diff --git a/caimira/apps/calculator/static/js/co2_form.js b/caimira/apps/calculator/static/js/co2_form.js
index 59189d37..bf9751bd 100644
--- a/caimira/apps/calculator/static/js/co2_form.js
+++ b/caimira/apps/calculator/static/js/co2_form.js
@@ -1,7 +1,5 @@
-// JS file to handle manipulation on CO2 Fitting Algorithm Dialog.
 const CO2_data_form = [
 	'CO2_data',
-	'specific_breaks',
 	'exposed_coffee_break_option',
 	'exposed_coffee_duration',
 	'exposed_finish',
@@ -9,6 +7,8 @@ const CO2_data_form = [
 	'exposed_lunch_option',
 	'exposed_lunch_start',
 	'exposed_start',
+	'fitting_ventilation_states',
+	'fitting_ventilation_type',
 	'infected_coffee_break_option',
 	'infected_coffee_duration',
 	'infected_dont_have_breaks_with_exposed',
@@ -21,174 +21,239 @@ const CO2_data_form = [
 	'room_volume',
 	'total_people',
 	'ventilation_type',
-	'windows_duration',
-	'windows_frequency',
-	'window_opening_regime',
-]
-
-// Method to upload a valid excel file
-function upload_file() {
-	clear_fitting_result_component();
-	$("#generate_fitting_data").show();
-	$("#save_and_dismiss_dialog").hide();
-	var files = document.getElementById("file_upload").files;
-	if (files.length == 0) {
-		alert("Please choose any file...");
-		return;
+  ];
+  
+  // Method to upload a valid excel file
+  function uploadFile(endpoint) {
+	clearFittingResultComponent();
+	const files = document.getElementById("file_upload").files;
+	if (files.length === 0) {
+	  alert("Please choose any file...");
+	  return;
 	}
-	const filename = files[0].name;
-	const extension = filename.substring(filename.lastIndexOf(".")).toUpperCase();
-	if (extension == ".XLS" || extension == ".XLSX") {
-		//Here calling another method to read excel file into json
-		excelFileToJSON(files[0]);
-	} else {
-		alert("Please select a valid excel file.");
-	}
-}
-
-//Method to read excel file and convert it into JSON
-function excelFileToJSON(file) {
+	const file = files[0];
+	const extension = file.name.substring(file.name.lastIndexOf(".")).toUpperCase();
+	extension === ".XLS" || extension === ".XLSX"
+	  ? excelFileToJSON(endpoint, file)
+	  : alert("Please select a valid excel file.");
+  }
+  
+  // Method to read excel file and convert it into JSON
+  function excelFileToJSON(endpoint, file) {
 	try {
-		var reader = new FileReader();
-		reader.readAsBinaryString(file);
-		reader.onload = function (e) {
-			var data = e.target.result;
-			var workbook = XLSX.read(data, { type: "binary" });
-			var firstSheetName = workbook.SheetNames[0];
-			//reading only first sheet data
-			var jsonData = XLSX.utils.sheet_to_json(workbook.Sheets[firstSheetName]);
-			//displaying the json result into HTML table
-			displayJsonToHtmlTable(jsonData);
-		};
+	  const reader = new FileReader();
+	  reader.readAsBinaryString(file);
+	  reader.onload = function (e) {
+		const data = e.target.result;
+		const workbook = XLSX.read(data, { type: "binary" });
+		const firstSheetName = workbook.SheetNames[0];
+		const jsonData = XLSX.utils.sheet_to_json(workbook.Sheets[firstSheetName]);
+		displayJsonToHtmlTable(endpoint, jsonData);
+	  };
 	} catch (e) {
-		console.error(e);
+	  console.error(e);
 	}
-}
-
-//Method to display the data in HTML Table
-function displayJsonToHtmlTable(jsonData) {
-	var table = document.getElementById("display_excel_data");
