Ask HN: Best way to remove CO2 in a bedroom?

I know that CO2 sequestration/capture is imperfect and expensive; however, I was wondering if there is a doable way to remove CO2 in a bedroom at night, to improve air quality why we sleep?

Plant

Ventilation is usually the best way. Even when there is a temperature differential between the outside and inside, it's more economical to heat up / cool down in the new air than trying to scrub CO2 [1]

If you have an air quality concern, you can start by installing an indoor air quality monitor with a CO2 sensor.

[1] https://en.wikipedia.org/wiki/Carbon_dioxide_scrubber

Not being snarky, but a window is one of the best options. Air conditioners can often be your worst option, as the air is recirculated more aggressively. We use a window fan that has multiple settings: circulate, ingress, egress. I find that no matter what setting you use, air is recirculated significantly well. On hot days, the fan is set on egress. This seems to do a really great job of removing excess CO2 while not bringing that much hot air into the house. We have a window fan running in the kitchen for the bulk of the year. We also find that simply cracking the windows in the winter makes a large and measurable difference in CO2, but not with heat.

Not sure that’s effective enough to make a practical difference.