diff --git a/hasspy/mqtt.py b/hasspy/mqtt.py
index c78fc7a..e2d70ff 100644
--- a/hasspy/mqtt.py
+++ b/hasspy/mqtt.py
@@ -168,7 +168,7 @@ class HassSystemClient(HassClient):
     @property
     def state_payload(self) -> dict[str, Any]:
         return {
-            "power": self.power_on,
+            "power": "POWER_ON" if self.power_on else "POWER_OFF",
         }