Quick Summary Ecobee thermostats frequently drop HomeKit connections because of IP address changes (the thermostat gets a new IP and HomeKit loses track of it)…
Quick Summary
Ecobee thermostats frequently drop HomeKit connections because of IP address changes (the thermostat gets a new IP and HomeKit loses track of it), router firmware updates that reset mDNS settings, or HomeKit's Bonjour discovery protocol failing on certain routers. The fix in most cases is assigning the Ecobee a static IP address and re-pairing it with HomeKit.
Step 1: Restart the Ecobee and Your Home Hub
Start with the simplest fix. Restart the Ecobee: Ecobee menu → Settings → Reset → Restart Thermostat. Restart your Apple TV, HomePod, or iPad (whichever is your HomeKit hub). Wait 3 minutes. Check the Home app — does the Ecobee show as connected?
If yes: the issue was a temporary communication failure. If it keeps happening: proceed to Step 2.
Step 2: Assign a Static IP to the Ecobee
HomeKit uses the device's IP address to communicate. If the IP changes (which happens with DHCP), HomeKit loses the connection. Log into your router admin panel (usually 192.168.1.1). Find the DHCP reservation or static IP section. Find the Ecobee's MAC address: Ecobee menu → Settings → Wi-Fi → Connected Network → note the MAC address. Create a DHCP reservation for this MAC address with a fixed IP (e.g., 192.168.1.150). Save and restart the router. Restart the Ecobee. Check if HomeKit connection is stable.
Step 3: Check Router mDNS/Bonjour Settings
HomeKit uses mDNS (Bonjour) to discover devices. Some routers block or limit mDNS traffic. Log into your router admin panel. Search for "mDNS," "Bonjour," or "Multicast" settings. Ensure mDNS is enabled. If you have a guest network: ensure the Ecobee and your Apple devices are on the same network (not one on main, one on guest). If you have VLANs: ensure mDNS is bridged between the IoT VLAN and the main VLAN.
Step 4: Remove and Re-Pair with HomeKit
If the connection keeps dropping, a fresh HomeKit pairing often resolves persistent issues. Apple Home app → tap the Ecobee → scroll down → Remove Accessory. On the Ecobee: Settings → Smart Home → Apple HomeKit → Reset HomeKit. Re-pair: Apple Home app → + → Add Accessory → scan the HomeKit code on the Ecobee (Settings → Smart Home → Apple HomeKit → HomeKit Code). Test the connection over 24 hours.
Step 5: Update Ecobee Firmware Ecobee menu → Settings → About → check firmware version. Compare with the latest version at ecobee.com/support. If an update is available: Ecobee updates automatically when connected to Wi-Fi. Ensure the thermostat is connected and wait overnight.