-	var format = document.getElementById("formatted_data");
-	let structure = { times: [], CO2: [] };
+  }
+  
+  // Method to display the data in HTML Table
+  function displayJsonToHtmlTable(endpoint, jsonData) {
+	const table = document.getElementById("display_excel_data");
+	const format = document.getElementById("CO2_data");
+	const structure = { times: [], CO2: [] };
 	if (jsonData.length > 0) {
-		var htmlData = "<tr><th>Time</th><th>CO2 Value</th></tr>";
-		let jsonLength = jsonData.length;
-		for (var i = 0; i < jsonLength; i++) {
-			var row = jsonData[i];
-			if (i < 5) {
-				htmlData +=
-					`<tr><td>
-					${row["Times"].toFixed(2)}
-					</td><td>
-					${row["CO2"].toFixed(2)}
-					</td></tr>`;
-			}
-			structure["times"].push(row["Times"]);
-			structure["CO2"].push(row["CO2"]);
+	  let htmlData = "<tr><th>Time</th><th>CO2 Value</th></tr>";
+	  const jsonLength = jsonData.length;
+	  for (let i = 0; i < jsonLength; i++) {
+		const row = jsonData[i];
+		if (i < 5) {
+		  htmlData += `
+			<tr>
+			  <td>${row["Times"].toFixed(2)}</td>
+			  <td>${row["CO2"].toFixed(2)}</td>
+			</tr>`;
 		}
-
-		if (jsonLength >= 5) htmlData += "<tr><td> ... </td><td> ... </td></tr>";
-		table.innerHTML = htmlData;
-		format.value = JSON.stringify(structure);
-		$('#generate_fitting_data').prop("disabled", false);
+		structure.times.push(row["Times"]);
+		structure.CO2.push(row["CO2"]);
+	  }
+  
+	  if (jsonLength >= 5) {
+		htmlData += "<tr><td> ... </td><td> ... </td></tr>";
+	  }
+	  format.value = JSON.stringify(structure);
+	  $('#generate_fitting_data').prop("disabled", false);
+	  $('#fitting_ventilation_states').prop('disabled', false);
+	  $('[name=fitting_ventilation_type]').prop('disabled', false);
+	  plotCO2Data(endpoint);
 	} else {
-		table.innerHTML = "There is no data in the spreadsheet file";
+	  table.innerHTML = "There is no data in the spreadsheet file";
 	}
-}
-
-// Method to download Excel template available on CERNBox
-function downloadTemplate(uri = 'https://caimira-resources.web.cern.ch/CO2_template.xlsx', filename = 'CO2_template.xlsx') {
-	var link = document.createElement("a");
+  }
+  
+  // Method to download Excel template available on CERNBox
+  function downloadTemplate(uri = 'https://caimira-resources.web.cern.ch/CO2_template.xlsx', filename = 'CO2_template.xlsx') {
+	const link = document.createElement("a");
 	link.download = filename;
 	link.href = uri;
 	document.body.appendChild(link);
 	link.click();
 	document.body.removeChild(link);
 	delete link;
-}
-
-function insertErrorFor(referenceNode, text) {
-	var element = document.createElement("span");
+  }
+  
+  function insertErrorFor(referenceNode, text) {
+	const element = document.createElement("span");
 	element.setAttribute("class", "error_text");
 	element.classList.add("red_text");
 	element.innerHTML = "&nbsp;&nbsp;" + text;
 	$(referenceNode).before(element);
-}
-
-function validate() {
+  }
+  
+  function validateFormInputs(obj) {
 	$('span.' + "error_text").remove();
 	let submit = true;
-	for (var i = 0; i < CO2_data_form.length; i++) {
-		let element = $(`[name=${CO2_data_form[i]}]`)[0];
-		if (element.value === '') {
-			insertErrorFor($('#CO2_input_data_div'), `'${element.name}' must be defined.`); // raise error for total number and room volume.
