IKEA's ALPSTUGA humidity update delay – normal behavior?

Hardware
1

Hi everyone,

I’m testing the ALPSTUGA sensor in a bathroom and had some questions about how humidity updates work.

Shower started at 08:45 with a lot of steam.

  • Humidity stayed at ~55% initially
  • Changed to ~85% about 5 minutes later
  • Then reached ~98% around 10 minutes after that

This means the first few minutes of shower activity were not reflected in humidity readings.

I also noticed that in the IKEA home smart view of the sensor, including its history chart, timestamps seem shifted (for example, peak shown at 6:45, 2 hours before actual time).

This made me wonder if I’m misunderstanding how the sensor reports data.

Questions:

  • Does ALPSTUGA only update humidity at fixed intervals?
  • For bathroom automation, would the other IKEA sensor, TIMMERFLOTTE, behave differently?
  • Is it possible to trigger automations based on humidity in the IKEA Home Smart app, or does that require to code something in homeassistant?

Thanks for any insight from people already using it.

2

I’ve tried the Timmerflotte and it works fine when used with something like a derivative sensor to turn on a bathroom fan, but its slower than an Aqara temperature and humidity sensor, even though both do increase their reporting frequency when changes are rapid.

As does the alpstuga, which as you can see from this graph:-

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Was reporting every few seconds (20-30) around 8.50 when the value was changing rapidly.