diff --git a/homeassistant/components/plugwise/__init__.py b/homeassistant/components/plugwise/__init__.py
index 8c140f65af9..0e55c3e715c 100644
--- a/homeassistant/components/plugwise/__init__.py
+++ b/homeassistant/components/plugwise/__init__.py
@@ -94,6 +94,10 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 
     api.get_all_devices()
 
+    if entry.unique_id is None:
+        if api.smile_version[0] != "1.8.0":
+            hass.config_entries.async_update_entry(entry, unique_id=api.smile_hostname)
+
     undo_listener = entry.add_update_listener(_update_listener)
 
     hass.data.setdefault(DOMAIN, {})[entry.entry_id] = {
diff --git a/homeassistant/components/plugwise/config_flow.py b/homeassistant/components/plugwise/config_flow.py
index 20c8a5a216c..689bfb68f22 100644
--- a/homeassistant/components/plugwise/config_flow.py
+++ b/homeassistant/components/plugwise/config_flow.py
@@ -96,6 +96,10 @@ class PlugwiseConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             if self.discovery_info:
                 user_input[CONF_HOST] = self.discovery_info[CONF_HOST]
 
+            for entry in self._async_current_entries():
+                if entry.data.get(CONF_HOST) == user_input[CONF_HOST]:
+                    return self.async_abort(reason="already_configured")
+
             try:
                 api = await validate_input(self.hass, user_input)
 
@@ -107,7 +111,9 @@ class PlugwiseConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
                 _LOGGER.exception("Unexpected exception")
                 errors["base"] = "unknown"
             if not errors:
-                await self.async_set_unique_id(api.gateway_id)
+                await self.async_set_unique_id(
+                    api.smile_hostname or api.gateway_id, raise_on_progress=False
+                )
                 self._abort_if_unique_id_configured()
 
                 return self.async_create_entry(title=api.smile_name, data=user_input)
diff --git a/tests/components/plugwise/conftest.py b/tests/components/plugwise/conftest.py
index 8564b2c0d8c..11e077c8a24 100644
--- a/tests/components/plugwise/conftest.py
+++ b/tests/components/plugwise/conftest.py
@@ -73,6 +73,7 @@ def mock_smile_adam():
         smile_mock.return_value.heater_id = "90986d591dcd426cae3ec3e8111ff730"
         smile_mock.return_value.smile_version = "3.0.15"
         smile_mock.return_value.smile_type = "thermostat"
+        smile_mock.return_value.smile_hostname = "smile98765"
 
         smile_mock.return_value.connect.side_effect = AsyncMock(return_value=True)
         smile_mock.return_value.full_update_device.side_effect = AsyncMock(
@@ -112,6 +113,7 @@ def mock_smile_anna():
         smile_mock.return_value.heater_id = "1cbf783bb11e4a7c8a6843dee3a86927"
         smile_mock.return_value.smile_version = "4.0.15"
         smile_mock.return_value.smile_type = "thermostat"
+        smile_mock.return_value.smile_hostname = "smile98765"
 
         smile_mock.return_value.connect.side_effect = AsyncMock(return_value=True)
         smile_mock.return_value.full_update_device.side_effect = AsyncMock(
@@ -151,6 +153,7 @@ def mock_smile_p1():
         smile_mock.return_value.heater_id = None
         smile_mock.return_value.smile_version = "3.3.9"
         smile_mock.return_value.smile_type = "power"
+        smile_mock.return_value.smile_hostname = "smile98765"
 
         smile_mock.return_value.connect.side_effect = AsyncMock(return_value=True)
         smile_mock.return_value.full_update_device.side_effect = AsyncMock(
diff --git a/tests/components/plugwise/test_config_flow.py b/tests/components/plugwise/test_config_flow.py
index 219ba8aee7f..e0f4993df55 100644
--- a/tests/components/plugwise/test_config_flow.py
+++ b/tests/components/plugwise/test_config_flow.py
@@ -111,6 +111,34 @@ async def test_zeroconf_form(hass):
     assert len(mock_setup.mock_calls) == 1
     assert len(mock_setup_entry.mock_calls) == 1
 
+    result3 = await hass.config_entries.flow.async_init(
+        DOMAIN,
+        context={"source": SOURCE_ZEROCONF},
+        data=TEST_DISCOVERY,
+    )
+    assert result3["type"] == data_entry_flow.RESULT_TYPE_FORM
+    assert result3["errors"] == {}
+
+    with patch(
+        "homeassistant.components.plugwise.config_flow.Smile.connect",
+        return_value=True,
+    ), patch(
+        "homeassistant.components.plugwise.async_setup",
+        return_value=True,
+    ) as mock_setup, patch(
+        "homeassistant.components.plugwise.async_setup_entry",
+        return_value=True,
+    ) as mock_setup_entry:
+        result4 = await hass.config_entries.flow.async_configure(
+            result3["flow_id"],
+            {"password": TEST_PASSWORD},
+        )
+
+    await hass.async_block_till_done()
+
+    assert result4["type"] == "abort"
+    assert result4["reason"] == "already_configured"
+
 
 async def test_form_invalid_auth(hass, mock_smile):
     """Test we handle invalid auth."""