Updated code as per comment in #60676 (#60682)

* Minor code refactor

homeassistant/components/izone/climate.py

@@ -207,10 +207,9 @@ class ControllerDevice(ClimateEntity):
             """Handle controller data updates."""
             if ctrl is not self._controller:
                 return
+            if not self.available:
+                return
             self.async_write_ha_state()
-            for zone in self.zones.values():
-                if zone.hass is not None:
-                    zone.async_schedule_update_ha_state()
 
         self.async_on_remove(
             async_dispatcher_connect(
@@ -492,6 +491,21 @@ class ZoneDevice(ClimateEntity):
     async def async_added_to_hass(self):
         """Call on adding to hass."""
 
+        @callback
+        def controller_update(ctrl: Controller) -> None:
+            """Handle controller data updates."""
+            if ctrl.device_uid != self._controller.unique_id:
+                return
+            if not self.available:
+                return
+            self.async_write_ha_state()
+
+        self.async_on_remove(
+            async_dispatcher_connect(
+                self.hass, DISPATCH_CONTROLLER_UPDATE, controller_update
+            )
+        )
+
         @callback
         def zone_update(ctrl: Controller, zone: Zone) -> None:
             """Handle zone data updates."""