Xiaomi’s AC Bridge: What it is, why it is needed and how it works in a smart home

If you’re using Xiaomi’s smart devices, from Yeelight light bulbs to robot vacuum cleaners, you’ve probably come across the term AC Bridge, which isn’t just another gadget in the company’s lineup, but a key element of the ecosystem that keeps the smart home running smoothly, and without it, many devices will either be unable to connect to the network or will be out of order.

In this article, we’ll look at what AC Bridge is in the context of Xiaomi, how it differs from conventional hubs (such as the Mi Home Hub), and why some users confuse it with routers or signal repeaters. You’ll also learn which Xiaomi devices require Bridge, and which can do without it – and what happens if you ignore this requirement.

Spoiler: If you have a Xiaomi air conditioner or a Wi-Fi + Zigbee smart socket at home, this article will help you avoid the typical setup errors. And we’ll also show you how to get around the limit on the number of connected devices to a single Bridge (this is true for owners of large smart homes).

What is the AC Bridge in Xiaomi’s ecosystem?

AC Bridge is a specialized device from Xiaomi that acts as an intermediary between smart gadgets and your home network. Unlike classic hubs (for example, Aqara Hub or Mi Home Hub), which work on the Zigbee or Z-Wave protocol, AC Bridge is most often used for devices that connect over Wi-Fi, but require additional authentication or management.

Simply put, it’s a “translator” between your router and smart devices that can’t communicate directly with the Mi Home app. For example, some Xiaomi air conditioners or Mi Smart Plug smart outlets require a connection via AC Bridge to:

  • 🔌 Provide stable connection (no breaks when switching routers).
  • 🔒 Protect data from interception (additional traffic encryption).
  • 📶 Expand coverage for devices with weak Wi-Fi signal.
  • 🤖 Make it easier to manage through voice assistants (Alice, Google Assistant).

It’s important not to confuse AC Bridge with Mi Wi-Fi Repeater or Mi Router, which simply amplifies the network, and Bridge also manages connected devices by syncing them with the Xiaomi cloud.

📊 What Xiaomi Smart Devices Are in Your Home?
Air conditioner
Yeelight bulbs
Robot vacuum cleaner
Smart sockets
Sensors (movements, temperatures)
Other

Why you need AC Bridge: basic functions

AC Bridge solves three key issues of Xiaomi smart homes:

  1. Compatibility: Some devices (such as Xiaomi Mi Air Conditioner air conditioners) cannot connect directly to the Mi Home due to protocol limitations.
  2. Stability: Devices connected via Bridge are less likely to lose connection to the server, even if the router has rebooted.
  3. Traffic between the device and the Xiaomi cloud is encrypted at Bridge level, which reduces the risk of hacking.

Without AC Bridge, you may face the following problems:

  • ❌ Smart air conditioner does not respond to commands from the app.
  • ❌ The Mi Smart Plug is disconnected from the network after the router is upgraded.
  • ❌ Voice commands (Alice, Siri) don't work with some devices.

💡

If your Xiaomi device requires AC Bridge but you haven't connected it, check the Devices section → Add → Other in the Mi Home app. There may be a hidden item for manually connecting over the bridge.

What Xiaomi devices require AC Bridge?

Not all Xiaomi gadgets need an AC Bridge, here’s a complete list of devices that require it (as of 2026):

Type of deviceModelProtocolNote
Air conditionerMi Air Conditioner (all models)Wi-Fi + IRWithout Bridge, it only works manually.
Smart socketMi Smart Plug (Zigbee + Wi-Fi)Zigbee 3.0Requires Bridge to integrate with Mi Home.
Air purifierMi Air Purifier Pro HWi-FiBridge is for remote control.
Smart fanMi Smart Fan 2Wi-Fi + BLEWithout it, Bridge will not sync with other devices.

Here are some devices that don’t require AC Bridge:

  • 💡 Yeelight light bulbs (connect directly to Wi-Fi).
  • 🤖 Mi Robot Vacuum Robots (using Wi-Fi + Lidar)
  • 🔐 Aqara sensors (operate via their own hub).
Why do some Xiaomi devices not work without Bridge?
It's about the data exchange protocol, for example, Xiaomi air conditioners use a proprietary protocol to control a compressor that is not compatible with standard Wi-Fi. Bridge "transfers" commands from the application to a format that is understandable for the device.

How to connect AC Bridge to smart devices?

The AC Bridge connection process consists of 5 steps, and it is important to follow them in order, otherwise the devices may not sync.

Turn Bridge on (blue light should come on)|Open the Mi Home app and press + → Add Device |Select Bridge category |Follow the on-screen instructions (QR- code scan may be required)|Plug the smart device to Bridge via Devices section →Add-->

If AC Bridge is not detected in the app, try:

  1. Reboot the router and the Bridge device itself (pull out the plug for 10 seconds).
  2. Make sure your router is running at 2.4GHz (not all Bridge models support 5GHz).
  3. Update the Mi Home app to the latest version (older versions may not support new devices).

