Still confused. Are you saying humidifier is futile in Mumbai irrespective of season?
1) Mumbai is very humid. In monsoon i saw 99% RH and generally i see > 70 during night.
2) Humidifier is used to increase humidity. Ideal humidity is 40-60. 60 is comfortable, a user here reported that he had issues below 60. ( he also uses dehumidifier ). What i want is to keep it around 60, esp at nights. High humidity can lead to mold and dust mite issues. Also leads to corrosion in electronics.
3) Only time humidifier would be useful is when humidity is very low ( say less than 40 relative humidity ) which i think only happens in winter during the day. Not sure on this as this is first winter in which i will monitor this via sensor. Also this might be subjective. So far i have not seen < 40. Only > 65 when dehumidifier is not on and it starts increasing at night.
4) ACs bring down humidity when indoor temp is set below outdoor temp. There is dry mode, not sure about that but from what i read, dehumidifier are most effective at bringing down humidity. It also uses much lower power, but it does increase room temp by 1 or 2 degrees. So peak summer, we need acs too.
Get a sensor, then you will know whats exactly happening in your room at different times and different seasons.
So would mostly settle down for one which has a companion app
Just note that the automatic mode in AP ( from what i read ) is generally not good. Sensors are not accurate and AP is not aggressive enough. Ideal average long term PM2.5 is < 5 ( UN recommendation i think ) and generally, auto modes increase fan speed at much higher values.
I just keep it running at speed 3 ( out of 5) in my AP most of the time, noise is low and its pretty effective. Sometimes if my room has too high PM ( windows opened /someone buring /etc), then i ramp it up to 4/5 for 30 mins or so. Even 3 would be effective but would take more time to clear out room.
My unit has some automation and app control too, i just ignore it.