diff --git a/merlion/transform/normalize.py b/merlion/transform/normalize.py
index 115a8c20e..7d1aba5db 100644
--- a/merlion/transform/normalize.py
+++ b/merlion/transform/normalize.py
@@ -200,7 +200,7 @@ def _invert(self, time_series: TimeSeries) -> TimeSeries:
         new_vars = []
         for name, var in time_series.items():
             lmbda = self.lmbda[name]
-            if lmbda > 0:
+            if lmbda != 0:
                 var = (lmbda * var + 1) ** (1 / lmbda)
                 nanvals = var.isna()
                 if nanvals.any():