⚠️ Warning: If your smart device still doesn't work after connecting AC Bridge, check if your router is blocking traffic to ports 8080 and 443. Some providers (such as Rostelecom) are defaulting to shutting them down for "unknown" devices.

AC Bridge vs Mi Home Hub: What's the difference?

Many users confuse AC Bridge with Mi Home Hub (or Aqara Hub).

ParameterAC BridgeMi Home Hub
Principal appointmentBridge for Wi-Fi devices with proprietary protocolsCentral hub for Zigbee/Z-Wave devices
Supported devicesAir conditioners, sockets, air purifiersSensors, light bulbs, switches.
Does it require a connection to the router?Yes (on Wi-Fi or Ethernet)Yes (only on Ethernet)
Support for voice assistantsYes (Alice, Google Assistant)Yes, but with limitations for some devices.

Can you use both devices at the same time?

  • 🔄 AC Bridge and Mi Home Hub are not in conflict.
  • 📡 However, if you have a weak router, it is better to connect them to different networks (for example, Bridge is to 2.4 GHz, and Hub is to 5 GHz).
  • 🔌 Some devices (e.g., smart light bulbs) may “hang” if connected to both hubs at the same time.

💡

If you already have a Mi Home Hub, it doesn't mean you don't need an AC Bridge, but it's different and doesn't replace each other.

Common AC Bridge Problems and How to Solve Them

Even with the right AC Bridge connection, there can be failures, and here are the most common ones and ways to fix them:

1.The Bridge is not connected to Wi-Fi

Reasons:

  • 🔴 The router only operates in 5GHz mode (switch to 2.4GHz or switch on mixed mode).
  • 🔴 The WPA2-PSK protocol is disabled in the router settings (required for Bridge).
  • 🔴 IP- Bridge address conflicts with another device (try assigning static IP in router settings).

2.Smart devices are disconnected from Bridge

Decisions:

  • 🔄 Reboot Bridge (pull out the plug for 30 seconds).
  • 📶 Check the Wi-Fi signal level at the Bridge installation site (must be at least 70%).
  • 🔧 Update Bridge firmware through the Mi Home app (Settings section → Software Update).

3.Bridge not visible in Mi Home app

What to do:

  • 📱 Delete the cache of the Mi Home app (on Android: "Settings" → "Applications" → "Mi Home" → "Storage" → "Clean up the cache").
  • 🌐 Check to see if the antivirus or firewall is blocking access to Xiaomi servers.
  • 🔄 Try connecting Bridge via another smartphone or tablet.

⚠️ Warning: If after all the manipulations AC Bridge still doesn't work, check if it's connected to the network via VPN or a proxy. Some models block traffic if they detect a "non-standard" connection.

Can you do without the AC Bridge?

Technically, yes, but with reservations.

  1. Direct Wi-Fi connectivity: Some devices (such as Yeelight light bulbs) can work without Bridge but lose some of the features (such as voice control or automatic firmware updates).
  2. Using third-party hubs: For example, Home Assistant or OpenHAB can replace AC Bridge, but require customization and programming knowledge.
  3. IR- Remote Controller: For air conditioners, you can use the Mi IR Remote Controller, but this is less convenient than controlling through Bridge.

But there's a caveat: without AC Bridge, you can't use some of the features of Xiaomi's ecosystem, like time automation or a bunch of devices in a scenario, for example, if you want the air conditioner to turn on when you open a window (with an Aqara sensor), without Bridge, you can't.

💡

If you do decide to do without AC Bridge, check if your device supports the Tuya protocol, in which case it can be connected via the Smart Life app instead of Mi Home.

FAQ: Frequent questions about Xiaomi’s AC Bridge

🔹 Can devices from different brands (e.g. Xiaomi and Aqara) be connected to one AC Bridge?
No, AC Bridge only works with Xiaomi devices certified for the Mi Home ecosystem. Aqara requires a separate hub (like the Aqara Hub M2). However, you can use both hubs at the same time if you connect them to the same Mi Home app.
🔹 How many devices can be connected to one AC Bridge?
The official limit is 32 devices per Bridge, but in practice, if you have more than 20 devices, you can have delays in executing commands, and if you have a large smart home network, you'd better install a second AC Bridge and spread the load.
🔹 Does AC Bridge work without internet?
Yes, but with limitations. Local control (via the Mi Home app on the same network) will work, but the following features will become unavailable: Remote control from outside the home; Voice commands via Alice or Google Assistant; Automatic firmware updates.
🔹 Can I use AC Bridge with a router from another manufacturer (not Xiaomi)?
Yes, AC Bridge is compatible with any routers that support Wi-Fi 802.11 b/g/n at 2.4 GHz. However, for stable operation, it is recommended: Disable Smart Connect on the router. Reserve IP- address for Bridge in the DHCP settings. Disable energy saving mode on the router (if any).
🔹 How to reset AC Bridge to factory settings?
To reset, press and hold the button on the AC Bridge case for 10 seconds until the indicator flashes yellow quickly, and then the device returns to factory settings and can be reconnected. ⚠️ Attention: Reset will remove all devices connected to the Bridge. They will have to be reconfigured!