diff --git a/ramp/core/core.py b/ramp/core/core.py
index 8637eb6..d1833d4 100644
--- a/ramp/core/core.py
+++ b/ramp/core/core.py
@@ -1184,7 +1184,7 @@ def __init__(
         self.random_var_1 = 0
         self.random_var_2 = 0
         self.random_var_3 = 0
-        self.daily_use = None
+        self.daily_use = np.zeros(1440)
         self.free_spots = None
 
         # attributes used for specific fixed and random cycles