Humidity+Sensor+is+not+accurate

Problem
Humidity sensor is inaccurate, when compared to other weather stations.

Solution
> > Note that humidity accuracy, like most other measurement parameters, are a percentage of full scale, and not a percentage of point. > > > > > or contact Ambient Weather for out of warranty replacements: [|www.ambientweather.com] > While at the website, enter the part number of the transmitter in the Search by Keyword to locate the product.
 * 1) Place the sensor inside next to the indoor console sensor. Wait about 24 hours for stabilization. The sensors should agree within the accuracy specifications. Most digital capacitive hygrometer sensors are accurate within +/- 5%. Thus, the sensors should agree within 10% when considering full tolerance stack up.
 * 1) [|Sling psychrometers] or [|humidity calibration kits]are very accurate. Perform a formal calibration. The humidity should agree within 5% of the packet rating. You can also make your own calibration kit here: Humidity Calibration Saturated Salt Test
 * 1) Place the sensor in a shaded area on the north side of the structure to avoid direct and radiant heat.
 * 1) Humidity is significantly impacted by external factors like location and water (grass, lakes, rivers, etc). Insure proper installation.
 * 1) If the problem persists, contact the manufacturer if it is in warranty (usually one year): Manufacturer Contact Information
 * 1) If it was purchased from Ambient Weather in the last 30 days, please visit [|Returns & Exchanges].

Frequently Asked Questions
> This is a poor method for comparing your humidity since you are in a different location and the reporting station may update only once per hour. In addition, sensor placement is very important. You will find the humidity on the north side of your house (mostly shade) is much different than the south side of your house (mostly sun). In addition, grass, trees, structures and houses and have a large impact on humidity. The National Weather Service requires very strict guidelines in installing sensors. However, they do not always follow their own guidelines. [|SurfaceStations.org] has done a wonderful job of documenting the poor quality of official NOAA weather stations. > Again, compare to a psychrometer or calibration kit (see above) in a shaded, well controlled area, like the inside of your house. > Digital hygrometers use a humidity sensitive capacitor. The electronics measure this capacitance and it is converted to a humidity. All resistors have small variations which result in variations in humidity. It is impossible to integrate a bi-metal hygrometer (dial hygrometer) into a digital device. > There is a linear relationship between capacitance and humidity within a specified range, and then becomes non-linear at the extremes. Thus, the accuracy can not be guaranteed at extreme conditions. Also, make sure you use lithium batteries in the remote sensor, which operates better during cold weather conditions. > The humidity is inside a housing and the housing has a time constant associated with it. > Humidity is a very difficult parameter to measure below 20%. Expect larger variations in humidity at low humidity levels. Some weather stations limit humidity measurements to 20% because below this level, the accuracy is out of specification. > Yes, humidity sensors are subject to drift over time. The National Weather Service wil calibrate and/or replace the humidity sensor once per year.
 * 1) **My humidity reads different than an official weather station, like National Weather Service, Weather Channel, etc. Why is that?**
 * 1) **Why do digital hygrometers have a margin of error** ( +/- 5%) **? If they are more expensive than a dial hygrometer, shouldn't they be more accurate?**
 * 1) **Can the humidity sensor be calibrated?**Only a few weather stations have calibration capability. They tend to be higher end weather stations with computer connectivity.
 * 2) **At the humidity extremes, my sensor is less accurate. Why is that?**
 * 1) **My humidity is slow to respond. Why is that?**
 * 1) **At low humidity, my sensor is innacurate. Why is that?**
 * 1) **Will my humidity sensor drift over time?**