diff --git a/pyhilo/device/__init__.py b/pyhilo/device/__init__.py
index 22e3124..ce48ade 100644
--- a/pyhilo/device/__init__.py
+++ b/pyhilo/device/__init__.py
@@ -5,6 +5,8 @@
 from datetime import datetime
 from typing import TYPE_CHECKING, Any, Dict, Union, cast
 
+from homeassistant.const import STATE_UNKNOWN
+
 from pyhilo.const import (
     HILO_DEVICE_ATTRIBUTES,
     HILO_LIST_ATTRIBUTES,
@@ -150,7 +152,7 @@ def has_attribute(self, attr: str) -> bool:
         return next((True for k in self.supported_attributes if k.attr == attr), False)
 
     def get_value(
-        self, attribute: str, default: Union[str, int, float, None] = None
+        self, attribute: str, default: Union[str, int, float, None] = STATE_UNKNOWN
     ) -> Any:
         attr = self.get_attribute(attribute)
         return attr.value if attr else default