diff --git a/mlair/data_handler/abstract_data_handler.py b/mlair/data_handler/abstract_data_handler.py
index 419db059a58beeb4ed7e3e198e41b565f8dc7d25..53d4597060f9452e4a59cfa1001da9aaa86056b8 100644
--- a/mlair/data_handler/abstract_data_handler.py
+++ b/mlair/data_handler/abstract_data_handler.py
@@ -6,6 +6,7 @@ import inspect
 from typing import Union, Dict
 
 from mlair.helpers import remove_items
+import logging
 
 
 class AbstractDataHandler:
@@ -13,6 +14,7 @@ class AbstractDataHandler:
     _requirements = []
 
     def __init__(self, *args, **kwargs):
+        logging.info("Initialise AbstractDataHandler")
         pass
 
     @classmethod
diff --git a/mlair/data_handler/data_handler_single_station.py b/mlair/data_handler/data_handler_single_station.py
index 9fdba43cc2b6b3f9ed7a6d97dbd43ec86f03a1f7..163a0a7754fc34e61383e99c7bc608d13b9f03f6 100644
--- a/mlair/data_handler/data_handler_single_station.py
+++ b/mlair/data_handler/data_handler_single_station.py
@@ -62,6 +62,7 @@ class DataHandlerSingleStation(AbstractDataHandler):
                  overwrite_local_data: bool = False, transformation=None, store_data_locally: bool = True,
                  min_length: int = 0, start=None, end=None, variables=None, data_origin: Dict = None,
                  lazy_preprocessing: bool = False, aggregation_dim=None, **kwargs):
+        logging.info(f"Initialise DataHandlerSingleStation")
         super().__init__()
         self.station = helpers.to_list(station)
         self.path = self.setup_data_path(data_path, sampling)
diff --git a/mlair/data_handler/data_handler_wrf_chem.py b/mlair/data_handler/data_handler_wrf_chem.py
index 839d16522b9edfdb6d085a2860ab031b2800b5ba..69d2cb7fece19d88e0c41af188d0705c237e1a25 100644
--- a/mlair/data_handler/data_handler_wrf_chem.py
+++ b/mlair/data_handler/data_handler_wrf_chem.py
@@ -396,6 +396,7 @@ class DataHandlerSingleGridColumn(DataHandlerSingleStation):
     def __init__(self, *args, external_coords_file=None,
                  var_logical_z_coord_selector=None,
                  targetvar_logical_z_coord_selector=None, **kwargs):
+        logging.info("Initialise DataHandlerSingleGridColumn")
         self.external_coords_file = external_coords_file
         self.var_logical_z_coord_selector = self._ret_z_coord_select_if_valid(var_logical_z_coord_selector,
                                                                               as_input=True)
@@ -607,6 +608,7 @@ class DataHandlerSectorGrid(DataHandlerSingleGridColumn):
     _requirements = DataHandlerWRF.requirements()
 
     def __init__(self, *args, radius=None, sectors=None, wind_sector_edge_dim_name=None,  **kwargs):
+        logging.info("Initialise DataHandlerSectorGrid")
         if radius is None:
             radius = 100  # km
         self.radius = radius
diff --git a/mlair/data_handler/default_data_handler.py b/mlair/data_handler/default_data_handler.py
index 15271c8041decd8a7aad6f053feb61f8343c82b5..5a5e8d14dd70e11b9a7f04f3640a86d8b77122f3 100644
--- a/mlair/data_handler/default_data_handler.py
+++ b/mlair/data_handler/default_data_handler.py
@@ -60,6 +60,7 @@ class DefaultDataHandler(AbstractDataHandler):
 
     @classmethod
     def build(cls, station: str, **kwargs):
+        logging.info(f"build dh: DefaultDataHandler")
         sp_keys = {k: copy.deepcopy(kwargs[k]) for k in cls._requirements if k in kwargs}
         sp = cls.data_handler(station, **sp_keys)
         dp_args = {k: copy.deepcopy(kwargs[k]) for k in cls.own_args("id_class") if k in kwargs}