Heat pumps
The right information is essential when choosing a heat pump.
Find the right heat pump for your needs.
A heat pump can cool a room as well as heat it, allowing you to use it as an air conditioner. We analysed the performance data of virtually every heat pump on the market and developed a step-by-step guide to help you choose the right model for your home. We’ve also got all the hottest tips on the most effective ways to use them.
Heat pumps vs heaters
Before you begin choosing a size, style or model of heat pump, you need to consider their pros, cons and cost-effectiveness.
Pros
▲ Warm, dry and comfortable
Heat pumps can provide a level of all-round comfort not easily obtained by plug-in electric heaters. They can quickly bring a room up to temperature and then maintain it.
▲ Lower heating costs
If you install a heat pump and keep your home about as warm as you do now, you could save a considerable amount in heating costs. But some of our members with heat pumps tell us they use their units to keep their homes warmer than before, so their heating bills haven't dropped by much.
A large heat pump (10kW+) might cost as much as $800-900 per year to keep you warm while a small heat pump (2kW) can cost below $200.
▲ No gas charge
If you install a gas heater, you'll have to pay a gas connection charge (often around $40 per month) all year round, for a heating appliance you use for less than a whole year.
▲ Dehumidifying
If you run the heat pump in “cooling” or “dry” mode. It’ll remove moisture from the air. Bear in mind that water removal is modest compared to purpose-built dehumidifiers.
▲ Air filtering
Most heat pumps incorporate a washable filter unit that removes dust and particles from the air. This could be an important feature for people with asthma and allergies. The filters need regular cleaning to keep the unit working at maximum efficiency. Some have a deodorising function as well.
▲ Cooling
A reverse-cycle heat pump is the only type of home heating system that can both heat and cool a room.
Cons
▼Noise
Whirring fans can be very annoying. Fans run in both the interior and exterior units all the time they are switched on. The fan in the inside unit of a heat pump should produce little more than a low hum in low-speed mode, but the compressor plus fan of the outside unit can be quite noisy. Also, consider the impact on neighbours if the outdoor unit must be mounted near their sleeping areas.
▼ Not so good in low temperatures
Extracting heat from outdoor air gets more difficult as the temperature drops. Sometimes, especially on frosty nights, exterior heat pump units freeze up and have to stop working for several minutes while they defrost. If this is important to you, check our database for heat pumps with a higher “Low temperature score”.
▼ Draughts
Circulating air can cause draughts – which means you need to think about where to place the unit. You don't want one on the wall just above your favourite armchair as passing air can make you feel chilly.
Types of heat pump
Split systems
Split systems work well in a large lounge or the main living area of an open-plan home.
A split system has an exterior compressor unit connected to an interior ceiling or wall unit by copper pipes (for the refrigerant) and wiring.
The interior unit is made up of electrical/electronic controls and a fan which circulates air over finned tubing for either cooling or heating, depending on the setting of the unit.
Much of the installation cost of split systems comes from running the pipes and wires from the exterior to the interior locations.
Multi-split systems
In a multi-split system the exterior unit connects to more than one interior unit. Often, one interior unit is located in the living space and another in the bedroom area.
Multi-split systems can be cheaper than having separate external units for different parts of the house, but there may be extra installation costs from longer piping runs and some extra control complexity.
The interior units can have separate controllers – but it is not possible to have one interior unit cooling while the other is heating.
Ducted systems
These have a single, large capacity interior unit mounted in the ceiling space, or under the floor. The heated (or cooled) air is pumped through insulated ducts to ceiling or floor outlets in many or all of the rooms in the house.
Ducted systems have the least visual impact of any heat pump system – just small flush vents in each room.
Because there is some heat loss from ducts themselves, they are slightly less efficient than other systems. They are also expensive to install.
How to maintain and clean your heat pump
Getting the best out of your heat pump only takes a vacuum cleaner and a few minutes of your time.
Internal unit position
The options are high wall, ceiling, low wall or floor.
