishi Electric NZ warns that units under houses or decks, or anywhere airflow is cramped, can create their own microclimate.
Then think about who's on the other side of the fence. Consumer NZ says the outdoor unit can be quite noisy, and noise limits sit in each council's district plan. Our consents and noise guide explains why that matters even when no building consent is needed.
Near the sea, or in a geothermal area, ask about corrosion protection before you settle on a model. Black Diamond Technologies says Mitsubishi Electric units in corrosive environments must be assessed and protected before installation, and Samsung NZ's warranty excludes damage from salt spray and other corrosive conditions.
Warranty conditions to check before you choose
- Who must install it. Rinnai NZ says installation must be by a Rinnai accredited installer.
- How often it must be serviced. Gree NZ's warranty card says the warranty is void without maintenance at intervals of no more than 12 months by a qualified refrigeration and air conditioning tradesperson.
- What counts as maintenance. Samsung NZ's warranty excludes damage from failing to maintain the product, and names the annual service and filter cleaning.
- Where the unit came from. Black Diamond Technologies only covers Mitsubishi Electric units it sold in New Zealand, not ones imported by an individual or another distributor.
- Corrosion cover, if you're near the coast or in a geothermal area.
- Your Consumer Guarantees Act rights apply whether or not there's a warranty, and a business can't sign them away.
What you can decide, and what an installer works out
You can
- Which rooms you actually heat in winter.
- Rough room measurements and ceiling heights.
- The Cold zone stars and kWh figure on each label.
- How close the outdoor spot is to bedrooms, yours and the neighbours'.
- The warranty conditions for each brand you're offered.
Leave to a licensed installer
- Sizing each room from its heat loss.
- Checking the outdoor spot has the clearances the maker asks for.
- Corrosion protection where it's needed.
- Refrigerant pipework, and the electrical connection by a registered electrician, who gives you a Certificate of Compliance.
Questions to ask before you settle on a model
- Which type would you put in this room, and why not the others?
- What's its heating output at 2 degrees outside?
- How many red stars does it get in the Cold zone?
- Where would the outdoor unit go, and how far is that from a bedroom?
- What does the warranty need from me, and do you service this brand?
What we'd do
If it were our home
We'd start with the rooms, not the brochure. We'd shortlist units of the right size with good Cold zone heating stars and a 2 degree output that holds up, and we'd pick the outdoor spot before the model. Then we'd read the warranty conditions before signing, because an annual service nobody mentioned is an easy way to lose cover.