diff --git a/custom_components/versatile_thermostat/climate.py b/custom_components/versatile_thermostat/climate.py
index 404b54fc..d1a08b1d 100644
--- a/custom_components/versatile_thermostat/climate.py
+++ b/custom_components/versatile_thermostat/climate.py
@@ -810,7 +810,9 @@ async def _async_max_power_changed(self, event):
         _LOGGER.debug(event)
         new_state = event.data.get("new_state")
         old_state = event.data.get("old_state")
-        if new_state is None or new_state.state == old_state.state:
+        if new_state is None or (
+            old_state is not None and new_state.state == old_state.state
+        ):
             return
 
         try: