4 x Air Gradient One's Temperature Difference Question

[Sunny-TP]

Hi everyone,

I’m new to the forum and have a question I couldn’t find an answer to in my search, so I thought I’d ask here.

I have six Air Gradient One indoor units—two of which I built from kits and placed in separate office rooms. I was happy with their performance, so I purchased four more: one pre-made unit and three additional kits that I assembled myself.

To test the consistency, I placed all four new units side by side for a day and noticed a noticeable difference in temperature readings between them. The largest discrepancy is 0.7°C, with the prebuilt unit showing the lowest reading, while the three kit-built units display higher temperatures.

I didn’t expect perfect uniformity, but is this range of variation (up to 0.7°C, sometimes higher) normal, especially between pre-built and kit versions? I’d appreciate any insights or similar experiences.

Thanks!

[MallocArray]

Are they all standing up the same way and none are laying on their backs?

[Sunny-TP]

Yes, all the units are standing upright next to each other. I’ve attached another screenshot showing the temperature differences observed overnight. The largest gap appears to be about 0.84°C. I’m assuming the pre-built unit is likely the most accurate. If that’s the case, how can I calibrate the other units to align their readings more closely with the pre-built one?

For context, the temperature differences remain consistent whether I view them in Home Assistant or on the AirGradient dashboard.

[MallocArray]

You may also double check where you put the temperature sensor vs the VOC (SGP41) sensor. The Temperature sensor should be at the bottom left of the board when it is standing up. This is so it pulls in fresh outside air as it convects up. If you have it located at the top right of the board, then it is getting warmed by the other chips and sensors inside of the case, resulting in higher temperatures.

The AirGradient ONE Air Quality Sensor (Presoldered-Version, PCB Version 9)

[Sunny-TP]

I wanted to try a few things before replying. After double-checking the sensor locations on all devices, I confirmed that they were positioned correctly. Just to rule out any environmental factors, I relocated the devices to a completely different spot. They’ve been running in the new location for a few days now, and the temperature readings have been stable, staying within a 0.2°C range.

I’m pretty happy with the results now. Thanks!