diff --git a/.strict-typing b/.strict-typing
index 5b0bbd569d7..e764449d1d6 100644
--- a/.strict-typing
+++ b/.strict-typing
@@ -35,6 +35,7 @@ homeassistant.components.dlna_dmr.*
 homeassistant.components.dnsip.*
 homeassistant.components.dsmr.*
 homeassistant.components.dunehd.*
+homeassistant.components.efergy.*
 homeassistant.components.elgato.*
 homeassistant.components.esphome.*
 homeassistant.components.energy.*
diff --git a/homeassistant/components/efergy/config_flow.py b/homeassistant/components/efergy/config_flow.py
index 3fb5fbec4a6..f386b539768 100644
--- a/homeassistant/components/efergy/config_flow.py
+++ b/homeassistant/components/efergy/config_flow.py
@@ -56,7 +56,7 @@ class EfergyFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
             errors=errors,
         )
 
-    async def async_step_import(self, import_config: ConfigType):
+    async def async_step_import(self, import_config: ConfigType) -> FlowResult:
         """Import a config entry from configuration.yaml."""
         for entry in self._async_current_entries():
             if entry.data[CONF_API_KEY] == import_config[CONF_APPTOKEN]:
diff --git a/homeassistant/components/efergy/sensor.py b/homeassistant/components/efergy/sensor.py
index cc12fd8486e..1f0db12f449 100644
--- a/homeassistant/components/efergy/sensor.py
+++ b/homeassistant/components/efergy/sensor.py
@@ -143,7 +143,7 @@ async def async_setup_platform(
     hass: HomeAssistant,
     config: ConfigType,
     add_entities: AddEntitiesCallback,
-    discovery_info: DiscoveryInfoType = None,
+    discovery_info: DiscoveryInfoType | None = None,
 ) -> None:
     """Set up the Efergy sensor from yaml."""
     hass.async_create_task(
@@ -194,8 +194,8 @@ class EfergySensor(EfergyEntity, SensorEntity):
         api: Efergy,
         description: SensorEntityDescription,
         server_unique_id: str,
-        period: str = None,
-        currency: str = None,
+        period: str | None = None,
+        currency: str | None = None,
         sid: str = "",
     ) -> None:
         """Initialize the sensor."""
diff --git a/mypy.ini b/mypy.ini
index 5335cde9be2..a429c04caa8 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -396,6 +396,17 @@ no_implicit_optional = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.efergy.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+no_implicit_optional = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.elgato.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true