diff --git a/homeassistant/components/demo/climate.py b/homeassistant/components/demo/climate.py
index 0eaa7d5f41f..b857f98e2da 100644
--- a/homeassistant/components/demo/climate.py
+++ b/homeassistant/components/demo/climate.py
@@ -56,10 +56,10 @@ async def async_setup_entry(
                 unit_of_measurement=UnitOfTemperature.CELSIUS,
                 preset=None,
                 current_temperature=22,
-                fan_mode="On High",
+                fan_mode="on_high",
                 target_humidity=67,
                 current_humidity=54,
-                swing_mode="Off",
+                swing_mode="off",
                 hvac_mode=HVACMode.COOL,
                 hvac_action=HVACAction.COOLING,
                 aux=False,
@@ -75,10 +75,10 @@ async def async_setup_entry(
                 preset="home",
                 preset_modes=["home", "eco", "away"],
                 current_temperature=23,
-                fan_mode="Auto Low",
+                fan_mode="auto_low",
                 target_humidity=None,
                 current_humidity=None,
-                swing_mode="Auto",
+                swing_mode="auto",
                 hvac_mode=HVACMode.HEAT_COOL,
                 hvac_action=None,
                 aux=None,
diff --git a/tests/components/demo/test_climate.py b/tests/components/demo/test_climate.py
index 97b436ea2b0..18992c0d0f4 100644
--- a/tests/components/demo/test_climate.py
+++ b/tests/components/demo/test_climate.py
@@ -76,10 +76,10 @@ def test_setup_params(hass: HomeAssistant) -> None:
     assert state.state == HVACMode.COOL
     assert state.attributes.get(ATTR_TEMPERATURE) == 21
     assert state.attributes.get(ATTR_CURRENT_TEMPERATURE) == 22
-    assert state.attributes.get(ATTR_FAN_MODE) == "On High"
+    assert state.attributes.get(ATTR_FAN_MODE) == "on_high"
     assert state.attributes.get(ATTR_HUMIDITY) == 67
     assert state.attributes.get(ATTR_CURRENT_HUMIDITY) == 54
-    assert state.attributes.get(ATTR_SWING_MODE) == "Off"
+    assert state.attributes.get(ATTR_SWING_MODE) == "off"
     assert state.attributes.get(ATTR_AUX_HEAT) == STATE_OFF
     assert state.attributes.get(ATTR_HVAC_MODES) == [
         HVACMode.OFF,
@@ -256,7 +256,7 @@ async def test_set_target_humidity(hass: HomeAssistant) -> None:
 async def test_set_fan_mode_bad_attr(hass: HomeAssistant) -> None:
     """Test setting fan mode without required attribute."""
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_FAN_MODE) == "On High"
+    assert state.attributes.get(ATTR_FAN_MODE) == "on_high"
 
     with pytest.raises(vol.Invalid):
         await hass.services.async_call(
@@ -267,13 +267,13 @@ async def test_set_fan_mode_bad_attr(hass: HomeAssistant) -> None:
         )
 
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_FAN_MODE) == "On High"
+    assert state.attributes.get(ATTR_FAN_MODE) == "on_high"
 
 
 async def test_set_fan_mode(hass: HomeAssistant) -> None:
     """Test setting of new fan mode."""
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_FAN_MODE) == "On High"
+    assert state.attributes.get(ATTR_FAN_MODE) == "on_high"
 
     await hass.services.async_call(
         DOMAIN,
@@ -289,7 +289,7 @@ async def test_set_fan_mode(hass: HomeAssistant) -> None:
 async def test_set_swing_mode_bad_attr(hass: HomeAssistant) -> None:
     """Test setting swing mode without required attribute."""
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_SWING_MODE) == "Off"
+    assert state.attributes.get(ATTR_SWING_MODE) == "off"
 
     with pytest.raises(vol.Invalid):
         await hass.services.async_call(
@@ -300,13 +300,13 @@ async def test_set_swing_mode_bad_attr(hass: HomeAssistant) -> None:
         )
 
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_SWING_MODE) == "Off"
+    assert state.attributes.get(ATTR_SWING_MODE) == "off"
 
 
 async def test_set_swing(hass: HomeAssistant) -> None:
     """Test setting of new swing mode."""
     state = hass.states.get(ENTITY_CLIMATE)
-    assert state.attributes.get(ATTR_SWING_MODE) == "Off"
+    assert state.attributes.get(ATTR_SWING_MODE) == "off"
 
     await hass.services.async_call(
         DOMAIN,
diff --git a/tests/components/google_assistant/test_google_assistant.py b/tests/components/google_assistant/test_google_assistant.py
index 177220cc02f..6d3a9b34cce 100644
--- a/tests/components/google_assistant/test_google_assistant.py
+++ b/tests/components/google_assistant/test_google_assistant.py
@@ -243,7 +243,7 @@ async def test_query_climate_request(
         "thermostatTemperatureAmbient": 23,
         "thermostatMode": "heatcool",
         "thermostatTemperatureSetpointLow": 21,
-        "currentFanSpeedSetting": "Auto Low",
+        "currentFanSpeedSetting": "auto_low",
     }
     assert devices["climate.hvac"] == {
         "online": True,
@@ -251,7 +251,7 @@ async def test_query_climate_request(
         "thermostatTemperatureAmbient": 22,
         "thermostatMode": "cool",
         "thermostatHumidityAmbient": 54,
-        "currentFanSpeedSetting": "On High",
+        "currentFanSpeedSetting": "on_high",
     }
 
 
@@ -304,7 +304,7 @@ async def test_query_climate_request_f(
         "thermostatTemperatureAmbient": -5,
         "thermostatMode": "heatcool",
         "thermostatTemperatureSetpointLow": -6.1,
-        "currentFanSpeedSetting": "Auto Low",
+        "currentFanSpeedSetting": "auto_low",
     }
     assert devices["climate.hvac"] == {
         "online": True,
@@ -312,7 +312,7 @@ async def test_query_climate_request_f(
         "thermostatTemperatureAmbient": -5.6,
         "thermostatMode": "cool",
         "thermostatHumidityAmbient": 54,
-        "currentFanSpeedSetting": "On High",
+        "currentFanSpeedSetting": "on_high",
     }
     hass_fixture.config.units.temperature_unit = UnitOfTemperature.CELSIUS