We went from a 1920s bungalow to a brand new build in Rolleston earlier this year and were surprised by the amount of condensation, our windows were soaked each morning, we must be hot sleepers and we weren't opening the windows on really cold mornings. At the recommendation of some of the people here on GZ and doing lots of research we ended up going with a Cleanaire balanced heat recovery system and it's been brilliant, it's completely sorted the condensation problem. The house is 235m2 and the system was $6.5K installed.
Interesting. Our place is 4 years "new" (or old). We have two heat pumps that run pretty much 24x7 in winter and the mjaority of windows closed (ony bathroom windows open slightly). We are a family of 4 with 3 being home during the day (plus 2 dogs).
The only room Ive ever seen condesation is in my sons rooms and only if he shuts the door and all the windows overnight. If he leaves one of the windows open a crack its fine.
Other than that we dont seen any condensation. This is in Wellington. So maybe its a factor of being further south?