Humidity accuracy problems?

[totoro_ita]

I was looking around the forum and i found a lot of post from different users describing problems with netadmo station humidity measured values.
forum.netatmo.com/viewtopic.php?f=2&t=2005
forum.netatmo.com/viewtopic.php?f=2&t=1995
forum.netatmo.com/viewtopic.php?f=3&t=1559
forum.netatmo.com/viewtopic.php?f=3&t=1031
forum.netatmo.com/viewtopic.php?f=3&t=1509
forum.netatmo.com/viewtopic.php?f=3&t=1743

At this moment the reading are:
* Netatmo: 19.3C / 60%
* Davis weather station: 20.6 / 44%
* electronic T/humidity sensor: 20.7 / 46%
* mercury thermometer: 20.5C
* hair hygrometer: 44%

The major problem seems to be the humidity sensor.
The accuracy of the humidity measure is very important to check the indoor comfort!
And humidity can change really fast when opening windows or turning on/of mechanical ventilation. Why the netadmo is so slow to check the humidity changes?

I think that support should give a clear and reliable answer about the accuracy of the temperature, humidity and CO2 sensor.
It seems that the data in the specification table is not what these users found in their devices.
Can you give us the data specification of the sensors inside netadmo please?

[Theradur]

The temperature measurement seems to be very inaccurate too. It shows more than 1°C lower values compared to your other measurement equipment and relative humidity is temperature dependent (will be a problem if the humidity sensor is not temperature compensated by itself).
I was thinking about buying one Netatmo, but it seems that it only looks good from the outside and the inner values are more than crap. Does someone know which sensors (company and type) were used for measurements?

[wxman2003]

I have had my unit for about 5 days now and indoor humidity is still around 15-20% too high. However, the rest of the readings both indoor and out are accurate. Temperture is generally within 1 degree F of another instrument I have. How old is your other equipment? In general, the longer you have owned the equipment, the more likely it has drifted from orginal calibration. I worked for over 30 years at the National Weather Service, and their more expensive electronic equipment needed to be recalibrated at least once a year due to normal drift from baseline. Not saying your equipment is wrong, but over time they all become less accurate. Oddly enough, if your mercurial thermometer was properly built, it will be the most accurate over the years.

[josr]

Netatmo should come with a product recall because humidity sensor is useless.

Their marketing nightmare so far:

- User complaining on this forum about sensor accuracy
- Negative reviews eg on amazon start to show up
- etc

[Perahim]

I also have humidity sensor problem.
Support only knows to "calibrate" my station, but this not solves the problem.
I loved Netatmo... But less now!

[michalmc]

A communicate with you? Performed the calibration? Me neither silent. How long did you wait for their response? I do not like their behavior.

[michalmc]

Today I made ​​a calibration and it seems that the values ​​are right now. I will inform further.

First measurement 16:43 (August 9, 2013):
IndoorT: 27.2 ° outdoorT: 27.0 ° Weather Station (mechanical): 27.0 ° thermometer: 27.1 °
indoorH: 61% outdoorH: 63% Weather Station (mechanical): 61%

Second measurement 17:32 (August 9, 2013):
IndoorT: 27.2 ° outdoorT: 26.9 ° Weather Station (mechanical): 26.9 ° thermometer: 26.8 °
indoorH: 62% outdoorH: 63% Weather Station (mechanical): 62%

[Roberto72]

let's wait some different condition...

[michalmc]

After calibration, I have the following values:

First measurement 16:43 (August 9, 2013):
IndoorT: 27.2 ° outdoorT: 27.0 ° Weather Station (mechanical): 27.0 ° thermometer: 27.1 °
indoorH: 61% outdoorH: 63% Weather Station (mechanical): 61%

Second measurement 17:32 (August 9, 2013):
IndoorT: 27.2 ° outdoorT: 26.9 ° Weather Station (mechanical): 26.9 ° thermometer: 26.8 °
indoorH: 62% outdoorH: 63% Weather Station (mechanical): 62%


Outdoor measurements on the terrace at a slight rain (placed at 18:05):

First measurement 19:04 (August 9, 2013):
IndoorT: 20.0 ° outdoorT: 20.2 ° Weather Station (mechanical): 19.9 ° thermometer: 20.3 °
indoorH: 87% outdoorH: 85% Weather Station (mechanical): 88%

Second measurement 19:39 (August 9, 2013):
IndoorT: 19.6 ° outdoorT: 19.7 ° Weather Station (mechanical): 19.8 ° thermometer: 19.8 °
indoorH: 87% outdoorH: 85% Weather Station (mechanical): 88%

The response to humidity change is slow. After 1 hour, all the sensors are aligned. But otherwise it looks fine.

[martinstitolarefisso]

Hi Michalmc,
how did you made the calibration? It looks like my sensor need this calibration too.