What size heat pump or air conditioner do I need?

December 02, 2022

It’s a question we get asked often, ‘what size heat pump do I need?’ And it’s a very important one to ask otherwise, you might just be throwing your money out with the heat…or cool air! By the way, we use the terms ‘heat pumps’ and ‘air conditioners’ interchangeably as the units we sell and install, do both. And we’re not talking about the actual physical size of the unit, but the heating and cooling output which is measured in kW.

If you need help, or don’t know where to start, then give the friendly G-Force customer service team a call on 0508 088 888 and they can help you find the right heat pump for your home.

www.consumer.org.nz have created the handy table below, that will give you a rough estimate of the capacity of heat pump you’ll need. Note, the table assumes a standard ceiling height of 2.4m. If you have high ceilings, adjust the estimates up. There are other variables to take into consideration as well like:

  • What’s the weather like where you live? e.g. does it snow regularly or never?
  • How old is your home’s insulation? Or maybe it’s not insulated?
  • How many rooms are you heating or cooling? e.g single, multiple rooms or the whole home?
  • How large are the rooms you want to heat & cool?
  • Do you have double-glazing on your windows?
  • How many people live in your home?
  • Does the room you want to heat get a lot of direct sun?

We’ve added some heat pump brands to the table that might be suitable, however we do recommend you talk to a specialist, like us, before deciding as we have an extensive range suitable for a wide range of budgets.

And remember, we’ll come and chat to you about your needs and provide a FREE quote. Once you decide which heat pump unit you’d like, we’ll come back and install it so you can sit back and enjoy the cool air in summer and warmth in winter.

Room sizeExample
capacity –
if insulated
capacity –
if not insulated
Small (up to 20 m2)Bedroom,
small kitchen
2 kW2-3kWDaikin Standard Heat Pump
Medium (20-40 m2)Bedroom with ensuite, small lounge2-4kW3-5kWDaikin Cora Heat Pump
Large (40-60 m2)Large bedroom, lounge, large kitchen4-6kW5-8kWRinnai Heat Pump Q-Series
Extra large (60+ m2)Open-plan areas, large loungeMore than 6kWMore than 8kWFern Carrier


At G-Force Healthy Home Solutions we’re all about making homes warmer, drier and more energy efficient for Kiwi families.

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