diff --git a/flexmeasures/api/v3_0/sensors.py b/flexmeasures/api/v3_0/sensors.py
index e7c91dd99..2aaa76609 100644
--- a/flexmeasures/api/v3_0/sensors.py
+++ b/flexmeasures/api/v3_0/sensors.py
@@ -707,10 +707,10 @@ def get_schedule(  # noqa: C901
         )
 
         sign = 1
-        if sensor.get_attribute("consumption_is_positive", True):
+        if 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:
             return unknown_schedule(
diff --git a/flexmeasures/data/services/scheduling.py b/flexmeasures/data/services/scheduling.py
index 5dfc59d8a..7ea340805 100644
--- a/flexmeasures/data/services/scheduling.py
+++ b/flexmeasures/data/services/scheduling.py
@@ -358,8 +358,8 @@ def make_schedule(
 
         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