diff --git a/.coveragerc b/.coveragerc
index 2f899999f41..533fd8de18d 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -898,6 +898,7 @@ omit =
     homeassistant/components/opengarage/cover.py
     homeassistant/components/opengarage/entity.py
     homeassistant/components/opengarage/sensor.py
+    homeassistant/components/openhardwaremonitor/sensor.py
     homeassistant/components/openhome/__init__.py
     homeassistant/components/openhome/const.py
     homeassistant/components/openhome/media_player.py
diff --git a/homeassistant/components/openhardwaremonitor/sensor.py b/homeassistant/components/openhardwaremonitor/sensor.py
index 70dbbd38fc8..4206bc72c1d 100644
--- a/homeassistant/components/openhardwaremonitor/sensor.py
+++ b/homeassistant/components/openhardwaremonitor/sensor.py
@@ -79,6 +79,8 @@ class OpenHardwareMonitorDevice(SensorEntity):
     @property
     def native_value(self):
         """Return the state of the device."""
+        if self.value == "-":
+            return None
         return self.value
 
     @property