diff --git a/cara/apps/calculator/model_generator.py b/cara/apps/calculator/model_generator.py
index 1974e6df..88d0dcb6 100644
--- a/cara/apps/calculator/model_generator.py
+++ b/cara/apps/calculator/model_generator.py
@@ -43,6 +43,8 @@ class FormData:
     total_people: int
     ventilation_type: str
     volume_type: str
+    windows_duration: float
+    windows_frequency: float
     window_height: float
     window_type: str
     window_width: float
@@ -121,6 +123,8 @@ class FormData:
             total_people=int(form_data['total_people']),
             ventilation_type=form_data['ventilation_type'],
             volume_type=form_data['volume_type'],
+            windows_duration=float(form_data['windows_duration']),
+            windows_frequency=float(form_data['windows_frequency']),
             window_height=float(form_data['window_height']),
             window_type=form_data['window_type'],
             window_width=float(form_data['window_width']),
@@ -138,7 +142,7 @@ class FormData:
         # Initializes a ventilation instance as a window if 'natural' is selected, or as a HEPA-filter otherwise
         if self.ventilation_type == 'natural':
             if self.windows_open == 'interval':
-                window_interval = models.PeriodicInterval(120, 10)
+                window_interval = models.PeriodicInterval(self.windows_frequency*60, self.windows_duration)
             else:
                 window_interval = always_on
 
@@ -424,7 +428,7 @@ def baseline_raw_form_data():
         'mask_type': 'Type I',
         'mask_wearing': 'removed',
         'mechanical_ventilation_type': '',
-        'model_version': 'v1.1.0',
+        'model_version': 'v1.2.0',
         'opening_distance': '0.2',
         'recurrent_event_month': 'January',
         'room_number': '123',
@@ -438,7 +442,7 @@ def baseline_raw_form_data():
         'window_type': 'sliding',
         'window_width': '2',
         'windows_number': '1',
-        'windows_open': 'interval'
+        'windows_open': 'always'
     }
 
 
@@ -449,7 +453,7 @@ MASK_TYPES = {'Type I', 'FFP2'}
 MASK_WEARING = {'continuous', 'removed'}
 VENTILATION_TYPES = {'natural', 'mechanical', 'no-ventilation'}
 VOLUME_TYPES = {'room_volume', 'room_dimensions'}
-WINDOWS_OPEN = {'always', 'interval', 'breaks', 'not-applicable'}
+WINDOWS_OPEN = {'always', 'interval', 'not-applicable'}
 WINDOWS_TYPES = {'sliding', 'hinged', 'not-applicable'}
 
 
diff --git a/cara/apps/calculator/templates/report.html.j2 b/cara/apps/calculator/templates/report.html.j2
index ded74dbb..c640d0f9 100644
--- a/cara/apps/calculator/templates/report.html.j2
+++ b/cara/apps/calculator/templates/report.html.j2
@@ -33,7 +33,7 @@
 	<p class="data_title">Ventilation data:</p>
 	<ul>
 		<li><p class="data_text">Mechanical ventilation:
-		{% if form.ventilation_type == "mechanical"%}
+		{% if form.ventilation_type == "mechanical" %}
 		Yes </p></li>
 		<ul>
 			<li><p class="data_subtext">
@@ -61,7 +61,13 @@
 			Sliding / Side-Hung</p></li>
 			{% endif %}
 			<li><p class="data_subtext">Opening distance: {{ form.opening_distance }} m</p></li>
-			<li><p class="data_subtext">Windows open: {{ form.windows_open }}</p></li>
+			<li><p class="data_subtext">Windows open: 
+			{% if form.windows_open == "interval" %}
+			{{ form.windows_open }}s of {{ form.windows_duration }} mins every {{ form.windows_frequency }} hours
+			{% else %}
+			{{ form.windows_open }}
+			{% endif %}
+			</p></li>
 		</ul>
 			<p class="data_subtext data_italic">When using the natural ventilation option, air flows are calculated using averaged hourly temperatures for the Geneva region, based on historical data for the month selected.</p>
 		{% else %}
@@ -90,7 +96,7 @@
 		Call Centre = typical office-like scenario with all persons seated, all talking continuously.
 		{% elif form.activity_type == "library" %}
 		Library = Library scenario with all persons seated, breathing and not talking.
-    {% elif form.activity_type == "workshop" %}
+    	{% elif form.activity_type == "workshop" %}
 		Workshop = assembly workshop environment, all persons doing moderate physical activity, talking 50% of the time.
 		{% elif form.activity_type == "training" %}
 		Training – one person (the trainer) standing, talking, all others seated, talking quietly (whispering). It is assumed the trainer is the infected person, for the worst case scenario.