> Most days, you can hopefully leave the windows open during the day and/or night. On smoky/hot/cold days you can run filters and ac/heat.

I'm in Toronto, Canada: our winters are -10C and our summers are hot-humid 30C.

* https://en.wikipedia.org/wiki/Toronto#Climate

Leaving windows open is not the preferred option for most of the year (though I grew up in a house with A/C, and only first experienced an abode with in in my 20s).

Further, more places are getting bouts of extreme weather:

* https://en.wikipedia.org/wiki/2003_European_heat_wave