diff --git a/caimira/apps/calculator/defaults.py b/caimira/apps/calculator/defaults.py
index 08318c7f..c230e4a9 100644
--- a/caimira/apps/calculator/defaults.py
+++ b/caimira/apps/calculator/defaults.py
@@ -23,7 +23,8 @@ DEFAULTS = {
     'conditional_probability_plot': False,
     'conditional_probability_viral_loads': False,
     'CO2_data': '{}',
-    'CO2_data_option': '{}',
+    'CO2_data_option': False,
+    'CO2_fitting_result': '{}',
     'exposed_coffee_break_option': 'coffee_break_0',
     'exposed_coffee_duration': 5,
     'exposed_finish': '17:30',
diff --git a/caimira/apps/templates/base/calculator.form.html.j2 b/caimira/apps/templates/base/calculator.form.html.j2
index 3b5cb371..a11dfb2a 100644
--- a/caimira/apps/templates/base/calculator.form.html.j2
+++ b/caimira/apps/templates/base/calculator.form.html.j2
@@ -14,6 +14,7 @@
     <script src="{{ get_calculator_url('/static/js') }}/form.js"></script>
     <script src="{{ get_calculator_url('/static/js') }}/co2_form.js"></script>
     <script src="https://cdn.jsdelivr.net/npm/select2@4.1.0-rc.0/dist/js/select2.min.js"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.16.2/xlsx.full.min.js"></script>
 {% endblock body_scripts %}