The best heat pump settings for a NZ winter

A heat pump is one of the cheapest ways to heat a room with electricity, but the settings you pick matter. The same unit can run efficiently and quietly, or it can burn power on heat that leaks straight out through single glazing. This guide covers the settings that make the biggest difference in a New Zealand winter, based on advice from EECA and Consumer NZ.

What temperature should I set my heat pump to in winter?

Set it between 18°C and 21°C. EECA's advice is to keep the thermostat at 20°C or 21°C at most, and Consumer NZ suggests around 18°C is enough for many rooms. Every degree above that makes the heat pump work harder, raises your power bill and, on cold mornings, makes the outdoor unit ice up faster.

The number on the remote is the temperature the indoor unit measures near the ceiling, where warm air collects. If the room still feels cold at 20°C, raising the setpoint to 25°C rarely fixes it. Check the fan speed and louvre direction first, close doors to unheated rooms, and ask whether the unit is big enough for the space. Our sizing guide explains how to check.

Should I leave my heat pump on all day?

In most New Zealand homes, no. Consumer NZ's advice is to run the heat pump only when you are home, and EECA recommends using a timer rather than leaving it running. Heat pumps warm a room quickly, and a typical house loses heat through its walls, windows and gaps all day, so keeping an empty house warm uses more energy than reheating it later.

The exception is a very well sealed home: modern airtight construction, insulation well beyond the Building Code minimum, double glazing, thermal curtains and a heat recovery ventilation system. In a house like that, heat leaks out so slowly that holding a steady low temperature can make sense. If your home is an older villa or a 1970s weatherboard house, it almost certainly is not in that category.

Why shouldn't I use auto mode?

Auto mode lets the heat pump decide whether to heat or cool to reach the setpoint. EECA warns that auto can switch the unit into a mode you did not expect, so on a sunny winter afternoon it may start cooling a room that the sun has warmed, then heat it again in the evening. Pick heat mode in winter so the unit only ever adds heat.

Which way should the louvres and fan point?

Point the louvres down when heating. Warm air rises, so aiming it at the floor spreads heat through the room before it collects at the ceiling. Leave the fan on auto for everyday use: it runs faster while the room warms and slows once it reaches the setpoint. Use high fan for a quick warm-up and quiet or low in bedrooms.

• Louvres down or angled towards where people sit when heating. Up or level when cooling in summer.
• Avoid blowing straight at a sofa or bed. Draughts make a room feel cooler than it is.
• Keep furniture and curtains away from the front of the indoor unit so air can circulate.
• Close doors to rooms you are not heating so the heat stays where you want it.

What does dry mode do, and when should I use it?

Dry mode, often shown as a water droplet, runs the heat pump gently to pull moisture out of the air without much heating or cooling. It helps on mild, damp days when windows fog and washing will not dry. EECA notes dehumidifying uses less energy than full cooling in summer. On a cold day, use heat mode: warm air holds more moisture and a warm room is easier to keep dry.

Why does my heat pump stop heating on frosty mornings?

It is defrosting. When the outdoor air is near freezing and humid, ice builds up on the outdoor unit's coil. The heat pump pauses heating for a few minutes, melts the ice, and then starts again. You may see steam or water coming from the outdoor unit. This is normal, and Consumer NZ explains that cold, humid conditions around 0°C are when heat pumps work hardest.

• Keep the outdoor unit clear of leaves, snow, long grass and anything stacked against it.
• Make sure defrost water can drain away and will not freeze into an ice slab on a path.
• A lower setpoint means shorter, less frequent defrost cycles.
• If defrosting happens constantly or the unit trips, get it checked. See our servicing page.
• In the coldest parts of the country, a heat pump with good rated output at low temperatures matters. Our brand guides set out what each brand publishes about its NZ ranges.

Is Wi-Fi control worth it?

For many households, yes. Consumer NZ lists skipping Wi-Fi as one of the common heat pump buying mistakes, because app control lets you start heating on the way home and switch off a unit you left running. If your heat pump does not have it built in, many brands sell a Wi-Fi adapter. Ask for it when you compare quotes, since adding it later can cost more.

How much do these settings save?

It depends on your home, your unit and your power price, so treat any single figure with caution. Consumer NZ's running cost estimates range from under $200 a year for a small 2.5 kW unit to about $1,000 for a large 10 kW unit. The national average power price was about 42c/kWh in May 2026 (MBIE). To estimate your own costs, read the running costs guide.