diff --git a/homeassistant/components/statistics/sensor.py b/homeassistant/components/statistics/sensor.py
index ac62b63e8ca..3f33fa015b9 100644
--- a/homeassistant/components/statistics/sensor.py
+++ b/homeassistant/components/statistics/sensor.py
@@ -350,7 +350,7 @@ class StatisticsSensor(SensorEntity):
         if new_state.state == STATE_UNAVAILABLE:
             self.attributes[STAT_SOURCE_VALUE_VALID] = None
             return
-        if new_state.state in (STATE_UNKNOWN, None):
+        if new_state.state in (STATE_UNKNOWN, None, ""):
             self.attributes[STAT_SOURCE_VALUE_VALID] = False
             return