How do you make sure you purchase the right heat pump for your home? How do you balance heating and running costs? Lets find out!

Everyone loves a heat pump! We’ve had a run of frosty mornings lately and there’s nothing better than to turn the heat pump on and fill the room with warm air. Its a life saver!

But, in a world where there are so many choices, you need to make sure that you get a heat pump that is not too big, not too small – just right!

And, while heat pumps are more efficient than electric heaters, they are not all equal. Some cost a lot more to run than others.

To help us understand the issues involved, lets first look at how a heat pump works, then we will define a few terms.

How a Heat Pump Works

Heat pumps work in the same way your refrigerator does, but in reverse. You may have noticed that the back of your refrigerator is warm. That heat is coming from inside your fridge. An evaporator coil extracts warmth from the air inside, and transfers it out into your kitchen through the condenser coil in the back.

The same things happens with your heat pump.

A heat pump has two units: one inside your home, and one outside. Because it is outside all year long in New Zealand’s harsh conditions, it is critical that you have a heat pump that has been manufactured to last for years.

You will also want the best warranty to protect against any defects in parts, materials and factory workmanship.

The outdoor unit absorbs heat energy from the air outside your home – even on a frosty New Zealand winter morning. Due to dust and other pollutants moving around your home, it is vital that your heat pump has excellent filters to remove all unwanted and unhelpful particles from entering your home – and your lungs.



Heat energy (not air) is transferred from outside the house to the inside

This heats up the refrigerant within the outside unit which is then transferred to the inside unit. This process uses energy, and not all heat pumps are made equal. You will want a heat pump that has a reputation for being energy efficient.

When the inside unit draws your living room air over the hot coolant, it increases the air temperature. This cycle is repeated until the air in your home get to the temperature you desire.

In summer, the two units switch roles and heat energy is transferred from inside the house to the outside, leaving your room cooler.

What do all the terms mean?

When it comes to choosing a heat pump it is helpful to understand a few terms:

Heating Output – how much heat will be generated. Measure in Kilowatt (kW), it is important to make sure that the kW matches the size of the room. As a point of reference, the 3.2 kW heat pumps in the chart below are among the smaller you can purchase, and will likely heat a small room. Other compact models will go up to around 10kW.

Cooling Output – how much cool air will be generated. It is usually different to heating output and so you need to choose a heat pump that meets both your heating and cooling requirements, or prioritize whichever is your greatest need.

Energy Rating (Cooling) – in New Zealand this is shown using a star system, as seen below. the more stars, the more energy efficient, with 6 stars being the best rating.

High Wall – Heat pumps can be installed near the ceiling on an internal wall. McClelland Refrigeration suggest that High wall heat pumps have dominated in recent decades as they can be cheaper to purchase, easy to install and do not clutter your floor space.

Floor Console – Floor mounted consoles are used in homes that cannot work with a high wall, such as homes with tall windows. Floor console heat pumps can be more expensive than high wall heat pumps, but they offer an excellent alternative to a high wall unit, when wall space is limited or undesirable. As they are mounted low on the wall they are very good at dispersing the heat they generate through the room at a level you will feel.

Putting it into practice

To illustrate these terms, the following chart compares the energy rating of three heat pumps.

This chart is supplied by Gen Less, a government agency dedicated to mobilising New Zealanders to be world leaders in clean and clever energy use. Gen Less is supported by EECA (the Energy Efficiency and Conservation Authority).

They are all 3.2 kW high-wall heat pumps, measured at 6 hours use per day. There are many models available in the NZ market – these are simply three well-known brands with examples of small heat pumps.

You can see from the chart below that:

  • The Hitachi heat pump has the best energy rating of the three, with 5.5 stars.
  • The higher energy rating means lower operating costs at $112 vs $119 for the Fujitsu.
  • The Hitachi and Mitsubishi provide more cooling than the Fujitsu.

GenLess tool for comparing heat pump energy ratings


This is not to suggest that one is necessarily better than the other. Its simply that you need to select the heat pump that matches your needs.


Tip #1: Decide which rooms need heating

This is perhaps the easiest question to answer.

Heating an entire home requires a larger solution than heating the office.

If you already have a log burner but want to heat the end bedrooms, then you may only need a couple of individual units.

Electricians in colder climates like Christchurch or Dunedin suggest you may want to select specific areas to heat.

Clearly, the larger the area you wish to heat, the greater the cost of the system you need to install. However, you may save a lot of money over the long term by using a heat pump compared to other heating solutions.


Tip #2: Choose the right type of heat pump

This relates to the previous tip. The area you want to heat will go some way to determining which solution you need.

If you only want to heat your living area, then you may find that a high-wall or floor console heat pump will do the job. If you also want to heat one or two bedrooms, you may add a smaller unit to each bedroom.

But if you want to heat your entire home, ducted in-ceiling aircon may be more effective. It’s the same technology but on a larger scale.

Ducted Heat Pumps

The benefit of ducted aircon is that the main units are hidden in the ceiling, so you don’t need to install multiple units on your wall. Easier, tidier, and looks much nicer.

However, it is important to note that this will heat every room to the same temperature. If you want more each room to be individually climate controlled, multiple small units will do that for you.

Multi-Zone Heat Pumps

A multi-zone heat pump allows you to heat or cool up to six indoor spaces with a single outdoor unit. You can control the temperature for each individual area, which could be an improvement on a ducted solution.

multizone heat pump

A multizone heat pump


Tip #3: Choose the right sized heat pump

Gen Less recommend that when choosing a new heat pump, it’s very important to select the right sized unit for the room or house.

We aren’t talking about the physical measurements of the unit, but how much heating or cooling it can produce (kW).

Sounds simple right? Measure the room and choose the relevant heat pump. Sorry… its not that easy.

  • Room size is a very important factor, as the larger a room is, the larger the heat pump needed. Bear in mind that room size takes into account ceiling height too.
  • It is also important to consider how well insulated the room or house is. A poorly insulated house will lose heat quickly and require more heating from the heat pump. Good insulation requires less.
  • Where do you live? It is highly likely that Wanaka will need more heating than Whangarei.
    heat pump regional guide

    Hitachi recommend different models for different regional temperature zones.

  • As mentioned above, are you buying the unit primarily for heating or cooling… or both?
  • Is the room facing north or south? How does that effect the temperatures you are dealing with?
  • How big are the windows? Are they single, double or triple glazed?
  • You could even factor in the building materials of the home, to se if there is any heat likely to be stored in concrete or bricks

So there you go

We can do all the hard work for you, so If you need any help or want to discuss the choices available, give the team at Jenco Electrical a call on 0800 453 626

Jenco Electrical are registered master electricians in Auckland, who can help you with all residential and commercial electrical needs. Jenco Electricals provides prompt, reliable and highly organised electrical services that will get the job done right and on time in Auckland CentralWest AucklandSouth Auckland & North Shore.