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Heating

The truth about 'one big heat pump heats the whole house'

It's the most-quoted line in the trade and it's mostly wrong. Heat doesn't move through walls, doors and corridors the way installers promise.

A 7.1 kW heat pump in your lounge is excellent at heating your lounge. The bedrooms down the hallway? Two doors and a temperature drop of 5–8 °C, even with the lounge unit cranking.

NZ research from BRANZ shows that whole-of-house heating from a single high-wall split typically achieves around 16 °C in the bedrooms when the lounge is at 22 °C. WHO recommends 18 °C minimum in living and sleeping spaces.

When does a single unit work?
  • Open-plan, single-storey homes under 90 m² with very good insulation
  • You don't mind the bedrooms being cooler
  • You're using a floor console or ducted system, not a high-wall
When you really need multiple zones
  • 3+ bedrooms you actually want warm
  • Two-storey homes
  • Old villas with internal walls and corridors

Use our Whole House mode to see whether you need one big unit, several singles or a multi-split.

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