diff --git a/homeassistant/components/sia/const.py b/homeassistant/components/sia/const.py
index 82ef6ad9429..537c106fefa 100644
--- a/homeassistant/components/sia/const.py
+++ b/homeassistant/components/sia/const.py
@@ -38,3 +38,4 @@ KEY_MOISTURE: Final = "moisture"
 KEY_POWER: Final = "power"
 
 PREVIOUS_STATE: Final = "previous_state"
+AVAILABILITY_EVENT_CODE: Final = "RP"
diff --git a/homeassistant/components/sia/sia_entity_base.py b/homeassistant/components/sia/sia_entity_base.py
index fee3c0b2262..311728ad578 100644
--- a/homeassistant/components/sia/sia_entity_base.py
+++ b/homeassistant/components/sia/sia_entity_base.py
@@ -14,7 +14,7 @@ from homeassistant.helpers.event import async_call_later
 from homeassistant.helpers.restore_state import RestoreEntity
 from homeassistant.helpers.typing import StateType
 
-from .const import DOMAIN, SIA_EVENT, SIA_HUB_ZONE
+from .const import AVAILABILITY_EVENT_CODE, DOMAIN, SIA_EVENT, SIA_HUB_ZONE
 from .utils import get_attr_from_sia_event, get_unavailability_interval
 
 _LOGGER = logging.getLogger(__name__)
@@ -105,7 +105,7 @@ class SIABaseEntity(RestoreEntity):
             return
         self._attr_extra_state_attributes.update(get_attr_from_sia_event(sia_event))
         state_changed = self.update_state(sia_event)
-        if state_changed:
+        if state_changed or sia_event.code == AVAILABILITY_EVENT_CODE:
             self.async_reset_availability_cb()
         self.async_write_ha_state()