Kestrel versus the Competition
At Nielsen-Kellerman, weather is serious business!
We’ve
been researching, designing, manufacturing and distributing our
Kestrel Meters for 10 years. NK’s founders and lead engineers,
Richard Kellerman and Paul Nielsen, are determined to make the
most accurate and reliable hand-held weather devices available.
They have developed four patented measurement technologies for
the Kestrel family and continue to research ways to improve the
Kestrel line and create new products to meet their customers’ needs.
While it may not be obvious when you look at
a Kestrel side-by-side with a competitor’s weather meter,
there are very important differences that make Kestrel the best
choice for almost every application.
Certified and Guaranteed Accuracy
Every single Kestrel manufactured at NK is calibrated for every
single value, either directly against NIST-traceable standards
or against an intermediary standard calibrated daily. (The National
Institute of Standards and Technologies is the federal technology
agency that works with industry to develop and apply technology,
measurements, and standards.) Every unit is shipped with a FREE
Certificate of Conformity that states what calibrations were performed,
and the certified performance specifications. What does that mean
for the customer? They can be absolutely sure that their weather
readings are accurate to the stated specifications. Some competing
weather instruments claim the same specifications as Kestrel, but
only Kestrel certifies their accuracy. For an additional
charge, NK can even provide a NIST-traceable Certificate of Calibration
that specifies exactly which values were measured in each multi-point
calibration, and details the calibrated standard used for testing. Our
30-day satisfaction guarantee covers accuracy concerns as well.
If a customer questions their unit’s accuracy after purchase,
they can contact us and we’ll double-check every calibration
to verify the unit meets specifications.
US Manufacturing
The entire Kestrel line is designed and built
in the USA – no
other handheld weather meter is. Some electronic components have
to be sourced overseas these days, but we buy American wherever
we can. We believe US manufacture is the only way we can ensure
that every Kestrel will do its job right, and we also believe it’s
important to do our part to keep manufacturing alive and well in
the US.
Money-Back Guarantee
We have a 30-day satisfaction guarantee, and a 5-year warranty.
Our track record speaks for itself - the return rate for the entire
Kestrel line for any reason is 0.002%. Even after the regular warranty
expires, we cover every Kestrel FOR LIFE with our Customer Care
Warranty Program, which allows users to trade in a used or damaged
Kestrel for a new one at about half price. And, if you ever have
a problem or question about their Kestrel, you can come straight
to us. From our Customer Service Representatives to the President
of the company, we all answer the phone and know these products
inside and out. If you have a problem, we'll fix it.
Patented Removable Impeller
The Kestrel impeller measures 1 inch across
and turns on a Swiss precision pivot mounted on sapphire bearings.
Its large size ensures accurate readings even if pointed off-angle
from the wind, and its very low start-up speed allows measurement
of the lightest puffs of wind. Units with smaller impellers simply
can’t
match the Kestrel’s performance at low wind speeds. If damaged,
a new calibrated impeller can be purchased for $19 and popped in
without tools, restoring like-new performance. We designed and
patented this removable impeller technology, and it keeps Kestrel
Meters accurately measuring the wind speed for years.
Patented Dual Temperature Sensor RH Measurement
Relative humidity is tricky to measure – particularly in
a sealed product. But, with wildland firefighters among our leading
customers, we know it is essential that we get it right. Firefighters
typically work in extreme conditions with very low humidity levels,
and their lives literally depend on accurate readings. Accurate
temperature measurement is critical to calculating relative humidity.
That’s why NK developed the patented Kestrel dual temperature
sensor configuration. It is not necessary to wait the 20 to 40
minutes that would normally be required for the unit temperature
to equilibrate to the air temperature after a temperature shift.
