diff --git a/aircon/aircon.py b/aircon/aircon.py
index 855c825..fe88bd0 100644
--- a/aircon/aircon.py
+++ b/aircon/aircon.py
@@ -157,10 +157,19 @@ def queue_command(self, name: str, value) -> None:
     # Device mode is set using t_control_value
     if issubclass(data_type, enum.Enum):
       data_value = data_type[value]
-    elif data_type is int and type(value) is str and '.' in value:
-      # Round rather than fail if the input is a float.
-      # This is commonly the case for temperatures converted by HA from Celsius.
-      data_value = round(float(value))
+    elif data_type is int:
+      # incoming data may be an int or float; it's likely to be a float for
+      # temperatures converted by HA to/from Celsius.
+      float_val = float(value)
+
+      # Granularity may be 0.5, in which case we round to the nearest 0.5, then apply precision
+      granularity = self._properties.get_granularity(name)
+      precision = self._properties.get_precision(name)
+      float_val = (round(float_val / granularity) * granularity) / precision
+
+      # Update value precision for value to be sent to the A/C
+      # We assume that only int types have a precision value
+      data_value = round(float_val)
     else:
       data_value = data_type(value)
 
@@ -174,11 +183,6 @@ def queue_command(self, name: str, value) -> None:
       data_value = data_value.value
       typed_value = data_type[value]
 
-    # Update value precision for value to be sent to the A/C
-    precision = self._properties.get_precision(name)
-    if precision != 1:
-      data_value = round(data_value / precision)
-
     command = self._build_command(name, data_value)
     # There are (usually) no acks on commands, so also queue an update to the
     # property, to be run once the command is sent.
diff --git a/aircon/properties.py b/aircon/properties.py
index 278fdec..4d49713 100644
--- a/aircon/properties.py
+++ b/aircon/properties.py
@@ -153,8 +153,19 @@ def get_base_type(cls, attr: str):
 
   @classmethod
   def get_precision(cls, attr: str):
+    """Precision affects int values; they will be divided by the precision to get a result that's
+    sent to the device. A typical value is 0.1, which means that the value is multiplied by 10.
+    """
     return cls._get_metadata(attr).get('precision', 1)
 
+  @classmethod
+  def get_granularity(cls, attr: str):
+    """Granularity affects int values.  Any incoming float value v will be rounded to the nearest
+    granularity g by round(v/g) * g.  A typical value is 0.5.  Combined with precision of 0.1, this
+    can convert an incoming value of 20.1 to 200, or 20.4 to 205.
+    """
+    return cls._get_metadata(attr).get('granularity', 1)
+
   @classmethod
   def get_read_only(cls, attr: str):
     return cls._get_metadata(attr)['read_only']
@@ -404,6 +415,7 @@ class FglProperties(Properties):
                                   metadata={
                                       'base_type': 'integer',
                                       'precision': 0.1,
+                                      'granularity': 0.5,
                                       'read_only': False
                                   })
   af_vertical_direction: int = field(default=3,