[ClumsyPilot]

> renovating generally means reducing breathability of the house itself, which, combined with the temp difference, means condensation/mold problems

Look up Passivehouse standard, modern construction can make extremely effocient buildings, but it relies on the building being nesrly airtight, so it must have ventillation.

'Natural' ventillation naturally steals your heat, it's incompatiable with efficiency