diff --git a/homeassistant/components/wiffi/__init__.py b/homeassistant/components/wiffi/__init__.py
index 55b13921c1c..e155a48fd72 100644
--- a/homeassistant/components/wiffi/__init__.py
+++ b/homeassistant/components/wiffi/__init__.py
@@ -222,3 +222,11 @@ class WiffiEntity(Entity):
         ):
             self._value = None
             self.async_write_ha_state()
+
+    def _is_measurement_entity(self):
+        """Measurement entities have a value in present time."""
+        return not self._name.endswith("_gestern") and not self._is_metered_entity()
+
+    def _is_metered_entity(self):
+        """Metered entities have a value that keeps increasing until reset."""
+        return self._name.endswith("_pro_h") or self._name.endswith("_heute")
diff --git a/homeassistant/components/wiffi/sensor.py b/homeassistant/components/wiffi/sensor.py
index b9bcd317b46..c16ae3c6aca 100644
--- a/homeassistant/components/wiffi/sensor.py
+++ b/homeassistant/components/wiffi/sensor.py
@@ -5,6 +5,8 @@ from homeassistant.components.sensor import (
     DEVICE_CLASS_ILLUMINANCE,
     DEVICE_CLASS_PRESSURE,
     DEVICE_CLASS_TEMPERATURE,
+    STATE_CLASS_MEASUREMENT,
+    STATE_CLASS_TOTAL_INCREASING,
     SensorEntity,
 )
 from homeassistant.const import DEGREE, PRESSURE_MBAR, TEMP_CELSIUS
@@ -70,6 +72,12 @@ class NumberEntity(WiffiEntity, SensorEntity):
             metric.unit_of_measurement, metric.unit_of_measurement
         )
         self._value = metric.value
+
+        if self._is_measurement_entity():
+            self._attr_state_class = STATE_CLASS_MEASUREMENT
+        elif self._is_metered_entity():
+            self._attr_state_class = STATE_CLASS_TOTAL_INCREASING
+
         self.reset_expiration_date()
 
     @property
@@ -97,7 +105,9 @@ class NumberEntity(WiffiEntity, SensorEntity):
         self._unit_of_measurement = UOM_MAP.get(
             metric.unit_of_measurement, metric.unit_of_measurement
         )
+
         self._value = metric.value
+
         self.async_write_ha_state()