Room temperature and humidity at ceiling and floor level


this is more a physics than a tech question :smiley: In some rooms I have now 2 sensors for temperature/humidity. At switch height (~1m from floor) an Aqara ‎WSDCGQ11LM and the same capability with the Samsung Windfree AC (at 2m from floor).

Observing both values, I see quite some difference.

Humidity at the AC level is roughly 10% less, and temperature roughly 1C more.

Are those amount of differences in a room possible or are the sensors fooling me.

Curious if anybody has an explanation :slight_smile:

If I were to venture a guess, I would say it’s a little of both - sensor inaccuracy and physics. Certainly the temperature should be higher towards the ceiling since heat rises, and humidity should be lower at the floor since water is heavier than air but having two sensors from two manufacturers could, and likely would, render different values anyway.

I’ve seen this happen as well and there are certainly other factors to consider, such as if a sensor is in direct sun versus shade, or if a carpet is retaining water more than a plaster ceiling and thus reporting higher humidity as a result.

For temperature, when I’m questioning my devices I use a high quality meat thermometer to measure the temperature and see how close my sensors are, that’s about as far interested as I am in finding the answer because I save my complex physics calculations for other things like determining how much water evaporates naturally versus when my humidifier turns it into a mist so I can figure out the relative water level still left in the tank - and that gets exhausting enough :joy:

Hahaa - thank you for your thoughts. Especially the humidity difference is a bit odd. I ll grab a sensor I trust to figure out the truth now

You’re measuring RELATIVE humidity, which is directly affected by dry bulb temperature. If you take the same air and heat it, the relative humidity will go down and vice-versa. What you’re seeing matches up with that.


Take your Aqara sensor and temporarily mount it beside your Samsung sensor. Then compare the differences.

As noted, 2 sensors from 2 manufacturers certainly have the potential to be off from each other. And both sensors have the possibility to not be exact. But I believe you can set an offset in the Aqara device, so by putting it next to the Samsung sensor, you should at least be able to dial them in so they read the same and then move it back to where you had it.

But generally speaking, yes you should see a difference the higher you go so it may be normal.

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