In some countries, the windows are double-glazed. In some countries, the windows are triple-glazed. In New Zealand we are a hardy bunch, and unless you live in a fairly new house (or a house with fairly new windows) there’s a good chance you have single-glazed windows.
Yep. A single layer of glass between you and the chill of the winter beyond. Admittedly, our winters aren’t as cold as some places, but when flights head to Scott Base in Antarctica, New Zealand is where they leave from.