> Asked by the tabloid BILD-Zeitung what feelings Germany awakes in her, Angela Merkel once famously replied, 'I think of well-sealed windows! No other country can make such well-sealed and nice windows [dichte und schöne Fenster].'
https://nybooks.com/articles/2013/08/15/new-german-question/
It really doesn't matter how fast you replace the air. If you let in the cold air then you need to warm it up.
What you actually do is a compromise between energy conservation and properly ventilated room as for the morning the room will be filled with high concentration of CO2 and humidity (from your breathing and sweating) and you more than often end up with bad sleep and headache.
Constant proper mechanical ventilation is the key for better sleep and health when windows are goods as German windows (some other European countries make good windows too).
Ventilating quickly is preferable to ventilating slowly. Heat transfer through materials is comparatively slow. That means that exchanging the air in an instant retains the heat in the walls, furniture,… exchanging the air slowly allows heat from materials to „leak out“ as well.
The best way is ventilation through heat exchangers.
If you ventilate through a heat exchanger when inside and outside are different temperatures, you can have more fresh air more of the time while saving energy.
there are some potential issues if outside temp is higher and it's humid tough. these systems can cause mold.
Moreso than the shock ventilation method?
If there's worrying amounts of moisture, we could go ahead and say we'll do the same amount of air with the heat exchanger. Is that worse for mold potential than the alternative?
Because without doing the math on that, such a statement is absolute pointless.
I wouldn’t be surprised if the heat exchangers save 1000x the energy that they consume.
How much money do you spend on powering the vent in your laptop vs how much money do you spend on heating?
But the burden of proof is on the one that’s making the extraordinary claim.