diff --git a/caimira/apps/calculator/static/js/co2_form.js b/caimira/apps/calculator/static/js/co2_form.js
index 09e7c8c8..b48c5d90 100644
--- a/caimira/apps/calculator/static/js/co2_form.js
+++ b/caimira/apps/calculator/static/js/co2_form.js
@@ -147,11 +147,10 @@ function submit_fitting_algorithm(url) {
 		})
 			.then((response) => response.json())
 			.then((json_response) => {
-				console.log(json_response)
 				$("#DIV_CO2_fitting_result").show();
 				$("#CO2_fitting_result").val(JSON.stringify(json_response));
-				$("#exhalation_rate_fit").html(String(json_response['exhalation_rate']));
-				$("#ventilation_rate_fit").html(json_response['ventilation_values']);
+				$("#exhalation_rate_fit").html('Exhalation rate: ' + String(json_response['exhalation_rate'].toFixed(2)) + ' m³/h');
+				// $("#ventilation_rate_fit").html(json_response['ventilation_values']);
 				$("#CO2_data_plot").attr("src", json_response['CO2_plot']);
 				$("#generate_fitting_data").html('Fit data');
 				$("#save_and_dismiss_dialog").show();
diff --git a/caimira/apps/calculator/static/js/form.js b/caimira/apps/calculator/static/js/form.js
index 81623bc8..63ac8673 100644
--- a/caimira/apps/calculator/static/js/form.js
+++ b/caimira/apps/calculator/static/js/form.js
@@ -521,8 +521,8 @@ function on_CO2_data_option_change() {
   CO2_data_options = $('input[type=radio][name=CO2_data_option]');
   CO2_data_options.each(function (index){
     if (this.checked) {
-      // if (this.id == 'CO2_data_yes') ventilation_from_fitting(true);
-      // else if (this.id == 'CO2_data_no') ventilation_from_fitting(false);
+      if (this.id == 'CO2_data_yes') ventilation_from_fitting(true);
+      else if (this.id == 'CO2_data_no') ventilation_from_fitting(false);
       getChildElement($(this)).show();
       require_fields(this);
     } 
@@ -713,6 +713,8 @@ function validate_form(form) {
     );
   }
 
+  if ($("#CO2_fitting_result").val() == "") $("#CO2_data_no").click();
+
   return submit;
 }
 
diff --git a/caimira/apps/templates/base/calculator.form.html.j2 b/caimira/apps/templates/base/calculator.form.html.j2
index 4b47b334..47d3368c 100644
--- a/caimira/apps/templates/base/calculator.form.html.j2
+++ b/caimira/apps/templates/base/calculator.form.html.j2
@@ -671,13 +671,28 @@
         <div>
           <input class="ml-2" type="radio" id="CO2_data_no" name="CO2_data_option" value=0 checked="checked">
             <label for="CO2_data_no">No</label>
-          <input class="ml-2" type="radio" id="CO2_data_yes" name="CO2_data_option" value=1 data-target="#DIVCO2_data" data-toggle="modal">
+          <input class="ml-2" type="radio" id="CO2_data_yes" name="CO2_data_option" value=1 data-enables="#DIVCO2_data">
             <label for="CO2_data_yes">Yes</label>
         </div>
     </div>
 
+    <div id="DIVCO2_data" class="split" style="display: none">
+      <div>
+        For the CO₂ fitting algorithm, the following input values will be considered:
+        <ul>
+          <li>Room volume (m³)</li>
+          <li>Ventilation transition times</li>
+          <li>Total number of occupants</li>
+          <li>Presence transition times</li>
+        </ul>
+      </div>
+      <div class="align-self-center text-center">
+        <button type="button" class="btn btn-primary" style="width: 60%" data-toggle="modal" data-target="#DIVCO2_data_dialog" data-keyboard="false" data-backdrop="static">Fit Data</button>
+      </div>
+    </div>
+
     <!-- CO2 Modal -->
-    <div class="modal fade" id="DIVCO2_data" tabindex="-1" role="dialog" aria-labelledby="CO2_values_title" aria-hidden="true" data-backdrop="static">
+    <div class="modal fade" id="DIVCO2_data_dialog" tabindex="-1" role="dialog" aria-labelledby="CO2_values_title" aria-hidden="true" data-backdrop="static">
       <div class="modal-dialog modal-lg" role="document" overflow: visible>
         <div class="modal-content">
           <div class="modal-header">
@@ -701,24 +716,25 @@
             <table id="display_excel_data" border="1" style="width: 70%; margin-left: auto; margin-right: auto"></table>
             <input id="formatted_data" type="text" name="CO2_data" class="form-control form-control-sm d-none" placeholder='{"times": [...], "concentrations": [...]}' ><br>
             <div id="CO2_input_data_div" style="display: none">
-              <p>The following data will be considered:</p><br>
-              <p id="CO2_input_data"></p>
+              {# <p>The following data will be considered:</p><br>
+              <p id="CO2_input_data"></p> #}
             </div>
             <input type="text" class="form-control d-none" name="CO2_fitting_result" id="CO2_fitting_result">
             <div id="DIV_CO2_fitting_result" style="display: none">
-              <img id="CO2_data_plot"/>
-              <div>Exhalation rate: <p id="exhalation_rate_fit"></p> </div>
-              <div>Air exchange: <p id="ventilation_rate_fit"></p></div>
+              <h5 style="margin-top: auto; margin-bottom: auto">Fitting result</h5>
+              <img id="CO2_data_plot" style="margin-top: 2%"/>
+              <p id="exhalation_rate_fit"></p>
+              <p id="ventilation_rate_fit">Ventilation values in the plot (ACH)</p>
             </div>
           </div>
           <div class="modal-footer">
-            <button type="button" class="btn btn-secondary dismiss_btn_frm_field" data-dismiss="modal" onclick="clear_fitting_algorithm()">Clear all</button>
+            <button type="button" class="btn btn-secondary dismiss_btn_frm_field" data-dismiss="modal" onclick="clear_fitting_algorithm()">Clear all/Discard</button>
             <button type="button" id="generate_fitting_data" class="btn btn-primary close_btn_frm_field" onclick="submit_fitting_algorithm('{{ get_calculator_url() }}/co2-fit')" disabled>Fit data</button>
             <button type="button" style="display: none" id="save_and_dismiss_dialog" class="btn btn-primary close_btn_frm_field" data-dismiss="modal">Save and close</button>
           </div>
         </div>
       </div>
-    </div>
+    </div> 
   
   </div> 
   </div>