# Accuracy of SNZB-02D vs SNZB-02

**URL:** https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107
**Category:** Free discussion
**Created:** [March 31, 2024, 8:37am UTC](https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107 "2024-03-31T08:37:37Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![andy.wolf](https://avatars.discourse-cdn.com/v4/letter/a/7ab992/32.png) [@andy.wolf](https://forum.ewelink.cc/u/andy.wolf)
#### Post date: [March 31, 2024, 8:37am UTC](https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107/1 "2024-03-31T08:37:37Z")

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Hi all

I have been using a number of SNZB-02 for a while around the house.

I have now picked up a SNZB-02D to replace one of the SNZB-02.

However, after placing the new SNZB-02D in the same location as a SNZB-02 previously was, I noticed that the Humidity reading on the SNZB-02D was significantly lower. So I placed the SNZB-02 directly next to it to compare measurements between the two devices.

 ![IMG_8125](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/f/f16376593a49ce2a44b34b2e41b0ffaa4aeb12f9.jpeg)

The Temperature measurement between the devices is within normal margins - however there is a significantly difference in the Humidity measurement. The Humidity displayed by the SNZB-02D (top) is around 10% lower than that of the SNZB-02 (bottom). This difference is persistent across several hours.

 ![IMG_8124](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/d/deda865f6ffe7a342a98145beb237c3496521d0b.jpeg)

 ![IMG_8126](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/0/0efb3c0476b7b883847946bfa7200da5db926d40.jpeg)

 ![IMG_8127](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/b/bcb3768f5c7705abf23c0b1edc27b10113790432.jpeg)

Which one am I supposed to believe?

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### Author: ![jam3](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.ewelink.cc/jam3/32/7918_2.png) [@jam3](https://forum.ewelink.cc/u/jam3)
#### Post date: [March 31, 2024, 3:03pm UTC](https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107/2 "2024-03-31T15:03:47Z")

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None. Both are for home use and are not certified measuring instruments.

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### Author: ![andy.wolf](https://avatars.discourse-cdn.com/v4/letter/a/7ab992/32.png) [@andy.wolf](https://forum.ewelink.cc/u/andy.wolf)
#### Post date: [April 1, 2024, 9:49am UTC](https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107/3 "2024-04-01T09:49:24Z")

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@jam3 : Thanks - am aware of that. However, I would still expect a certain degree of accuracy. Otherwise what is the point of such a sensor?

After some googling I found lots of reports that the original SNZB-02 is over-reporting humidity by about 10%.

I placed 2x SNZB-02 and the new SNZB-02Dd next to my Ecowitt sensor to have another reference point in the mix. Here the results:

| Device | Temperature | Humidity | |
| --- | --- | --- | --- |
| Ecowitt | 25.8 ⁰C | 52% | |
| SNZB-02D | 25.9 ⁰C | 50% | |
| SNZB-02 (I) | 25.9 ⁰C | 61% | |
| SNZB-02 (II) | 25.9 ⁰C | 59% | |

The SNZB-02D is within acceptable margins for Humidity compared to the Ecowitt - but both SNZB-02 are way out.

So the original SNZB-02 do not provide reliable Humidity readings.

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### Author: ![jam3](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.ewelink.cc/jam3/32/7918_2.png) [@jam3](https://forum.ewelink.cc/u/jam3)
#### Post date: [April 1, 2024, 2:27pm UTC](https://forum.ewelink.cc/t/accuracy-of-snzb-02d-vs-snzb-02/30107/4 "2024-04-01T14:27:18Z")

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Everything you wrote about was predictable. For what purpose did you actually start the topic?