[LeonM]

I don't understand why you are being downvoted, you raise a good point.

Based on some HN comment from a while ago I invested in a CO2 meter (they are still quite expensive for some reason). And I share the same experience, CO2 levels can raise rapidly indoors, but simply turning on ventilation or opening a window very quickly lowers CO2 contents.

Using the meter I found CO2 levels in my bedroom can become quite high at night. So I improved the ventilation in my bedroom, and in my case it helped me to achieve better sleep.

[anonyfox]

… and people make joke about us Germans need to do „stosslüften“ (opening all windows in parallel to get fresh air in fast).

also, are there really people that can (or even prefer!) to sleep with closed windows?! Only with AC blasting, right?

[balfirevic]

Yes, that's the only way to have nice cozy temperature throughout the year. Heating will be on during large part of the year, but during the summer AC will be on. Just working gently, though, no blasting.

I'd love to have ventilation with heat exchanger, but that's basically unheard of where I live.

[cultureswitch]

I can't sleep with either AC, simple ventilation or windows open. Too much noise. In rural environments too, just a single cricket is capable of keeping me awake.

Sometimes in very hot weather I do leave the windows open at night but it's due to heat, not air quality.

[heipei]

Try sleeping with earplugs. I started doing it out of necessity, and it was awkward at first, but once I got used to it was really life-changing. Sleeping with plugs in feels like being embraced by silence and darkness, so much so that you can sleep the whole night through and feel more refreshed in the morning.

[aidenn0]

Aside from urban noise, I don't sleep well if an open window is too close to my bed because I end up with congested sinuses.

[robocat]

> I end up with congested sinuses

Always? I am fine if the air is fresh (e.g. sea breeze onto shore), but tend to get sniffles in city or countryside environments.

[aidenn0]

When it's humid I don't, but dry air invariably does it to me.

[switchbak]

Some new buildings use an HRV system which circulates fresh air in while recovering some of the heat of the exhaust air.

[GloriousKoji]

It's way too loud if I sleep with the windows open.

[ct0]

I'm starting to think that having a better night's rest while sleeping in a tent is not from the ground you sleep on, but the fresh air you've had all night.

[kccqzy]

My best sleep was on a camping trip when we decided that a tent wasn't necessary and we could just sleep outside watching the night sky.

(This is of course highly location dependent. Now that I think about it, I was probably taking a bit more risk at that time than what I tolerate now.)

[Cthulhu_]

It'll depend on the tent, I don't immediately associate tents with good ventilation.

[gumby]

A tent with poor ventilation rapidly becomes soggy.

[prmoustache]

you want to sleep below a tarp then, not in a tent.