diff --git a/homeassistant/components/whois/sensor.py b/homeassistant/components/whois/sensor.py
index 5d5e595fa50..3742ed90131 100644
--- a/homeassistant/components/whois/sensor.py
+++ b/homeassistant/components/whois/sensor.py
@@ -49,45 +49,19 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
 class WhoisSensor(SensorEntity):
     """Implementation of a WHOIS sensor."""
 
+    _attr_icon = "mdi:calendar-clock"
+    _attr_native_unit_of_measurement = TIME_DAYS
+
     def __init__(self, name, domain):
         """Initialize the sensor."""
         self.whois = whois.whois
-
-        self._name = name
         self._domain = domain
+        self._attr_name = name
 
-        self._state = None
-        self._attributes = None
-
-    @property
-    def name(self):
-        """Return the name of the sensor."""
-        return self._name
-
-    @property
-    def icon(self):
-        """Return the icon to represent this sensor."""
-        return "mdi:calendar-clock"
-
-    @property
-    def native_unit_of_measurement(self):
-        """Return the unit of measurement to present the value in."""
-        return TIME_DAYS
-
-    @property
-    def native_value(self):
-        """Return the expiration days for hostname."""
-        return self._state
-
-    @property
-    def extra_state_attributes(self):
-        """Get the more info attributes."""
-        return self._attributes
-
-    def _empty_state_and_attributes(self):
+    def _empty_value_and_attributes(self):
         """Empty the state and attributes on an error."""
-        self._state = None
-        self._attributes = None
+        self._attr_native_value = None
+        self._attr_extra_state_attributes = None
 
     def update(self):
         """Get the current WHOIS data for the domain."""
@@ -95,7 +69,7 @@ class WhoisSensor(SensorEntity):
             response = self.whois(self._domain)
         except whois.BaseException as ex:  # pylint: disable=broad-except
             _LOGGER.error("Exception %s occurred during WHOIS lookup", ex)
-            self._empty_state_and_attributes()
+            self._empty_value_and_attributes()
             return
 
         if response:
@@ -105,12 +79,12 @@ class WhoisSensor(SensorEntity):
                     "Did find: %s",
                     ", ".join(response.keys()),
                 )
-                self._empty_state_and_attributes()
+                self._empty_value_and_attributes()
                 return
 
             if not response["expiration_date"]:
                 _LOGGER.error("Whois response contains empty expiration_date")
-                self._empty_state_and_attributes()
+                self._empty_value_and_attributes()
                 return
 
             attrs = {}
@@ -137,5 +111,5 @@ class WhoisSensor(SensorEntity):
 
             time_delta = expiration_date - expiration_date.now()
 
-            self._attributes = attrs
-            self._state = time_delta.days
+            self._attr_extra_state_attributes = attrs
+            self._attr_native_value = time_delta.days