DHT11 vs DHT22 Comparison

DHT11 vs DHT22: Which Temperature Sensor Should You Buy?

The DHT11 and DHT22 use the same single-wire protocol, work with the same Arduino/ESP32 libraries, and look nearly identical. But they have meaningfully different accuracy and operating ranges. Here is a direct comparison to help you decide.

Specs Side by Side

Spec	DHT11	DHT22 (AM2302)
Temperature range	0 to +50°C	-40 to +80°C
Temperature accuracy	±2°C	±0.5°C
Humidity range	20–90% RH	0–100% RH
Humidity accuracy	±5% RH	±2–5% RH
Sampling rate	1 Hz (1 reading/sec)	0.5 Hz (1 reading/2 sec)
Supply voltage	3–5.5V	3–5.5V
Current (measuring)	~0.5 mA	~1.5 mA
Price at Circuitkar	₹50–80	₹130–180

The Critical Differences

Temperature accuracy: DHT11's ±2°C error matters in practice. At 28°C ambient, a DHT11 might read anywhere from 26°C to 30°C. For room temperature display where ±2°C is visually acceptable, it works. For HVAC control, pharmaceutical monitoring, or any application where accuracy matters, ±0.5°C from the DHT22 is the right choice.

Negative temperatures: DHT11 simply cannot measure below 0°C. If your project will be in a cold storage room, outdoor in winter, or any environment that drops below freezing, DHT11 is unusable. DHT22 works down to -40°C.

Humidity below 20% RH: DHT11 does not measure below 20% RH. In dry climates or air-conditioned rooms in winter that drop below 20% RH, DHT11 gives no reading. DHT22 measures from 0%.

Sampling rate: DHT11 reads once per second; DHT22 requires 2 seconds between readings. This rarely matters for monitoring applications, but if you are calling the read function in a fast loop without the minimum interval, you will get read errors. Use the DHTesp library which handles timing internally.

Same Interface, Same Library

Electrically identical: VCC (3.3V or 5V), DATA, GND. The DATA pin needs a 10 kΩ pull-up resistor to VCC. Same pinout, same library (DHTesp or DHT by Adafruit).

In code: just change dht.setup(PIN, DHTesp::DHT11) to dht.setup(PIN, DHTesp::DHT22). No other code changes needed.

Which to Buy: Decision Guide

• Classroom demo, LED display, or non-critical monitoring: DHT11 is fine. Save ₹80.
• Deployed home/office sensor, weather station: DHT22. The accuracy difference justifies the cost.
• Outdoor installation, cold storage, HVAC control: DHT22 always. Consider BME280 (I2C, adds pressure, smaller package) for ₹180–250 as an upgrade.
• Final year project that will be evaluated: DHT22 makes your project look more professional. Panels notice sensor specs.

Alternative: BME280

If you need temperature, humidity, and barometric pressure in one module, the BME280 (₹180–250) is worth considering. I2C interface, smaller form factor, ±0.5°C accuracy on temperature, ±3% RH on humidity. Excellent for weather stations where altitude/pressure data adds value to the project.

DHT11, DHT22, and BME280 are all available at Circuitkar — buy the DHT22 over the DHT11 in any project where data quality matters.