There is a maximum room size that your Philips Humidifier or 2-in-1 Purifier & Humidifier can humidify. If you exceed the recommended room size
When windows or doors are open, the humidity from your Philips Humidifier will not remain in the room. Please close the doors and windows.
for your specific humidifier model, the indication on your appliance or hygrometer will not change since your appliance will not be able to provide the expected results.