Relative Humidity Sensor Buying Guide

(Also known as Moisture Meters or Hygrometers.)

"14 Factors to Consider when Buying a Relative Humidity Sensor" Keeping Relative Humidity below 55% is the best way to control indoor molds and dust mites

1. Digital vs. Analog

Digital humidity sensors can store maximum and minimum relative humidity information, while analog humidity sensors cannot. In addition, digital humidity sensors tend to be much more accurate.

800 Series Humidity Sensors: Digital

800 Series Humidity Sensors

2. Records Minimum & Maximum Levels

This allows you to see the range of high and low readings of humidity and temperature since the last time you hit the reset button. As a result, you can gain a better understanding of the typical humidity and temperature levels over a specified time period.

800 Series Humidity Sensor Min/Max Settings: Records minimum & maximum readings for specified time period

3. Display

Out of convenience, it is preferable if you can read the numerals on your humidity gauges display from across the room (or at least halfway across the room). With some humidity sensors, you need to be right up next to them in order to read the display.

Model 811 Display: Readable from up to 45 feet away.

4. Temperature

Temperature is an important part of controlling relative humidity. Simultaneous display of temperature and relative humidity will help you to track your efforts. Moisture meters that also measure temperature are often referred to as thermo hygrometers.

800 Series Humidity Sensors: Celsius and Fahrenheit temperature displayed

5. Outdoor Sensor

As an added bonus, some humidity sensors have an external sensor attached by a cord. This external sensor can be mounted outside, so you can also see the temperature outdoors from your humidity sensor display.

800 Series Outdoor Sensor: "CE" and "E" models include external sensor and sensor holder for mounting outside

6. Celsius or Fahrenheit Readings

Your humidity gauge should offer both Celsius or Fahrenheit readouts to avoid conversion errors.

800 Series Humidity Sensor Temperature Display: Celsius or Fahrenheit selectable

7. Clock / Alarm

Some humidity sensors are designed to show the time in addition to the relative humidity level and temperature. These multi-functional units may also include an alarm.

800 Series Clock/Alarm: "CE" and "C" models include clock with alarm

8. Battery Included

Digital humidity sensors will require a battery in order to operate. If the battery is not included, then you will have to buy it separately.

800 Series Battery: 1 x "AAA" battery (battery included)

9. Easy to Use

Some moisture meters require calibration. However, most homeowners and building maintenance managers prefer something that can run practically right out of the box.

800 Series Ease of Use: No calibration or set up required

10. Wall Mountable or Stand for Flat Surfaces

Some humidity sensors can only be mounted on the wall, and some can only be placed on a flat surface. For the sake of versatility, it is much better to have a moisture meter that can be both mounted on the wall, and placed on a flat surface.

800 Series Placement: Mounting keyhole (on back) for wall mount, and foldaway stand for placement on flat surfaces

11. No Maintenance or Calibration Required

Hygrometers that require maintenance or calibration may be to technical for a homeowner’s or building manager's needs. Moisture meters that require calibration are geared more towards the industrial sector. Plus, calibration kits are typically very expensive.

800 Series Maintenance & Calibration: No maintenance or calibration required

12. Accuracy & Range

Traditional humidistats were only accurate within a 20% RH (relative humidity) margin. Most humidity sensors today are accurate within a 5-10% margin, which will give you a very good idea of what the humidity level is in your home or building. Some of the more expensive, industrial models are accurate within 2-5%. 

A humidity sensor should be able to measure relative humidity between at least 25% and 80%, since these represent extremely low and high indoor humidity levels). Your hygrometer should also offer a significant range for measuring temperature as well.

800 Series Humidity- and Temperature-Measurement Ranges: 20% to 99% (Relative Humidity); -58^oF to 158^oF (Outdoor); 32^oF to 122^oF (Indoor)

800 Series Accuracy: +/- 3% RH; +/- 2^oF (1^oC)

13. Price

To fulfill the humidity monitoring needs for homes and buildings, a $50-or-less model will be sufficient. 

800 Series Pricing: $18.99 to $29.99 (free shipping)

14. Guarantee / Warranty

Just in case you end up with a unit that does not work properly, you should make sure that you only buy humidity gauges with a money-back guarantee. Also, a warranty will ensure that you get your money's worth, although humidity sensors are generally a problem-free product.

800 Series Guarantee & Warranty Policies: 90-day money-back guarantee; 1-year warranty

800 Series Humidity Sensors