diff --git a/homeassistant/components/flexit_bacnet/climate.py b/homeassistant/components/flexit_bacnet/climate.py
index e641a9d7e4f..84785720fb2 100644
--- a/homeassistant/components/flexit_bacnet/climate.py
+++ b/homeassistant/components/flexit_bacnet/climate.py
@@ -15,6 +15,7 @@ from homeassistant.components.climate import (
     PRESET_HOME,
     ClimateEntity,
     ClimateEntityFeature,
+    HVACAction,
     HVACMode,
 )
 from homeassistant.config_entries import ConfigEntry
@@ -83,6 +84,13 @@ class FlexitClimateEntity(FlexitEntity, ClimateEntity):
         """Refresh unit state."""
         await self.device.update()
 
+    @property
+    def hvac_action(self) -> HVACAction | None:
+        """Return current HVAC action."""
+        if self.device.electric_heater:
+            return HVACAction.HEATING
+        return HVACAction.FAN
+
     @property
     def current_temperature(self) -> float:
         """Return the current temperature."""
diff --git a/tests/components/flexit_bacnet/conftest.py b/tests/components/flexit_bacnet/conftest.py
index 307dbcfdd71..cfcecebd19b 100644
--- a/tests/components/flexit_bacnet/conftest.py
+++ b/tests/components/flexit_bacnet/conftest.py
@@ -60,6 +60,7 @@ def mock_flexit_bacnet() -> Generator[AsyncMock, None, None]:
         flexit_bacnet.heat_exchanger_efficiency = 81
         flexit_bacnet.heat_exchanger_speed = 100
         flexit_bacnet.air_filter_polluted = False
+        flexit_bacnet.air_filter_exchange_interval = 8784
         flexit_bacnet.electric_heater = True
 
         # Mock fan setpoints
diff --git a/tests/components/flexit_bacnet/snapshots/test_climate.ambr b/tests/components/flexit_bacnet/snapshots/test_climate.ambr
index fc1d844e1ba..6d5ef2251b8 100644
--- a/tests/components/flexit_bacnet/snapshots/test_climate.ambr
+++ b/tests/components/flexit_bacnet/snapshots/test_climate.ambr
@@ -4,6 +4,7 @@
     'attributes': ReadOnlyDict({
       'current_temperature': 19.0,
       'friendly_name': 'Device Name',
+      'hvac_action': <HVACAction.HEATING: 'heating'>,
       'hvac_modes': list([
         <HVACMode.OFF: 'off'>,
         <HVACMode.FAN_ONLY: 'fan_only'>,