High wall mounted heat pumps
High wall units are the most common heat pumps in New Zealand. They're usually long and thin, are mounted close to the ceiling and circulate enough air to heat a room evenly.
They should be located so the airflow can reach as much of the room as possible, but not close to where you'd normally sit (so you don't have to put up with fan noise in your ear while you're watching TV).
High wall units can cause the surrounding wall and ceiling area to become covered in dirt and grime, and the high location makes filter cleaning difficult, particularly for the elderly and disabled. Some makers offer self-cleaning filter models to solve this problem.
Ceiling mounted heat pumps
These either hang off the ceiling or are fitted into the ceiling. One advantage of ceiling units is they can be installed where wall space is at a premium. They have the same dirt and filter changing drawbacks as high wall units.
Low wall or floor mounted heat pumps
These sit on the floor, alongside a wall. They must be sited so furniture does not obstruct the airflow, and should be located where they can distribute the warm air to as much of the house as possible. Filter cleaning is a breeze.
Floor vs ceiling units - which is better?
Some suppliers suggest that for the best heating effectiveness, the internal unit should be floor mounted. This could be particularly important if you have high ceilings. Hot air rises and, if your unit is up on the wall, all your lovely heat could end up keeping the roof warm. But floor-mounting may not be possible. Also, we're not saying a wall-mounted unit won't work. You should carefully discuss your options with the supplier before you sign up.
For best cooling effectiveness, a unit mounted high on the wall or on the ceiling is best. This is because cold air falls.
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Which heat pumps are most reliable?
We ask thousands of Consumer members about their products to find out which brands are most reliable and satisfying to own. The results are available to members and Digital Pass holders.
What size heat pump?
Our table allows you to estimate the capacity of heat pump you’ll need to maintain a comfortable temperature.
The table assumes a standard ceiling height of 2.4m. If you have high ceilings, adjust the estimates up.
Features to look for
Most heat pumps come with variable fan speeds, timers and dehumidifying modes. But there are other features to look out for.
WiFi
WiFi eliminates the sometimes complicated heat pump remote from the equation and allows you to easily set timers and control the heat pump from your phone. If you can get this feature on your heat pump, you should go for it.
Ionisation
Heat pumps will never be as good at filtering as an air purifier with a HEPA filter. But if you suffer from allergies, a heat pump with ionisation will help remove particles from the air.
Human presence sensor
When active, this will detect if someone is in the room and keep working. Some models will even send warm or cool air towards them. If no one is detected, the heat pump can scale back it’s work and use less power.
Is it more efficient to leave heat pumps on 24/7 or to turn them on when heat is required?
We answer your frequently asked questions about heat pumps.
Energy Rating Labels
The Energy Rating Label has a scale of stars to show how energy efficient a model is, compared to other models of the same size/capacity.
More stars = more energy efficient.
The energy consumption figure is in kilowatt-hours (kWh) and you can use this figure and the cost (tariff) from your latest power bill to calculate how much this model will cost to run. The MBIE-reported national average cost of a kWh in New Zealand is 29¢.
Lower kWh = cheaper to run.
Heat pump annual energy consumption in kWh is based on a complex methodology which takes into account the heating load, capacity, and efficiency at different temperatures as well as climate data.
You should only compare star ratings of heat pumps with the same or similar capacities.
For information on energy ratings and how to use them, see our Zoned Energy Rating Label (ZERL): what you need to know article.
Other ratings
COP (Co-efficient of Performance)
The COP is a technical calculation of heating efficiency which is used in the methodology for calculating star ratings. For heating, a good unit has a COP of 3 or more. The heating COP can be reduced by cold temperatures because de-icing takes extra energy.
Energy efficiency ratio (EER)
This is the calculated cooling efficiency, and is also used in the star rating methodology. The higher the rating, or the more stars, the better. An EER of 3 or more is good.
We've assessed 266 heat pumps.
Find the right one for you.
