Pick what you want to measure, tick what your project needs and see which sensors fit, best first, with all of them side by side. 39 sensors for ESP32, Arduino and Raspberry Pi Pico, with every figure from the makers’ datasheets.
The sensors that have everything you ticked, best first.
±0.2 °C · ±1.8 %RH · I²C · 1.08 to 3.6 V
Sensirion’s current generation: ±0.2 °C and ±1.8 %RH (SHT45: ±0.1 °C, ±1.0 %RH), 80 nA idle and a built-in heater.
Fits because: humidity ±1.8 %RH
Watch out: Runs from 1.08 to 3.6 V only, so no 5 V. The address (0x44, 0x45 or 0x46) depends on the part code, not on a pin.
±0.2 °C · ±2 %RH · I²C · 2.15 to 5.5 V
Sensirion’s well-proven sensor: ±0.2 °C, ±2 %RH, two I²C addresses and a supply from 2.15 to 5.5 V.
Fits because: humidity ±2 %RH
Watch out: The SHT4x is newer, smaller and more accurate on humidity for the same job.
±0.3 °C · ±2 %RH · I²C · 2 to 5.5 V
A small, low-cost I²C sensor with ±0.3 °C and ±2 %RH: the usual upgrade from a DHT22.
Fits because: humidity ±2 %RH
Watch out: Fixed address 0x38, so one per bus. In ESPHome, use the aht10 component with variant AHT20.
Mount humidity sensors in free air, away from the microcontroller and the regulator: a sensor 2 °C warmer than the room reads several %RH too low.
| Feature | SHT4x | SHT31 | AHT20 | BME280 | HDC1080 | Si7021 | HTU21D | TMP117 | DS18B20 | DHT22 | BME680 | DHT11 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Measures | temperature · humidity | temperature · humidity | temperature · humidity | temperature · humidity · pressure | temperature · humidity | temperature · humidity | temperature · humidity | temperature | temperature | temperature · humidity | temperature · humidity · pressure · gas (VOC) | temperature · humidity |
| Temperature accuracy | ±0.2 °C | ±0.2 °C | ±0.3 °C | ±1 °C | ±0.2 °C | ±0.3 °C | ±0.3 °C | ±0.1 °C | ±0.5 °C | ±0.5 °C | ±1 °C | ±2 °C |
| Humidity accuracy | ±1.8 %RH | ±2 %RH | ±2 %RH | ±3 %RH | ±2 %RH | ±2 %RH | ±2 %RH | No humidity | No humidity | ±2 %RH | ±3 %RH | ±5 %RH |
| Temperature range | −40 to 125 °C | −40 to 125 °C | −40 to 85 °C | −40 to 85 °C | – | −40 to 125 °C | −40 to 125 °C | −55 to 150 °C | −55 to 125 °C | −40 to 80 °C | −40 to 85 °C | 0 to 50 °C |
| Interface | I²C | I²C | I²C | I²C, SPI | I²C | I²C | I²C | I²C | 1-Wire | Single wire (own protocol) | I²C, SPI | Single wire (own protocol) |
| I²C address | 0x44, 0x45, 0x46 (set by the part code) | 0x44, 0x45 (set with a pin) | 0x38 | 0x76, 0x77 (set with a pin) | 0x40 | 0x40 | 0x40 | 0x48, 0x49, 0x4A, 0x4B (set with a pin) | Not I²C | Not I²C | 0x76, 0x77 (set with a pin) | Not I²C |
| Supply | 1.08 to 3.6 V | 2.15 to 5.5 V | 2 to 5.5 V | 1.71 to 3.6 V | 2.7 to 5.5 V | 1.9 to 3.6 V | 1.5 to 3.6 V | 1.7 to 5.5 V | 3 to 5.5 V | 3.3 to 6 V | 1.71 to 3.6 V | 3 to 5.5 V |
| Current between readings | 0.08 µA | 0.2 µA | 0.25 µA | 0.1 µA | 0.1 µA | 0.06 µA | – | 0.15 µA | 0.75 µA | 50 µA | 0.15 µA | 100 µA |
| ESPHome | sht4x | sht3xd | aht10 | bme280_i2c / bme280_spi | hdc1080 | htu21d | htu21d | tmp117 | dallas_temp | dht | bme680 | dht |
| Status | Available | Available | Available | Available | Available | Discontinued | Available | Available | Available | Available | Available | Available |
Typical figures from the makers’ datasheets and product pages. “–”: not in the sources we checked. Supply: the chip or module itself; breakout boards often add a regulator and level shifting.
Temperature and humidity: DHT22 vs BME280 DHT11 vs DHT22 AHT20 vs DHT22 DHT22 vs SHT31 SHT31 vs SHT4x AHT20 vs SHT31 DS18B20 vs DHT22 BME680 vs BME280
Pressure: BME280 vs BMP280 BMP280 vs BMP390
Distance: VL53L0X vs VL53L1X HC-SR04 vs VL53L0X HC-SR04 vs JSN-SR04T VL53L1X vs TF-Luna
Light: BH1750 vs TSL2561 BH1750 vs VEML7700
CO₂ and air quality: SCD40 vs MH-Z19C SCD40 vs SCD30 SCD40 vs SCD41 SGP30 vs SGP40 ENS160 vs CCS811 PMS5003 vs SDS011
Start from what you need to know, not from the sensor in your kit. A room thermometer is fine at ±0.5 °C; mould prevention or a greenhouse is worth a ±2 %RH humidity sensor; a weather station that compares pressure with forecasts needs good absolute accuracy, while an altimeter needs good relative accuracy.
