diff --git a/homeassistant/components/sensibo/switch.py b/homeassistant/components/sensibo/switch.py
index ee9c946268fee8..cce72dfaae651a 100644
--- a/homeassistant/components/sensibo/switch.py
+++ b/homeassistant/components/sensibo/switch.py
@@ -151,9 +151,10 @@ def extra_state_attributes(self) -> Mapping[str, Any] | None:
     @async_handle_api_call
     async def async_turn_on_timer(self, key: str, value: bool) -> bool:
         """Make service call to api for setting timer."""
+        new_state = not self.device_data.device_on
         data = {
             "minutesFromNow": 60,
-            "acState": {**self.device_data.ac_states, "on": value},
+            "acState": {**self.device_data.ac_states, "on": new_state},
         }
         result = await self._client.async_set_timer(self._device_id, data)
         return bool(result.get("status") == "success")