Although a bit above $200, but I own an Aranet4 CO2 monitor (it also measures hu...

		rpozarickij on Dec 10, 2023 \| parent \| context \| favorite \| on: Ask HN: What sub $200 product improved your 2023 Although a bit above $200, but I own an Aranet4 CO2 monitor (it also measures humidity, air pressure, and temperature). It has a great app that allows you to see historical data too. I've been using it for a while already and I'm really happy with it.

It's on sale right now at $149, I just bought it thanks to your comment!