When you change the batteries of your Wave Radon, Wave Plus or Wave Mini, it can take up to 1 hour for the new battery level to be reflected in the app.
This happens because the new battery level information is only sent to the cloud once an hour. When you change the batteries, the monitor will start working straight away, but the battery indicator in the app and dashboard just takes a little longer to update. If you take out the batteries and reinsert them, this will also cause the VOC, CO2 and radon sensors to reboot, meaning they have to recalibrate again. You may notice some fluctuations in the readings in the following few days until the sensors readjust.
This does not apply to the Wave Radon 1st generation, which does not display battery levels in the app.