diff --git a/homeassistant/components/sensor/filter.py b/homeassistant/components/sensor/filter.py
index 8e3cda2b7c3..40b37a40d0f 100644
--- a/homeassistant/components/sensor/filter.py
+++ b/homeassistant/components/sensor/filter.py
@@ -15,8 +15,7 @@ from homeassistant.util import slugify
 from homeassistant.core import callback
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
-    CONF_NAME, CONF_ENTITY_ID, ATTR_UNIT_OF_MEASUREMENT, ATTR_ENTITY_ID,
-    EVENT_HOMEASSISTANT_START)
+    CONF_NAME, CONF_ENTITY_ID, ATTR_UNIT_OF_MEASUREMENT, ATTR_ENTITY_ID)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.event import async_track_state_change