diff --git a/scripts/perturbation.py b/scripts/perturbation.py
index 225fcc1d..cefb89b2 100644
--- a/scripts/perturbation.py
+++ b/scripts/perturbation.py
@@ -1,14 +1,15 @@
 #!/usr/bin/env python2
 
 import os
+from qp_path import QP_SRC
 
-Pert_dir = os.environ["QP_ROOT"]+"/src/perturbation/"
+Pert_dir = os.path.join(QP_SRC,"perturbation")
 
 perturbations = []
 
 for filename in filter(lambda x: x.endswith(".irp.f"), os.listdir(Pert_dir)):
 
-  filename = Pert_dir+filename
+  filename = os.path.join(Pert_dir,filename)
   file = open(filename,'r')
   lines = file.readlines()
   file.close()