Wi-Fi temperature and humidity sensors have the advantage of not requiring a hub, as is the case with Zigbee and Z-Wave, or an ESP32, as seen with the Bluetooth sensors from Xiaomi. Instead, they connect directly to your access point and can either be configured using a built-in web server, or more likely using an app. Even though there aren't many models available, I have done some research a put together a list of the best Wi-Fi temperature and humidity sensors that integrate with Home Assistant.
Shelly H&T: Battery or cable, you decide
If you don’t want or a have a Zigbee hub and keep all your sensors connected via Wi-Fi, the Shelly H&T might be for you. The Shelly H&T is considerably bigger than the Aqara Temperature and Humidity Sensor because Wi-Fi is a lot more power-hungry than Zigbee, and thus it requires a larger battery. On battery, the Shelly H&T will last about 16 months, but it can also be powered with a USB power supply, making it more flexible than other sensors. Unfortunately, the USB port is not USB-C, but Micro-USB.
- Can be connected to a Wi-Fi network, without the need of any additional controller.
- Uses a CR123A battery, with a life of up to 16 months.
- Can be powered from the mains using its Micro-USB port.
Personally, I don’t like the design of this sensor. Wi-Fi needs more power in comparison to Zigbee and BLE, so there's no way the Shelly H&T could run for an extended period on a single coin-cell battery. It looks big and bulky in comparison to the Aqara sensors I use. Those can be hidden away on a bathroom cabinet or stuck to the wall. The Shelly H&T will take some skill to hide.
All things considered, the Shelly H&T is the best Wi-Fi temperature and humidity sensor for Home Assistant. It can be battery-powered for over a year, it connects locally, and doesn't require a hub. It is also the way to go if you are seeking continuous updates from the sensor. When connect to the mains, the Shelly H&T doesn't require any power-saving.
Sonoff TH16: Temperature and humidity monitoring add-on
While it strictly isn't just a temperature and humidity sensor, the TH16 from Sonoff is a smart switch, to which a sensor can be attached. It comes with either a Si7021 sensor, which can precisely measure ambient temperature (±0.4 °C) and humidity (±3% RH).
The second version has a waterproof DS18B20 temperature sensor. The easiest way to integrate these switches and their sensors with Home Assistant is by using the SonoffLAN custom component.
Qingping Air Monitor Lite: Limited battery life
The Qingping Air Monitor Lite not only monitors the temperature and humidity of a room, but also CO2, PM2.5, and PM10 particles. The price reflects those features, so I wouldn't put this device anywhere near the top of the best Wi-Fi temperature and humidity sensors for Home Assistant, but it does deserve a mention. Partially because it is one of the best-looking temperature and humidity monitors.
- Monitors PM2.5, PM10, CO2, temperature, and humidity.
- Uses a PlanTower laser-scattering particle sensor, a SenseAir CO2 sensor, and a Sensirion temperature and humidity sensor.
- Has a clear OLED screen, enabling a wider visible angle. Through the multicoloured indicator, you will know the air quality, the temperature, and the humidity level, with a glance from a distance.
- You can tap or slide the touch bar on the top to switch the readings as smoothly as to operate a touch screen.
While the Qingping Air Monitor Lite does include a battery, making it one of the few Wi-Fi temperature and humidity sensors that does, it will only last for seven hours. Even though the battery has a capacity of 2000 mAh (that's only slightly lower than the iPhone 12 mini), the sensors and connection will burn through it quickly.
I could see this sensor being useful for those working from home. You could plug it in overnight and monitor the air quality, temperature, and humidity while you sleep, and in the morning, place it on your desk. The CO2, PM2.5, and PM10 readings will give you an extra insight as to when your window should be opened.
To integrate the Qingping Air Monitor Lite with Home Assistant, the HomeKit Controller can be utilized. Sadly, you will need an iOS device to complete the setup, as can be seen in this guide. Alternatively, the Xiaomi MIoT custom component can be installed using HACS, and the Qingping Air Monitor Lite integrated using this configuration shared in the Home Assistant Community.
Awair Glow C: Temperature and humidity monitoring, plus nightlight and smart switch
The Awair Element is similar to the Sonoff TH16 in that it is both a temperature and humidity monitor and also a smart switch. The Glow C does, however, have a few additional features: In addition to temperature and humidity, it can also monitor airborne toxic chemicals (VOCs), and it has a built-in smart light.
- Track airborne toxic chemicals (VOCs), humidity, and temperature levels in your space.
- Choose from hundreds of light colours and customize your device settings to use Glow C as a smart night light.
Inside the Awair Element, there are a pair of Sensirion sensors, which are known for their high accuracy. Unfortunately, the integration with Home Assistant relies on cloud polling, making it reliant on an internet connection and slower than any local integration.
Wi-Fi humidity and temperature sensors built using ESPHome
If the sensors listed above don't fit your requirements, you have the option of building your sensors. As it will be built to spec, it will obviously be the best Wi-Fi temperature and humidity sensor for your Home Assistant. Simply grab yourself an affordable ESP8266 or ESP32 board and a BME260 temperature sensor, wire them up, and write the firmware. You can write the code for such a custom sensor in no time thanks to ESPHome.
Building your sensors can be a fun project and is certainly more rewarding than just opening a cardboard box and pushing a button to get the sensor connected. Just keep in mind that ESPHome isn’t best suited for battery-powered devices, and it might take some tinkering to get things working perfectly. Examples of makers building battery-powered sensors are to be found, which might inspire you.
A DIY temperature and humidity sensor powered by ESPHome will more than likely have to be powered from the wall. On the bright side, this does allow for continuous recording. And because you are using ESPHome, you aren’t restricted to just using one sensor. You could also hook up more sensors, attach some LEDs, or use it for presence detection.
If you do want to go down the DIY route, I have an article on why the BME280 is currently the best temperature and humidity breakout module for your DIY electronics projects. Whatever you do, do not cheap out and go for the DHT11 or DHT22. I promise, you will regret it. You can also get yourself a BME680 if you want to be able to measure air quality too.