Then check how it connects. I²C sensors share two wires with other devices as long as their addresses differ; the DHT11 and DHT22 use their own single-wire protocol, the DS18B20 uses 1-Wire, and most CO₂ and particle sensors use a UART. On ESP32 and Raspberry Pi Pico boards, prefer sensors that run from 3.3 V or whose data lines work at 3.3 V.
Relative humidity depends on temperature: a sensor 2 °C warmer than the room reads several %RH too low, whatever its datasheet says. Put it away from the microcontroller, the regulator and the Wi-Fi antenna, ideally on a short cable or in a vented enclosure, and keep it out of direct sun.
The DHT11 and DHT22 are cheap and easy, but slow and less accurate. The AHT20, SHT31, SHT4x, HTU21D, Si7021 and HDC1080 are I²C sensors with ±0.2 to ±0.3 °C typical; of these, the SHT4x is the most accurate on humidity. The BME280 adds pressure at the cost of some accuracy, and the DS18B20 and TMP117 measure temperature only.
NDIR and photoacoustic sensors (MH-Z19C, SCD30, SCD40, SCD41) measure CO₂ itself, which tells you when a room needs air. Metal-oxide sensors (SGP30, SGP40, SGP41, ENS160, CCS811, BME680) react to volatile organic compounds: some estimate an “eCO₂” from them, but that isn’t a CO₂ measurement. They are good at spotting cooking, cleaning products or paint, and they are smaller and cheaper.
Ultrasonic modules such as the HC-SR04 have a wide beam and work on glass and dark surfaces, but soft materials absorb the echo. Laser time-of-flight sensors (VL53L0X, VL53L1X, VL53L4CD) and the TF-Luna LiDAR have a narrow beam and read small targets, but sunlight and dark surfaces cut their range. For water tanks, the waterproof JSN-SR04T is the usual choice.
Each I²C sensor links to its page in the I²C address list, with wiring, pull-ups and conflicts. For battery projects, add the sensor’s current to the rest of the board in the battery life calculator.
Sources: the makers’ datasheets and product pages (Sensirion, Bosch Sensortec, Texas Instruments, Analog Devices, Silicon Labs, TE Connectivity, Aosong, Infineon, STMicroelectronics, Benewake, Sharp, ROHM, ams OSRAM, Vishay, Winsen, ScioSense, Plantower, Nova Fitness) and the ESPHome documentation, checked in November 2026.
For accuracy, a Sensirion SHT4x or SHT31 on I²C: ±0.2 °C and ±1.8 or ±2 %RH typical. The AHT20 costs less and comes close (±0.3 °C, ±2 %RH). Choose the BME280 if you also want pressure, and keep the DHT22 for simple projects. Whatever you pick, mount it away from the board’s warm parts.
The DHT22 is specified at ±0.5 °C and ±2 %RH typical, the BME280 at ±1 °C (±0.5 °C at 25 °C) and ±3 %RH. The BME280 adds pressure, works on I²C or SPI and draws 0.1 µA in sleep against about 50 µA, so it suits battery projects; the DHT22 is slow and uses its own single-wire protocol. For accurate humidity, an SHT4x beats both.
Usually because it is warmer than the room. Relative humidity falls as temperature rises, so a sensor heated by the microcontroller, the regulator or the sun reads too dry. Move it away from the board, on a short cable or in a vented enclosure, and compare it with another sensor after a few minutes.
No. They are metal-oxide gas sensors that react to volatile organic compounds and estimate an “eCO₂” from them. To know the real CO₂ level, for example to decide when to air a room, use an NDIR or photoacoustic sensor such as the SCD40, SCD41, SCD30 or MH-Z19C.
The HC-SR04 reaches 4 m with a wide beam and sees glass, but it needs 5 V and a divider on its echo pin for 3.3 V boards. The VL53L0X is a small laser sensor on I²C at 3.3 V with a narrow beam: about 1.2 m on white indoors, up to 2 m in the dark, and less in sunlight. For water tanks, use the waterproof JSN-SR04T.
Only if the sensor lets you change it: many have an address pin (BME280, SHT31, TMP117), the VL53 sensors can be renumbered in software, and on the SHT4x the address depends on the part code. Otherwise use a multiplexer such as the TCA9548A, or a second I²C bus on the ESP32.
Most have an official ESPHome component, named in the table. The VL53L1X, the VL53L4CD and the Sharp GP2Y0A21 don’t; the Sharp sensor can still be read with the adc component. This site’s ESPHome generator writes the configuration for the DHT11, DHT22, BME280, SHT3x and DS18B20.