Why DHT22 Is Better Than DHT11?

DHT temperature and humidity sensors, are very basic and slow, but are great for hobbyists who want to do some basic data logging. Each DHT is made of two parts: Capacitive Humidity Sensor and Thermistor. There is also a very basic chip inside that does some analog to digital conversion and spits out a digital signal containing temperature and humidity readings. This digital signal can be read by any microcontroller.

Below is a table comparing the specs of DHT11 and DHT22. When a sensor lead in a row, it will win one point, at the end we’ll see the scores for each one.

DHT11

DHT22

Winner

Price

Ultra low cost

Low Cost

DHT11 – Points: 1

Voltage

3 to 5V power and I/O

3 to 5V power and I/O

Maximum Current Use

2.5mA max current use during conversion (while requesting data)

2.5mA max current use during conversion (while requesting data)

Humidity Reading Range

20 to 80% with 5% accuracy

0 to 100% with 2 to 5% accuracy

DHT22 – Points: 2

Temperature Reading Range

0 to 50°C with ± 2°C accuracy

-40 to 80°C with ± 0.5°C accuracy

DHT22 – Points: 4

Sampling Rate

1Hz (Once every second)

0.5Hz (Once every two seconds)

DHT11 – Points: 2

Body Size

15.5x12x5.5 mm

15.1x25x7.7 mm

DHT11 – Points: 3

Pinout

4 pins with 0.1” spacing

4 pins with 0.1” spacing

So DHT22 wins having 1 point over DHT11, but what matters is the range that you want to read, the frequency of reading can also be important for some application.

DHT22 is better then DHT11, but it isn’t a waterproof sensor, check DS18B20 for waterproof temperature sensor.