diff --git a/homeassistant/components/simplisafe/__init__.py b/homeassistant/components/simplisafe/__init__.py
index 0c0595896ed..2514c5e9ed9 100644
--- a/homeassistant/components/simplisafe/__init__.py
+++ b/homeassistant/components/simplisafe/__init__.py
@@ -22,7 +22,11 @@ from homeassistant.helpers import (
     config_validation as cv,
     device_registry as dr,
 )
-from homeassistant.helpers.dispatcher import async_dispatcher_send
+from homeassistant.helpers.dispatcher import (
+    async_dispatcher_connect,
+    async_dispatcher_send,
+)
+from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.event import async_track_time_interval
 from homeassistant.helpers.service import verify_domain_control
 
@@ -240,3 +244,73 @@ class SimpliSafe:
         tasks = [self._update_system(system) for system in self.systems.values()]
 
         await asyncio.gather(*tasks)
+
+
+class SimpliSafeEntity(Entity):
+    """Define a base SimpliSafe entity."""
+
+    def __init__(self, system, name, *, serial=None):
+        """Initialize."""
+        self._async_unsub_dispatcher_connect = None
+        self._attrs = {ATTR_SYSTEM_ID: system.system_id}
+        self._name = name
+        self._online = True
+        self._system = system
+
+        if serial:
+            self._serial = serial
+        else:
+            self._serial = system.serial
+
+    @property
+    def available(self):
+        """Return whether the entity is available."""
+        # We can easily detect if the V3 system is offline, but no simple check exists
+        # for the V2 system. Therefore, we mark the entity as available if:
+        #   1. We can verify that the system is online (assuming True if we can't)
+        #   2. We can verify that the entity is online
+        system_offline = self._system.version == 3 and self._system.offline
+        return not system_offline and self._online
+
+    @property
+    def device_info(self):
+        """Return device registry information for this entity."""
+        return {
+            "identifiers": {(DOMAIN, self._system.system_id)},
+            "manufacturer": "SimpliSafe",
+            "model": self._system.version,
+            "name": self._name,
+            "via_device": (DOMAIN, self._system.serial),
+        }
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return self._attrs
+
+    @property
+    def name(self):
+        """Return the name of the entity."""
+        return f"{self._system.address} {self._name}"
+
+    @property
+    def unique_id(self):
+        """Return the unique ID of the entity."""
+        return self._serial
+
+    async def async_added_to_hass(self):
+        """Register callbacks."""
+
+        @callback
+        def update():
+            """Update the state."""
+            self.async_schedule_update_ha_state(True)
+
+        self._async_unsub_dispatcher_connect = async_dispatcher_connect(
+            self.hass, TOPIC_UPDATE, update
+        )
+
+    async def async_will_remove_from_hass(self) -> None:
+        """Disconnect dispatcher listener when removed."""
+        if self._async_unsub_dispatcher_connect:
+            self._async_unsub_dispatcher_connect()
diff --git a/homeassistant/components/simplisafe/alarm_control_panel.py b/homeassistant/components/simplisafe/alarm_control_panel.py
index d44a1c7760a..bbd9a5d4e51 100644
--- a/homeassistant/components/simplisafe/alarm_control_panel.py
+++ b/homeassistant/components/simplisafe/alarm_control_panel.py
@@ -2,7 +2,7 @@
 import logging
 import re
 
-from simplipy.sensor import SensorTypes
+from simplipy.entity import EntityTypes
 from simplipy.system import SystemStates
 
 from homeassistant.components.alarm_control_panel import (
@@ -16,11 +16,10 @@ from homeassistant.const import (
     STATE_ALARM_ARMED_HOME,
     STATE_ALARM_DISARMED,
 )
-from homeassistant.core import callback
-from homeassistant.helpers.dispatcher import async_dispatcher_connect
 from homeassistant.util.dt import utc_from_timestamp
 
-from .const import DATA_CLIENT, DOMAIN, TOPIC_UPDATE
+from . import SimpliSafeEntity
+from .const import DATA_CLIENT, DOMAIN
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -33,7 +32,6 @@ ATTR_LAST_EVENT_SENSOR_TYPE = "last_event_sensor_type"
 ATTR_LAST_EVENT_TIMESTAMP = "last_event_timestamp"
 ATTR_LAST_EVENT_TYPE = "last_event_type"
 ATTR_RF_JAMMING = "rf_jamming"
-ATTR_SYSTEM_ID = "system_id"
 ATTR_WALL_POWER_LEVEL = "wall_power_level"
 ATTR_WIFI_STRENGTH = "wifi_strength"
 
@@ -55,18 +53,16 @@ async def async_setup_entry(hass, entry, async_add_entities):
     )
 
 
-class SimpliSafeAlarm(AlarmControlPanel):
+class SimpliSafeAlarm(SimpliSafeEntity, AlarmControlPanel):
     """Representation of a SimpliSafe alarm."""
 
