Reliable method in measuring relative humidity 1

[agus72indo]

Dear all,
Anybody knows the most reliable method (sensor or any othe means) for measuring relative humidity or water activity. I have used some methods (sensors) but they deviate quite alot from the actual values. Thanks for your attention.

Best regards
Agus S.

 

[xnuke]

How do you know the actual values? What sensor is providing the "actual" reading? Most RH sensors have an accuracy of 1-2% these days, at least for those I've encountered in HVAC applications. xnuke

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[nbucska]

dewpoint? <nbucska@pcperipherals.com>

 

[budliteyear]

Not sure what your application is, but one of the simplest and most reliable methods to measure RH is to measure the dew point via a chilled mirror chamber or analyzer, then convert back to RH. Unfortunately most of the cheap RH measuring instruments are just that! If you elaborate more on your application possibly myself or someone else can offer some suggestions.

 

[nbucska]

You can use a mirror cooled with a Peltier cell.
Measure its temp. at dewpoint and ambient and calculate
.

<nbucska@pcperipherals.com>