diff --git a/flexmeasures/api/v3_0/sensors.py b/flexmeasures/api/v3_0/sensors.py
index e7c9450701..7656db327a 100644
--- a/flexmeasures/api/v3_0/sensors.py
+++ b/flexmeasures/api/v3_0/sensors.py
@@ -1023,12 +1023,12 @@ def get_schedule(  # noqa: C901
         )
 
         sign = 1
-        if sensor.measures_power and sensor.get_attribute(
-            "consumption_is_positive", True
+        if sensor.measures_power and not sensor.get_attribute(
+            "consumption_is_positive", False
         ):
             sign = -1
 
-        # For consumption schedules, positive values denote consumption. For the db, consumption is negative
+        # For consumption schedules, positive values denote consumption. For the db, consumption is negative unless specified explicitly
         consumption_schedule = sign * simplify_index(power_values)["event_value"]
         if consumption_schedule.empty:
             # for not in-built schedulers, we are not sure if they would store time series in the db
diff --git a/flexmeasures/data/services/scheduling.py b/flexmeasures/data/services/scheduling.py
index ae3aea6dd6..50502d04fa 100644
--- a/flexmeasures/data/services/scheduling.py
+++ b/flexmeasures/data/services/scheduling.py
@@ -637,8 +637,8 @@ def make_schedule(  # noqa: C901
 
         sign = 1
 
-        if result["sensor"].measures_power and result["sensor"].get_attribute(
-            "consumption_is_positive", True
+        if result["sensor"].measures_power and not result["sensor"].get_attribute(
+            "consumption_is_positive", False
         ):
             sign = -1