diff --git a/homeassistant/components/elkm1/models.py b/homeassistant/components/elkm1/models.py
index dfaf218942c..9f784951c11 100644
--- a/homeassistant/components/elkm1/models.py
+++ b/homeassistant/components/elkm1/models.py
@@ -7,7 +7,7 @@ from typing import Any
 from elkm1_lib import Elk
 
 
-@dataclass
+@dataclass(slots=True)
 class ELKM1Data:
     """Data for the elkm1 integration."""