Topic: Most accrurate indoor humidity sensor?

[Greg_M]

I live in the high desert and the humidity gets very low on occasion, specially indoors.
Just wondering who makes the most accurate humidity sensor (digital or analog) for when it gets in to the teens.

I bought the wife a set of those 5 temp/humidity sensors units so that she can scatter them around the house (she has plants) and I'm not real confident they are telling us the truth.

Suggestions?

[galfert]

Probably not the best...but probably good enough and very flexible and expandable and reasonably priced....

Ecowitt GW1000 as the base console (you see the data live on your mobile). You can also see the data (and graphs) updated every 60 seconds on Ecowitt.net. Online service is free.

Add up to 8 sensors. Have them in every room that you want to monitor and then also add soil moisture sensors to plant pots or garden.

Sensor used is a Sensirion SHT30
humidity range: 10% to 99%
humidity accuracy is +-5%
humidity resolution: 1%

You can buy it directly from Ecowitt or from Amazon.

[miraculon]

I bought one of these from Amazon. The photos show a "Professional Accuracy" insert with a SHT3x device. The claimed range is 1% to 99% RH.



It seems to work well. We don't have desert humidity here in Michigan by any means, so I can't confirm operation at low level RH.

Greg H.

[DaleReid]

A couple years ago I bought a Sensirion sht31 evaluation 'kit' which is a two line lcd display, a coin battery, and a sensor all on an open pc board.  I think it is as accurate as the sensor shows.  The readout is impressive to the hundredths of a decimal point, but doubt if it can really resolve anything that close.  Not elegant, but looks sort of cool and seems to work pretty well.

[havtrail]

I bought one of these from Amazon. The photos show a "Professional Accuracy" insert with a SHT3x device. The claimed range is 1% to 99% RH.



It seems to work well. We don't have desert humidity here in Michigan by any means, so I can't confirm operation at low level RH.

Greg H.

This review is right on the Amazon listing, indicating a problem with RH under 10%:

Good measure of humidity, until RH is less than 10%
February 27, 2019
Verified Purchase
This device did a great job monitoring humidity and temperature, until the cold and dry New England winter. At our office, they do not try to control humidity, so it can go really low. Several times I have watched the humidity reading drop down towards 10.0% RH, and as soon as it reaches 10.0% it jumps to 99.8% RH. This has to be a software/ firmware bug. I have never seen the meter display less than 10.0% RH. Changing to fresh batteries and cleaning the contacts does not help. At first I thought that changing batteries fixed the issue, but it was just the moisture from my hands temporarily bumping up the RH of the unit.
I would definitely give this device a 4 star rating, maybe even a 5 star, if it were not for this "feature."

Rich K.

[ValentineWeather]

Problem with Amazon they lump all reviews together even after new models come out. You can't trust all the reviews for sure. The SHT31 version just came out last year and has no problem below 10% humidity.
Look for this indoor sensor nothing available is any more accurate and for $15 its a steal.

Pro Accuracy Indoor Temperature and Humidity Monitor
 [ You are not allowed to view attachments ]

[Greg_M]

I got the "AcuRite 01080M Pro Accuracy Temperature and Humidity Gauge with Alarms, Black " and am quite impressed with it.
It's fast in response and seems to be accurate. The price is a bonus.
Thanks for recommending this.

[txbayou]

This article describes a few more hygrometers: https://www.weatherstationadvisor.com/best-hygrometer-reviews/, but the Acurite model described doesn't look to be one of the newest M suffix models.

I've always been intrigued (haven't bought one yet) by the graphics of the Ambient WS-3000, even if that part of the display is tiny. But it's not for humidity below 10%:https://www.ambientweather.com/amws3000x5.html#caption

[galfert]

I've always been intrigued (haven't bought one yet) by the graphics of the Ambient WS-3000, even if that part of the display is tiny. But it's not for humidity below 10%:https://www.ambientweather.com/amws3000x5.html#caption

That is because the Ambient stuff uses the Sensirion SHT30. I wonder if anyone attempted SMD soldering or PCB hacking (tapping into board traces) if they could replace it with an SHT31 (or SHT35 or SHT85)....or would it be limited by firmware to still only show min 10% RH.

[wase4711]

lets hope the indoor humidity doesnt go below 10%, ever, that would be terrible!
yesterday here outside Phoenix, the outside humidity was 2% for awhile, according to my VP2..with a temp of 99, and 2% RH, the dewpoint was -7, something I hadnt seen before..

[idahowx]

A couple years ago I bought a Sensirion sht31 evaluation 'kit' which is a two line lcd display, a coin battery, and a sensor all on an open pc board.  I think it is as accurate as the sensor shows.  The readout is impressive to the hundredths of a decimal point, but doubt if it can really resolve anything that close.  Not elegant, but looks sort of cool and seems to work pretty well.

I have the same kit and checked the accuracy.  It is fairly accurate.  The spec sheet lists a resolution of .01C which is possible given the -40C to 125C range with 16 bit measurement data.  They claim repeatability can be as good as .04C typical and it did appear that the stability was under a tenth in the chamber.

               Eval_Brd
Temp         SHT31
-10C         -9.93C
 30C         30.00C
 50C         49.87C

Humidity   
N2 purge      0.0%
NaCl sol.     75.26% @18.31C

Temp control: Calibrated liquid fluorinert chamber (+/- 0.2C)
Humidity: 100% dry Nitrogen & NaCl saturated solution
 
NaCl saturated solution RH (NBS publication 1976)
75.61%+/-0.18% @15C
75.47%+/-0.14% @20C

https://www.wxforum.net/index.php?topic=36006.0

[CW2274]

2% RH, the dewpoint was -7, something I hadnt seen before..

Told ya the VP2 would show you things up there you hadn't seen before with your old PWS.

[wase4711]

you were right, man, this thing blows away most other stations...glad you talked me into it!