Heat Pump FAQ


Heat pumps are basically space heaters. They provide convenient, efficient, thermostatically-controlled heating that can be set to come on and off automatically at different times of the day.

The smaller versions are designed for a single room; the larger, for a whole house. It takes 20 to 40 minutes to bring a room up to temperature, after which the level will be maintained within 1 or 2 degrees.

How heat pumps work ?

A heat pump works by extracting heat from the air outside your house and bringing it indoors. It’s like a refrigerator in reverse. By trying to cool the world it can extract heat, or vice versa.

Use an old-style bicycle pump for a while and it will get hot. That’s because gas (air) is being compressed. Spray an aerosol can and the valve area will become cold. That’s because the compressed gas in the aerosol can is expanding.

Heat pumps (like refrigerators) have a system of pipes containing gas (refrigerant) that is continuously expanding in one part of the system and compressing in another. When the gas is being compressed, it gets hot. A heat pump’s exterior unit compresses the gas, then pumps it to the interior unit where the gas runs over a series of finned coils, giving off its heat.

The gas is then returned to the outside unit, where it expands and runs through another set of finned coils, which become cold. The cold gas is then recompressed and the cycle continues. For summer cooling, the refrigerant flow is reversed, so the interior unit becomes cool, while the exterior cold.

Heat pumps shift more heat than the electrical energy consumed in compressing the refrigerant and running the fans, making them highly-efficient methods of heating – up to 4 times as much in the right conditions.

Is a heat pump the same as a ventilation system?

No. A heat pump uses refrigeration principles to shift relatively large amounts of heat in or out of your home to warm or cool it. A domestic ventilation system shifts drier air from the ceiling space into the living space, and is designed to reduce condensation.

Should I use my heat pumps 24 hours a day?

No heating appliance should be used 24 hours a day. Clever use of a heat pump is using it as required. If you are not at home during the day, there is no need to run your heat pump during the day. In this situation, and with good insulation, a couple of hours in the morning and a few hours in the evening should suffice.

For example, when running a 3.2kW heat pump for about 8 hours a day you could expect to rack up around $30 in power usage per month. Compare this to running a similar wattage bar heater for the same period of time, which would cost you a whopping $120 per month!

Can a heat pump be programmed to operate automatically?

Yes. Most heat pumps will have a 24 hour timer which allows you to program your heat pumps operation for the day and some with 7 day timer.

If I turn my heat pump up to 28°C will it heat the room faster?

A heat pump should not be operated like a radiant heater. Turning your heat pump up to 28°C will not make the room warm up any faster. In fact, it will use more energy as the heat pump attempts to absorb energy to achieve this unrealistic temperature.

By setting the temperature to what is actually required, say 18-22°C in heating mode (a comfortable temperature during winter), the heat pump will respond in the most efficient way and will reach this quickly and continue to maintain it – without further adjustment. Using a timer to activate this temperature half an hour before you arrive home will mean you return to warm, cosy comfort.

What is “defrost mode”?

All heat pumps will perform a defrost cycle eventually when operating in cold winter conditions. The defrost mode removes ice build up from the outdoor unit. In defrost mode the heat pump stops heating for short periods.

Can I install a heat pump myself?

Installing a heat pump is a complex process and if it is not installed by a qualified installer, it will not be covered under warranty. All heat pumps must be installed by an authorised dealer to qualify for warranty. It is important that you protect yourself by getting your heat pump installed by a professional. Your installer will ensure you get; the correct heat pump and sizing for your geographical location and space, ensure optimal position of the heat pump, educate you on correct operation and provide a warranty for the system installed.

How do I know which size is best for the room I need to heat?

Every home is as individual as its owner in its requirements, choosing the wrong size for the room you need to heat can leave you cold and cost you more in power consumption.

Insulation and building orientation are important considerations when it comes to potential heat loss. For example; an older home with less insulation will lose indoor heat far quicker than a modern well insulated home. A bigger heat pump system would therefore be needed to overcome this heat loss.

In winter, when outdoor temperatures drops, the amount of heat a heat pump can produce lowers. Areas of New Zealand that experience sub zero temperatures will require a larger capacity heat pump (compared to a similar sized room in moderate climate).

Because of the technical nature of correct sizing, we strongly recommend that anyone in the market for a heat pump arrange an in-home consultation and quote, and ensure this is carried out by an authorised professional.

To get an idea of the size you will need for your home, click here to access our Heat Pump Selection Tool.

If I need to heat multiple rooms in my home, will I need multiple outdoor units?

Not necessarily. Multi-room systems (sometimes called multi-split systems) are an option. To achieve a warm home, you will often require more than one heat pump to effectively heat your whole home. A multi-room solution gives you the freedom to choose the most suitable heat pump for each room, i.e. super quiet heat pumps for bedrooms and larger capacity units for living areas. The great thing about multi-room, is that up to four indoor units can be connected to a single outdoor unit. So, you are not disturbing the outdoor aesthetics of your home. Correctly selected and installed multi-room systems can save you power and reduce extraneous noise.

Does a heat pump prevent condensation?

Heat pumps not only provide heating and cooling to your home, they also have dehumidifying benefits. In cooling mode, the room is automatically dehumidified as a function of the heat pump. In heating mode, the unit does not need to dehumidify as the warm air being circulated removes moisture in the room.

Dry Mode operates by cooling the indoor unit to gather moisture. In winter months, use “Dry Mode” once you have heated the room. The room will be kept with approx 2°C of the initial room temperature, ensuring a warm, dry home!

How often should I clean my heat pump?

Cleaning your heat pump regularly ensures optimum operation by reducing unnecessary power consumption, increasing efficiency and limiting exposure to condensation. We recommend cleaning your heat pump as often as every two weeks in order to utilise its full performance.

What does “back to back installation” mean” 

Indoor installed on external wall of a 2.4M stud house close to the ceiling and outdoor unit just at the back of the wall outside the house with a straight drop of piping. Outdoor placed on level ground on ground bases. Power taken from a nearby power point on the external wall if suitable.