So long as airflow over the temperature sensor is maintained, either
by holding it into a breeze or waiving it in the air, the external
temperature sensor will provide instant and accurate readings of
the outside air temperature, while the second sensor in the humidity
chamber provides the critical information about the internal unit
temperature (even if different). The Kestrel then performs
the calculations necessary to yield relative humidity accuracy
of +/- 3%RH from 5 to 95% (both impressive statistics usually only
found in units costing hundreds of dollars more). The humidity
sensor in the Kestrel has been selected for long-term stability
and reliable performance even at very low and very high humidity
conditions. Every Kestrel is calibrated against NIST-traceable
standards, and can be recalibrated in the field with the Kestrel
RH kit.
Patented Temperature Measurement
Unlike most watches and other products with
a temperature measurement, the Kestrel sensor is outside the
case to ensure it measures the air, not your hand or pocket.
The "curls" serve to further
isolate the temperature sensor from the effects of the case temperature.
Again, simply wave the Kestrel back and forth a few times and you’ll
have accurate air temperature readings in seconds. And, since the
Kestrel is completely waterproof, you can actually take water temperature
and snow temperature readings – simply submerge the sensor
in the water or snow. Just ask the US Biathlon team – they
used Kestrel 4000’s in the 2006 Winter Olympics to measure
air and snow temperature to determine the appropriate wax to use
on their skis.
Pressure Corrected Wet Bulb Temperature
Meters that provide wet bulb temperature readings
without a pressure sensor assume standard atmospheric conditions,
leading to highly inaccurate readings on low-pressure days, at
high altitudes, or in any other “non-standard” situation.
Kestrel meters only offer wet bulb temperature readings on our
pressure-sensor equipped units, ensuring accuracy in all conditions.
Reliable Delta T
Delta T is a reading commonly used in dry climates
to provide a quick guide to acceptable spraying conditions. It’s the
spread between the wet bulb temperature and the dry bulb temperature.
For example, it is not recommended to apply pesticides when Delta
T is above10 – a range of 2 to 8 is ideal. With the new Kestrel
3500 Delta T, the calculation is done for you, accurately and simply.
Because the wet/dry bulb spread can be quite small, even a small
error in either temperature reading will generate a large percentage
of error in Delta T. The Kestrel 3500 Delta T does correct for
pressure, ensuring that Delta T is measured accurately. NK currently
sells our Delta T model primarily in Australia, but if you are
interested in it, please contact us.
Leak and Drop Testing
NK specifies IP-67 sealing for every Kestrel.
This means that a Kestrel is totally protected from dust and
can be submerged in water to 1 m (3ft) for up to 30 minutes without
any leakage. To ensure that each Kestrel meets this standard,
we subject each one to a vacuum leak test after final assembly.
We’ve heard of
one Kestrel product tester who sank it in a lake for a full day
of fishing, then pulled it out and put it back to work (that’s
dedication!), and the appearance of Kestrel meters employed in
underground coal mines is testimony to their dust-resistance. We
have also drop-tested the Kestrel lineup to MIL-STD-810F.
Field and Factory Recalibration
Not only is every Kestrel guaranteed accurate
when it leaves the factory, but accuracy can be ensured by field
and factory recalibration for years of reliable performance.
Many highly technical applications require that measurement tools
be recalibrated on a regular schedule. Relative humidity, wind,
and barometric pressure measurements on each Kestrel can be calibrated
in the field, no matter how old the Kestrel. To restore the wind
speed calibration, the user need simply replace the impeller.
To calibrate the relative humidity, the customer can employ the
Kestrel Field Calibration Kit send their unit back to us for
factory recalibration. Recalibration of the barometric pressure
is also possible so long as the user has a source of an accurate
pressure reading. (Instructions are posted on our web site or
the unit can be returned for factory calibration.) The only sensor
that cannot be recalibrated is the temperature sensor, but in
our 10 years of manufacturing Kestrels, we’ve never come
across one that needed to be recalibrated.
Product Tune-Ups and Certification
If you would like to have your Kestrel checked for accuracy and restored
to like-new performance, NK offers a Tune-up service that includes
a new impeller, new batteries and full recalibration for a fraction
of the original purchase cost. We also offer NIST-traceable Certificates
of Calibration for industries that require it.