diff --git a/cara/tests/apps/calculator/test_model_generator.py b/cara/tests/apps/calculator/test_model_generator.py
index 040ed5df..56ca44ed 100644
--- a/cara/tests/apps/calculator/test_model_generator.py
+++ b/cara/tests/apps/calculator/test_model_generator.py
@@ -85,7 +85,7 @@ def test_ventilation_window_hepa(baseline_form):
     ventilation = models.MultipleVentilation((window,hepa))
 
     baseline_form.ventilation_type = 'natural'
-    baseline_form.windows_open = '10 min / 2h'
+    baseline_form.windows_open = 'interval'
     baseline_form.event_type = 'recurrent_event'
     baseline_form.recurrent_event_month = 'December'
     baseline_form.window_height = 1.6