diff --git a/changelog.md b/changelog.md
index bedf4394..03182bb8 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,7 @@
+# Version 2024.8.9 (2024-08-20)
+
+- Avoid excessive memory usage in cache
+
 # Version 2024.8.8 (2024-08-18)
 
 - Refactor folder handling
diff --git a/hahomematic/caches/persistent.py b/hahomematic/caches/persistent.py
index 9ec3345f..3b479d9d 100644
--- a/hahomematic/caches/persistent.py
+++ b/hahomematic/caches/persistent.py
@@ -286,7 +286,7 @@ def __init__(self, central: hmcu.CentralUnit) -> None:
         )
 
         # {(device_address, parameter), [channel_no]}
-        self._address_parameter_cache: Final[dict[tuple[str, str], list[int]]] = {}
+        self._address_parameter_cache: Final[dict[tuple[str, str], set[int]]] = {}
 
     @property
     def raw_paramset_descriptions(self) -> dict[str, dict[str, dict[str, dict[str, Any]]]]:
@@ -399,10 +399,8 @@ def _init_address_parameter_list(self) -> None:
                             device_address,
                             parameter,
                         ) not in self._address_parameter_cache:
-                            self._address_parameter_cache[(device_address, parameter)] = []
-                        self._address_parameter_cache[(device_address, parameter)].append(
-                            channel_no
-                        )
+                            self._address_parameter_cache[(device_address, parameter)] = set()
+                        self._address_parameter_cache[(device_address, parameter)].add(channel_no)
 
     async def load(self) -> DataOperationResult:
         """Load paramset descriptions from disk into paramset cache."""
diff --git a/pyproject.toml b/pyproject.toml
index 69322159..2bb3282e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name        = "hahomematic"
-version     = "2024.8.8"
+version     = "2024.8.9"
 license     = {text = "MIT License"}
 description = "Homematic interface for Home Assistant running on Python 3."
 readme      = "README.md"