     def __init__(self, simplisafe, system, code):
         """Initialize the SimpliSafe alarm."""
-        self._async_unsub_dispatcher_connect = None
-        self._attrs = {ATTR_SYSTEM_ID: system.system_id}
+        super().__init__(system, "Alarm Control Panel")
         self._changed_by = None
         self._code = code
         self._simplisafe = simplisafe
         self._state = None
-        self._system = system
 
         # Some properties only exist for V2 or V3 systems:
         for prop in (
@@ -93,39 +89,11 @@ class SimpliSafeAlarm(AlarmControlPanel):
             return FORMAT_NUMBER
         return FORMAT_TEXT
 
-    @property
-    def device_info(self):
-        """Return device registry information for this entity."""
-        return {
-            "identifiers": {(DOMAIN, self._system.system_id)},
-            "manufacturer": "SimpliSafe",
-            "model": self._system.version,
-            # The name should become more dynamic once we deduce a way to
-            # get various other sensors from SimpliSafe in a reliable manner:
-            "name": "Keypad",
-            "via_device": (DOMAIN, self._system.serial),
-        }
-
-    @property
-    def device_state_attributes(self):
-        """Return the state attributes."""
-        return self._attrs
-
-    @property
-    def name(self):
-        """Return the name of the entity."""
-        return self._system.address
-
     @property
     def state(self):
         """Return the state of the entity."""
         return self._state
 
-    @property
-    def unique_id(self):
-        """Return the unique ID of the entity."""
-        return self._system.system_id
-
     def _validate_code(self, code, state):
         """Validate given code."""
         check = self._code is None or code == self._code
@@ -133,18 +101,6 @@ class SimpliSafeAlarm(AlarmControlPanel):
             _LOGGER.warning("Wrong code entered for %s", state)
         return check
 
-    async def async_added_to_hass(self):
-        """Register callbacks."""
-
-        @callback
-        def update():
-            """Update the state."""
-            self.async_schedule_update_ha_state(True)
-
-        self._async_unsub_dispatcher_connect = async_dispatcher_connect(
-            self.hass, TOPIC_UPDATE, update
-        )
-
     async def async_alarm_disarm(self, code=None):
         """Send disarm command."""
         if not self._validate_code(code, "disarming"):
@@ -174,6 +130,7 @@ class SimpliSafeAlarm(AlarmControlPanel):
             self._changed_by = event_data["pinName"]
 
         if self._system.state == SystemStates.error:
+            self._online = False
             return
 
         if self._system.state == SystemStates.off:
@@ -195,15 +152,10 @@ class SimpliSafeAlarm(AlarmControlPanel):
                 ATTR_ALARM_ACTIVE: self._system.alarm_going_off,
                 ATTR_LAST_EVENT_INFO: last_event["info"],
                 ATTR_LAST_EVENT_SENSOR_NAME: last_event["sensorName"],
-                ATTR_LAST_EVENT_SENSOR_TYPE: SensorTypes(last_event["sensorType"]).name,
+                ATTR_LAST_EVENT_SENSOR_TYPE: EntityTypes(last_event["sensorType"]).name,
                 ATTR_LAST_EVENT_TIMESTAMP: utc_from_timestamp(
                     last_event["eventTimestamp"]
                 ),
                 ATTR_LAST_EVENT_TYPE: last_event["eventType"],
             }
         )
-
-    async def async_will_remove_from_hass(self) -> None:
-        """Disconnect dispatcher listener when removed."""
-        if self._async_unsub_dispatcher_connect:
-            self._async_unsub_dispatcher_connect()
diff --git a/homeassistant/components/simplisafe/manifest.json b/homeassistant/components/simplisafe/manifest.json
index 96b337def55..254e947ed25 100644
--- a/homeassistant/components/simplisafe/manifest.json
+++ b/homeassistant/components/simplisafe/manifest.json
@@ -4,7 +4,7 @@
   "config_flow": true,
   "documentation": "https://www.home-assistant.io/integrations/simplisafe",
   "requirements": [
-    "simplisafe-python==5.0.1"
+    "simplisafe-python==5.1.0"
   ],
   "dependencies": [],
   "codeowners": [
diff --git a/requirements_all.txt b/requirements_all.txt
index 6f0b40230ed..ccf732ce2ae 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -1769,7 +1769,7 @@ shodan==1.19.0
 simplepush==1.1.4
 
 # homeassistant.components.simplisafe
-simplisafe-python==5.0.1
+simplisafe-python==5.1.0
 
 # homeassistant.components.sisyphus
 sisyphus-control==2.2.1
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 691e8d413d5..99b9c744041 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -546,7 +546,7 @@ rxv==0.6.0
 samsungctl[websocket]==0.7.1
 
 # homeassistant.components.simplisafe
-simplisafe-python==5.0.1
+simplisafe-python==5.1.0
 
 # homeassistant.components.sleepiq
 sleepyq==0.7