Summer is just around the corner, which means it’s a good time to start thinking about your cooling options. For heat pump owners, the good news is you probably won’t have to look too far, given that most models also come with the capacity to cool. When using a heat pump’s cooling mode, it functions like a traditional air conditioner, helping to keep your household cool and comfortable during the warmer months.
Types of heat pumps
There are four types of heat pumps typically available:
- Single split systems – the type most commonly used in New Zealand, with an outdoor unit connected to an indoor unit, which heats the room it’s installed in.
- Multi-split systems – comprise one outdoor unit which connects to multiple indoor units, heating different rooms in a house.
- Ducted heat pumps – are a type of central heating system that blows heated air through concealed ducts into multiple rooms.
- Portable heat pumps – small units on wheels that can be used around the home, wherever heating or cooling is required.
Typically, single and multi-split systems are available as a floor console, ceiling console, ceiling cassette, or high-wall unit. Ducted heat pumps, which are typically more expensive, are well hidden and a good option if you don’t like the look of a heat pump unit. However, they can be more intrusive to install.
Factors to consider for heat pump size
When it comes to sizing up a heat pump unit for a room, there are a number of factors to take into consideration including room size, orientation and insulation.
Room size
Each room in your home will have different air conditioning capacity requirements. Generally speaking, you’ll need about 0.12kW to 0.15kW of power per square meter of floor area. This is calculated by multiplying a room’s length in meters by its width in meters. You’ll also need to take into account ceiling heights in your calculations, as rooms with higher ceilings will always need more energy to cool.
→Related article: How Much Are You Paying For Power? Average Electricity Costs per kWh in NZ
Orientation
The orientation of your home, as well as the size and orientation of windows and glass doors in each room, will impact your choice when it comes to settling on the right heat pump size. Do you know which rooms the midday sun hits? As a general rule, southern-facing rooms will be cooler which means they won’t require as much cooling capacity as north-facing rooms that receive sun for the longest period of the day. The ideal orientation for your home will also depend on your climate zone.
Insulation
Insulation is a material located within your home’s walls and ceilings designed to slow or prevent heat flow. In other words, insulation makes your home thermally efficient − it helps to keep heat inside your home in winter and outside your home in summer.
You’ll need to consider your home’s level of insulation when deciding which air con size you need, because if your house is poorly insulated, your heat pump will need to work much harder to keep the place cool or warm.
How to calculate heat pump size?
There are online calculators that allow you to figure out the cooling or heating capacity you need for your home. Depending on which calculator you use, the capacity takes into account a variety of factors such as:
- Type of heat pump
- Whether the roof is insulated
- Window and window glass type
- Room height
- Room width
- Room length
- The amount of sunlight the room is usually exposed to
- Whether the room directly faces the afternoon sun
- Climate
Some aircon installers also provide online calculators on their websites and offer a few common size options if you’re unsure of measurements or just want a quick guesstimate before diving into specifics.
Room size |
Room examples |
Heat pump kilowatt capacity |
| 10-25m² | A small kitchen, bedroom, study, small lounge, small office | 2.5kW |
| 25-30m² | Bedroom, small lounge, small room with a high ceiling, office, mid-sized kitchen | 3.5kW |
| 35-60m² | A large bedroom, bedroom with an ensuite, mid-sized lounge | 5-6kW |
| 60-80m² | Large lounge, large open plan area, small shop, office | 7-8kW |
General guide only
How much do heat pumps cost?
Heat pump units vary in price depending on brand and size. Portable models start around $800, while wall-mounted models are priced between $1000 and $4000. However, the cost to install multi-split heat pumps and ducted systems are only limited by the size of your home. And, of course, you must pay for professional installation for all permanently fixed heat pumps, which can increase the cost considerably.
How much do heat pumps cost to run?
How much your air-con will cost to run will come down to a number of factors such as the size of the unit, how long and how often you run it and the specific type of air-con. It will also depend on your electricity provider and the rates that they estimate and offer.
Compare electricity providers for free with Canstar Blue!
Which type of heat pump should I buy?
Which type of heat pump you buy will come down to a number of factors. First will be the size of your home and the rooms you need to heat within it. If you have a larger home, ducted heat pumps could be ideal, whereas if you live in a smaller apartment a portable unit might be the best option. You will also need to consider the costs and construction work needed to retrofit any multi-heat pump systems into your home.
For more on New Zealand’s favourite heat pump brands, just click on the button below.
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About the reviewer of this page
This report was reviewed by Canstar Content Producer, Caitlin Bingham. Caitlin is an experienced writer whose passion for creativity led her to study communication and journalism. She began her career freelancing as a content writer, before joining the Canstar team.
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