Factory Recalibration / Certification

The Kestrel should be recalibrated if the Relative Humidity (RH) sensor has shown drift in its RH measurement.  The Kestrel RH sensor is specified to develop less than 2% drift over 24 months.  If you would like this service performed, please contact us info@kestrelmeters.com. There is a $65 charge to calibrate relative humidity and the related measurements.  Recalibration is available with and without certification of NIST traceability and calibration stickers.  We can recalibrate and certify any of the values measured by your Kestrel meter, including: wind speed / air flow; temperature; barometric pressure and humidity.  

Factory calibration for the Kestrels is done at 32.8% and 75.3%.

Kestrel 5000 Series Calibration:

With the new 5000 series, the need to calibrate the RH is highly unlikely.
NK will stand by the RH for 5 years, and will adjust it within that 5 years if needed at no charge.
NK will repair, recalibrate or replace any defective product within the warranty period. "Defective" includes measurements outside of our accuracy spec plus stated drift.

After the 5 year warranty period, it may need to be done, but we'll know then if it needs to be sent in or not. Currently, the goal is to have the technology to do it remotely. Please note, the Calibration Kit cannot be used on 5000+ series meters. 


For RH Field Calibration, purchase this Calibration Kit, for basically unlimited calibrations with only needing replacement salts. Please note, this kit cannot be used with the 5000+ series meters. 

For Wind Calibration, all you need is a new Impeller.  Each impeller is tested in the US factory wind tunnel and get thrown off when dropped, hit by debris, or periods of exposure to dust (in mines).

How often should you calibrate your meter?

Largely it’s dependent on whether it’s industrial use or consumer use. Acousticians recalibrate annually, firefighters annually or semi-annually, and general consumers might recalibrate them every 4 or 5 years or so. The official stance is that a calibration is recommended every 24 months due to the possibility of up to 2% calibration drift over 24 months.

If you're Kestrel Meter is flashing 'E1', this means the humidity sensor needs to be re-calibrated. If the unit is less 30 days old (from the date of purchase) you may send it back to NK for re-calibration under warranty. If it has been more than 30 days from purchase, it can be returned to NK for a humidity calibration for $65 (free return shipping).  OR - you can buy this calibration kit and do it yourself. Please note, the calibration kit cannot be used for 5000+ series meters. 

NIST Calibration Instructions

NIST on an Existing Meter:  If you need your meter calibrated and tested and NIST certified, you'll want to visit this NIST Existing Meter page.  You will find instructions on how to get this done.

NIST on a New Meter: You can purchase your meter on this site, and then add the NIST certification testing from this NIST New Meter page.


Kestrel Calibration