Does a heat pump bring fresh air in from outside?

No. A normal heat pump recirculates the air already in the room through its filter and coil. Only refrigerant travels between the indoor and outdoor units, so nothing new comes in from outside. For fresh air you need an open window or a ventilation system, which is a separate product.

Can a heat pump cool one room while heating another?

Only if they're separate systems. A multi-split with one outdoor unit runs every indoor unit in the same mode, all heating or all cooling at once. You can't heat the bedroom while cooling the lounge off a single outdoor unit. [Single-room vs multi-room heat pumps](/guides/single-room-vs-multi-room-heat-pumps/) goes through the trade-offs of each setup.

Do heat pumps work in very cold weather?

Yes, though they put out less heat as it gets colder outside. Some models keep heating down to minus 15°C, and a few are built to hold their full rated output that low. Check the minimum operating temperature in the specifications, and look at the 2°C heating figure on the label.

Is a heat pump cheaper to run than a bar heater?

For the same heat, yes. A heat pump moves heat rather than making it, so a good one puts out around three to four kW of heat for every kW of power it uses. A bar heater turns one kW of power into one kW of heat, so it takes far more power to warm the same room.

Why does the energy label call it an air conditioner?

The government's Zoned Energy Rating Label uses the name air conditioner, even though in the NZ residential market these machines are typically known as heat pumps. Same appliance, different label. Every New Zealand address sits in the Cold zone on the label's map, so compare the Cold zone stars for both heating and cooling when you're shopping.

Heat Pump vs Air Conditioner: What's the Difference in NZ?

In a New Zealand home, a heat pump and an air conditioner are usually the same machine. What much of the world sells as an air conditioner, Kiwis buy as a heat pump, because heating is the part we actually care about. The government’s energy label uses the name air conditioner, even though in the NZ residential market these machines are typically known as heat pumps.

The proper name for the kind that does both is a reverse-cycle air conditioner. It heats in winter and cools in summer, and it’s the only common home heating system that can do both.

How a heat pump heats and cools

A heat pump doesn’t make heat. It moves heat from one place to another, using a refrigerant that runs in pipes between an indoor unit and an outdoor unit.

Cooling: the indoor unit draws warm room air over a cold coil. The refrigerant soaks up that heat and carries it outside, where the outdoor unit releases it. Cooler air goes back into the room. That’s the job an air conditioner does.

Heating: a valve reverses the flow. The outdoor unit pulls heat out of the outside air, even on a cold day, and the indoor unit releases it into the room.

Because it moves heat instead of making it, a good heat pump gives out several times more heat than the electricity it uses. That’s why it’s one of the most efficient ways to heat a home with electricity.

What is a cooling-only air conditioner?

Some air conditioners can only cool. You’re most likely to meet one as a portable air conditioner, the box on wheels with a hose out the window. A single-hose portable blows cool air out the front, so you feel cool sitting in front of it, but it doesn’t cool the room overall. That’s why single-hose portables get zero stars on the NZ energy label. Double-hose portables can heat or cool a room, and they can earn stars.

If you want a fixed system that keeps you warm in winter and cool in summer, you want a reverse-cycle heat pump. Which, in New Zealand, just means a heat pump.

Heat pump, air con, split system: the words explained

Installers, shops and brands use a mix of terms for the same few things. It can feel like they’re describing four different machines. They’re not.

Heat pump: the everyday NZ name for a reverse-cycle air conditioner.
Air con / aircon: the same machine. Brands often write “heat pump / air conditioner” on a single product.
Reverse-cycle: a unit that can switch between heating and cooling.
Split system: a heat pump with a separate indoor and outdoor unit, joined by pipes.
High-wall, floor console, cassette, ducted: the styles of indoor unit. See ducted vs high-wall heat pumps and floor console heat pumps.
Multi-split or multi-room: one outdoor unit running several indoor units.
Inverter: a heat pump that speeds up and slows down to match the heat needed, rather than switching fully on and off. Most modern units are inverters.
Heat pump hot water: a different appliance that heats your water, not your rooms. See hot water heat pumps.

→ Related: Single-room vs multi-room heat pumps

Do you need cooling in a New Zealand summer?

You might buy a heat pump for winter, but in a hot Hawke’s Bay January, a stuffy Auckland apartment or an upstairs bedroom under a tin roof, the cooling side earns its keep.

To cool well and cheaply:

Don’t set it freezing cold. A lower setting won’t cool the room any faster. It just uses more power. Around 23°C or a little above is comfortable for most people and keeps the power use down.
Point the vanes down a little. Cold air falls, so let it drop to where the people are.
Close doors to rooms you aren’t cooling, so warm air doesn’t keep seeping in.
Use a timer to start cooling before the afternoon heat builds, instead of fighting a hot room later.
For muggy days, dry mode can take some moisture out of the air. Whether heat pumps dehumidify covers when to use it.

High-wall units are better for cooling than floor consoles, because the cold air drops from up high. If summer cooling matters as much as winter heating, keep that in mind when you’re choosing.

Where should the indoor unit go?

The indoor unit decides when to stop heating or cooling by reading the room’s temperature. Put it in direct sun, beside a light fitting or next to a TV and it gets a false reading, and the room ends up warmer or cooler than you asked for. Keep it clear of furniture and curtains too, so the air can spread across the room. A good installer will talk you through the spot before drilling any holes.

What the energy label tells you about cooling

The Zoned Energy Rating Label shows three capacity numbers. The cooling figure is measured at 35°C outside. The two heating figures are at 7°C and 2°C. Size the unit on whichever job you’ll use most. In most of New Zealand that’s heating.

The label also has star ratings for heating and for cooling. All of New Zealand sits in the Cold zone on the label’s map, so compare the Cold zone stars. If the label shows noise levels, they’re measured at full power in cooling mode, so the unit is usually quieter than that. What size heat pump you need explains the heating figures in more detail.

Where to find a heat pump installer near you

Browse installers who fit high-wall heat pumps and other styles, or pick your town to see who works near you. For offices and shops, see installers who do commercial air conditioning.