Why are my Conserv sensor readings slightly different from my other devices?

You may have some other devices, like HOBOs or PEM2s, that are also monitoring your collection environment, and they might show different readings.

If you've noticed temperature or relative humidity readings from your other devices reading differently from your Conserv sensors, there are a few things to consider.


1. How old are your non-Conserv devices? 

Over time, devices will lose some of their accuracy.  This is known as "drift".  If you have devices that are more than a few years old and haven't been updated or calibrated, this might be the reason for the difference in readings. We guarantee our sensors for three years, and if we see their accuracy begin to slide we'll send you new ones, on us.

2. When were your non-Conserv devices last calibrated?

All devices need regular calibration to keep their reading accuracy on point. When you receive your Conserv sensors, you can trust that they've been calibrated and tested right before they're shipped to you. Over time, recalibration is necessary for any device, even Conserv sensors. This is why we regularly monitor their accuracy for you, and will send you newly calibrated devices as soon as we notice a difference, or when they reach a lifespan that indicates recalibration is required. If you're not sure when your non-Conserv devices were last calibrated, you might want to consider sending them off for calibration and testing.

3. What is the accuracy range/standard deviation of your non-Conserv device?

Every device will have an accuracy range that is specified by the manufacturer. This range varies from company to company based on a multitude of factors, as it does for the Conserv sensors. That being said, our device may show a different reading from a different company's device because those accuracy ranges are different, sometimes they can even deviate in different directions! It's just always a good idea to know the ranges of all your devices. Our accuracy ranges can be viewed on our spec sheet here: Conserv Sensor, Technical Specifications 

4. How are my different devices measuring the data?

In general, temperature readings are very accurate across manufacturers.  Deviations are much more common in relative humidity readings.  Digital sensors for relative humidity rely on electrical characteristics of the sensor material, such as capacitive or resistive elements.  Two sensors that use different measurement technologies may also yield slightly different results.

If your differences are specifically related to relative humidity, please also read this other article that goes a bit more in-depth into variations in RH readings.

C2C Care Webinar

In 2024, our VP of Customer Experience, preventive conservator Melissa King, co-hosted a webinar with facilities expert Chris Cameron. We strongly recommend watching the section that starts around minute 25:45 where Melissa goes into detail on how to compare sensors.

Can you check your device accuracy in house?

Yes! You can try using saturated salt solutions, which create very specific relative humidity conditions in a small enclosure to check what your different devices are reading versus the known RH you have created. Check out these instructions by AIC.

We are committed to bringing you accurate, real-time data for your collection. If you notice a large discrepancy between your Conserv sensors and other devices that cannot be accounted for with the explanations above, please send us a support ticket