1 files changed, 1 insertions, 1 deletions
diff --git a/model.py b/model.py
index fc43ad7..cf8c593 100644
--- a/model.py
+++ b/model.py
@@ -105,7 +105,7 @@ class MonthExpense (namedtuple('MonthExpense', 'date catexps')):
     @property
     def constsum (self):
         c = ConstExpense.of_month(self.date.month, self.date.year)
-        return c.value(sql.functions.sum(ConstExpense.monthly)) or None
+        return c.value(sql.functions.sum(ConstExpense.monthly)) or 0
 
     @property
     def consts (self):