diff --git a/homeassistant/components/nut/const.py b/homeassistant/components/nut/const.py
index 64dc95d7b95..a8591349b56 100644
--- a/homeassistant/components/nut/const.py
+++ b/homeassistant/components/nut/const.py
@@ -90,7 +90,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.delay.start",
         name="Load Restart Delay",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -98,7 +98,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.delay.reboot",
         name="UPS Reboot Delay",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -106,7 +106,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.delay.shutdown",
         name="UPS Shutdown Delay",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -114,7 +114,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.timer.start",
         name="Load Start Timer",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -122,7 +122,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.timer.reboot",
         name="Load Reboot Timer",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -130,7 +130,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.timer.shutdown",
         name="Load Shutdown Timer",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -138,7 +138,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="ups.test.interval",
         name="Self-Test Interval",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -369,7 +369,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="battery.runtime",
         name="Battery Runtime",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -377,7 +377,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="battery.runtime.low",
         name="Low Battery Runtime",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),
@@ -385,7 +385,7 @@ SENSOR_TYPES: Final[dict[str, SensorEntityDescription]] = {
         key="battery.runtime.restart",
         name="Minimum Battery Runtime to Start",
         native_unit_of_measurement=TIME_SECONDS,
-        icon="mdi:timer-outline",
+        device_class=SensorDeviceClass.DURATION,
         entity_category=EntityCategory.DIAGNOSTIC,
         entity_registry_enabled_default=False,
     ),