Household gas leaks are one of the most insidious home hazards: invisible, often odorless (despite odorants), and the consequences can be catastrophic. Xiaomi’s gas alarm (MiJia Honeywell or Aqara Gas Leak Detector) solves this problem by combining precise sensor technology with integration into the smart home ecosystem. But how exactly does it detect a threat? Why does it work before you smell? And why can’t it be installed in the bathroom?
In this article, we will take a closer look at how Xiaomi’s gas sensor works, from sensor physics to alert algorithms, and how to connect, test and maintain it properly, what gases it detects (and what it doesn’t!), how it distinguishes leakage from false alarms, and why it can’t be used in forced-ventilated rooms without additional settings, and finally, a checklist for the installation and answers to frequent questions that aren’t covered even in official instructions.
How Xiaomi Sensor Detects Gas: Physics and Technology
The signaling device is based on a semiconductor sensor (most often based on tin dioxide, SnO₂), It's a reaction to gas molecules by changing the electrical resistance, and when the concentration of gas in the air exceeds a threshold, it triggers an alarm?
Key features of the Xiaomi sensor:
- 🔬 Selectivity: the sensor is tuned to detect natural gas (methane, CH₄) carbon monoxide (CO), But it doesn't respond to propane-butane (it needs a separate sensor.
- ⚡ Low power consumption: the sensor is only activated 1-2 moment-by-second 10 minutes, which extends the battery life to 5-7 years.
- 📉 Calibration: In the first 24 hours after installation, the sensor “accustomed” to the background level of gas in the room (for example, from the stove.
Interestingly, Xiaomi's sensor not only detects gas, but also analyzes the dynamics of the change in concentration. If the gas level rises rapidly (for example, when a pipe breaks), the alarm will arrive earlier than in a slow leak, which avoids false positives from short-term jumps (for example, when the stove is turned on).
What gases do you detect (and what they don’t!)
This is one of the most common questions users have. the sensor Xiaomi MiJia Honeywell (model JTYJ-GD-01LM/BW) is certified for detection:
| Type of gas | Formula | Efficiency threshold | Notes |
|---|---|---|---|
| Natural gas (methane) | CH₄ | 10% of the lower explosive limit (LDP) | Main gas in urban networks |
| Carbon monoxide (carbon monoxide) | CO | 50 ppm (parts per million) | Dangerous even in small concentrations |
| Liquefied gas (propane-butane) | C₃H₈ / C₄H₁₀ | — | It's not detectable, we need a separate sensor. |
| Ammonia | NH₃ | — | No sensitivity data |
⚠️ Note: If you use gas cylinders (for example, in the country), the Xiaomi sensor is not suitable - it does not recognize propane butane. In this case, look for specialized models, such as Elgato Eve Smoke or Netatmo Smart Smoke Alarm (although they do not integrate with the Mi Home).
Another thing that's not clear is that the sensor doesn't recognize the source of the gas, and it's going to work for leaks from the pipe, for the stove to burn, for cigarette smoke (if the CO concentration is high), so it's important to choose the right place to put it, which is what we're going to talk about in the next section.
Where and how to install: 5 safety rules
If you place the sensor incorrectly, it can be zero in efficiency.
- Height: Natural gas (methane) is lighter than air, so the sensor is mounted on the wall at a height of 30 cm from the ceiling. For carbon monoxide (CO), which has a similar density to air, a height of 1.5-1.7 m from the floor is suitable.
- Distance from gas sources: no closer than 1 meter from the stove, boiler or gas column, but no further than 4 meters (otherwise the gas may not reach the sensor).
- Prohibited areas: 🚫 In the bathroom (high humidity spoils the sensor). 🚫 Near windows, fans or air conditioners (draughts can "blow" gas past the sensor). 🚫 In rooms with temperatures below 0°C or higher than 50°C.
