diff --git a/src/core/entity.py b/src/core/entity.py
index 088370e..3c7442e 100644
--- a/src/core/entity.py
+++ b/src/core/entity.py
@@ -5,7 +5,7 @@ class Entity:
         self._id = id
         self._name = name
         self._room = room
-        self._device_type = device_type
+        self._device_type = device_type.strip().lower()
         self._groups = set(groups)
         self.__is_on__: bool | None = None