diff --git a/homeassistant/components/landisgyr_heat_meter/sensor.py b/homeassistant/components/landisgyr_heat_meter/sensor.py
index af966297421..244515a07d4 100644
--- a/homeassistant/components/landisgyr_heat_meter/sensor.py
+++ b/homeassistant/components/landisgyr_heat_meter/sensor.py
@@ -77,6 +77,7 @@ HEAT_METER_SENSOR_TYPES = (
         icon="mdi:fire",
         name="Heat previous year GJ",
         native_unit_of_measurement=UnitOfEnergy.GIGA_JOULE,
+        device_class=SensorDeviceClass.ENERGY,
         entity_category=EntityCategory.DIAGNOSTIC,
         value_fn=lambda res: getattr(res, "heat_previous_year_gj", None),
     ),
diff --git a/tests/components/landisgyr_heat_meter/snapshots/test_sensor.ambr b/tests/components/landisgyr_heat_meter/snapshots/test_sensor.ambr
index e149073d9c8..9c62ca3f94b 100644
--- a/tests/components/landisgyr_heat_meter/snapshots/test_sensor.ambr
+++ b/tests/components/landisgyr_heat_meter/snapshots/test_sensor.ambr
@@ -31,6 +31,7 @@
     }),
     StateSnapshot({
       'attributes': ReadOnlyDict({
+        'device_class': 'energy',
         'friendly_name': 'Heat Meter Heat previous year GJ',
         'icon': 'mdi:fire',
         'unit_of_measurement': <UnitOfEnergy.GIGA_JOULE: 'GJ'>,