Many New Zealand houses have issues with draughts. Draughts are undesirable because they basically let your nice warm air escape out of the house. Draughts can appear in a variety of areas, but most commonly around windows and doors.
Kneel down and have a look under each of your outside doors. These can be covered with a door brush or a door seal (on the inside and outside surfaces respectively).
To locate air leaks around windows, pass a stick of burning incense around your windows on a windy day. Draught stripping your windows is cheap.

 

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