Firming
Post-installation testing
test-gas
☑️ Pre-installing check
⚠️ Note: If the sensor is installed in a room with forced ventilation (for example, a kitchen with a high-power hood), set the Mi Home setting Sensitivity to maximum. Otherwise, the gas can be "pulled" out of the detection zone before the alarm goes off.
Integration with a smart home: what to do when triggered
Xiaomi sensor doesn’t just beep – it can automatically turn off the gas, turn on the hood or send SOS-To do this, you need to properly configure scripts in the Mi Home or Aqara Home app.
Here are the automations that are worth creating:
- 🔊 Local alarm: When triggered, the sensor makes an 85 dB sound (louder than an alarm clock) that is a basic function that does not require Internet access.
- 📱 Push notifications: Set up alerts on all family members’ phones via Mi Home → Smart. → Automation → If the gas sensor is triggered → Send a notification.
- 🔌 Gas shutdown: If you have an electromagnetic valve installed (e.g. Xiaomi Aqara Valve Controller), create a scenario for it to close when a leak occurs.
- 💨 Turning on the hood: connect a smart socket (for example, Xiaomi Smart Plug) to the hood and program its turn on at full power.
Example of setting up automatic gas shutdown:
1. Open Mi Home → Smart → Automation → Create → If...
2. Select "Gas Sensor → Excess detected".
3. Add the action: "Aqara Valve Controller → Close the valve."
4. Save the script and test it.💡
If you don’t have an electromagnetic valve, use a smart socket to turn off the stove (if it’s electric) or set up a scenario to turn on all the fixtures in the house – this will help you quickly navigate at night.
⚠️ Warning: If the sensor is working, do not try to look for a leak using an open fire (matches, lighters)! Use a soap solution (apply to pipe connections - bubbles will indicate a leak) or a special gas analyzer. Before checking, ventilate the room for 10-15 minutes.
False positives: why the sensor is lying and what to do
Even the most accurate sensors sometimes get it wrong, and here are the most common causes of false alarms and ways to fix them:
| Reason. | How it manifests | Decision |
|---|---|---|
| High humidity | It works in the bathroom or after cooking. | Move the sensor away from the steam sources |
| Aerosols (freshers, deodorants) | Anxiety after spraying | Use aerosols in another room |
| Dust or dirt on the sensor | Frequently triggered for no apparent reason | Clean the sensor with a dry soft brush |
| Low battery charge | Short-term signals every few days | Replace the battery (CR123A) |
If false positives are repeated, check the sensor signal level in the Mi Home app:
- Open the device in the list.
- See the sensor signal (should be in the range of 20–80%).
- If the value is below 10% or above 90%, the sensor requires calibration (contact the service center) or replacement.
What if the sensor does not work for a real leak?
Maintenance and Replacement: How to Prolong the Life of a Sensor
The average life of a sensor is 5 to 7 years, but if properly maintained, it can last longer.
- 🧹 Cleaning: once every 3 months, wipe the body and vents with a dry soft cloth!
- 🔋 Battery: Replace the battery CR123A Every 1-2 years (even if the sensor is still working), a discharged battery can lead to false positives.
- 📡 Software Update: Check for updates in the Mi Home app. Firmware often improves detection algorithms.
- 📅 Testing: once every six months, check the sensor with test gas or smoke (from a fading match).
⚠️ Warning: If the sensor has been in operation for more than 7 years, it must be replaced, even if it is externally serviceable. The sensor loses sensitivity over time due to "poisoning" by gas molecules, and its reaction becomes unpredictable. The case of the device usually shows the date of production - count the service life from it.
When you change the sensor, look for dual-sensor models like the Aqara Gas Leak Detector T1, which detect both methane and carbon monoxide, which are more expensive but more reliable for kitchens with a gas stove and a speaker.
💡
The gas sensor is not a "put and forget" sensor, it needs to be tested every six months, cleaned every quarter and replaced every 5-7 years, even if it looks good.