Another Netatmo benefit: use aircon but save energy

Shut down arcon at 3 am causes rise in CO2 in closed
bedroom from about 400 ppm atmospheric to almost 800 ppm

Many people leave air conditioning on all night. The thrifty Thai have a better idea.

Here are the data from last night, you can see that if I turn off the aircon at 3 am the temperature (pink) rises, then accelerates at about 7 am (sun on the sliding glass doors, heating the curtains), so I turn on the aircon again for experimental purposes and leave the room. Meanwhile CO2 (green) accumulates when the aircon is shut down, but falls again with aircon on, reaching atmospheric in about an hour.

Yes, a mystery. Isn't the air handler just circulating room air? Why is the CO2 flushed away with the doors and windows closed? I'm thinking that the intake duct is probably pulling some air from some building cavities that contain CO2-free air.

I enjoy this wonderful Netatmo setup and the CO2 data fluctuations lend themselves to all kinds of interesting experiments.

I've talked to various low-budget Thai people who use aircon sparingly as I do. Turn it on at bedtime when the interior is 29 or more, set to 25 C, and then off in the early hours, switching to a fan, which keeps the temp below 29 for the night. This appears to be optimum for energy conservation if you are ok with 29 which works if you use the fan.