+	for (let i = 0; i < CO2_data_form.length; i++) {
+	  const element = $(`[name=${CO2_data_form[i]}]`)[0];
+	  if (element.name !== 'fitting_ventilation_states' && element.value === '') {
+		insertErrorFor($('#DIVCO2_data_dialog'), `'${element.name}' must be defined.<br />`);
+		submit = false;
+	  }
+	}
+	if (submit) {
+	  $($(obj).data('target')).modal('show');
+	}
+	return submit;
+  }  
+
+function validateCO2Form() {
+	let submit = true;
+	if (validateFormInputs($('#button_fit_data'))) submit = true;
+	
+	// Check if natural ventilation is selected
+	if ($('input[name="fitting_ventilation_type"]:checked')[0].value == 'fitting_natural_ventilation') {
+		// Validate ventilation scheme
+		const element = $('[name=fitting_ventilation_states')[0]
+		if (element.value !== '') {
+			// validate input format
+			try {
+				const parsedValue = JSON.parse(element.value);
+          		if (!Array.isArray(parsedValue)) {
+					insertErrorFor($('#DIVCO2_fitting_result'), `'${element.name}' must be a list.</br>`);
+					submit = false;
+				};
+			} catch {
+				insertErrorFor($('#DIVCO2_fitting_result'), `'${element.name}' must be a list of numbers.</br>`);
+				submit = false;
+			};
+		} else {
+			insertErrorFor($('#DIVCO2_fitting_result'), `'${element.name}' must be defined.</br>`);
 			submit = false;
 		};
-	}
+	};
+
 	return submit;
 }
 
-function display_transition_times_hour_format(start, stop) {
-	var minutes_start = start % 1 * 60;
-	var minutes_stop = stop % 1 * 60;
-	return Math.floor(start) + ':' + minutes_start.toPrecision(2) + ' - ' + Math.floor(stop) + ':' + minutes_stop.toPrecision(2);
+function displayTransitionTimesHourFormat(start, stop) {
+	var minutes_start = (start % 1 * 60).toPrecision(2);
+	var minutes_stop = (stop % 1 * 60).toPrecision(2);
+	return Math.floor(start) + ':' + ((minutes_start != '0.0') ? minutes_start : '00') + ' - ' + Math.floor(stop) + ':' + ((minutes_stop != '0.0') ? minutes_stop : '00');
 }
 
-function display_fitting_data(json_response) {
-	$("#DIV_CO2_fitting_result").show();
+function displayFittingData(json_response) {
+	$("#DIVCO2_fitting_result").show();
 	$("#CO2_data_plot").attr("src", json_response['CO2_plot']);
 	// Not needed for the form submit
 	delete json_response['CO2_plot']; 
 	$("#CO2_fitting_result").val(JSON.stringify(json_response));
 	$("#exhalation_rate_fit").html('Exhalation rate: ' + String(json_response['exhalation_rate'].toFixed(2)) + ' m³/h');
 	let ventilation_table = "<tr><th>Time (HH:MM)</th><th>ACH value (h⁻¹)</th></tr>";
-	json_response['ventilation_values'].map((val, index) => {
-		let transition_times = display_transition_times_hour_format(json_response['transition_times'][index], json_response['transition_times'][index + 1]);
+	json_response['ventilation_values'].forEach((val, index) => {
+		let transition_times = displayTransitionTimesHourFormat(json_response['transition_times'][index], json_response['transition_times'][index + 1]);
 		ventilation_table += `<tr><td>${transition_times}</td><td>${val.toPrecision(2)}</td></tr>`;
 	});
+	$('#disable_fitting_algorithm').prop('disabled', false);
 	$("#ventilation_rate_fit").html(ventilation_table);
 	$("#generate_fitting_data").html('Fit data');
 	$("#generate_fitting_data").hide();
 	$("#save_and_dismiss_dialog").show();
 }
 
-function submit_fitting_algorithm(url) {
-	if (validate()) {
-		let CO2_mapping = {};
-		CO2_data_form.map(el => {
-			let element = $(`[name=${el}]`);
-			// Validate radio buttons
-			if (element.length != 1) CO2_mapping[element[0].name] = $(`[name=${element[0].name}]:checked`)[0].value
-			else CO2_mapping[element[0].name] = element[0].value;
-		})
-		$('#CO2_input_data_div').show();
-		$("#generate_fitting_data").html(
-			`<span id="loading_spinner" class="spinner-border spinner-border-sm mr-2" role="status" aria-hidden="true" disabled ></span>Loading...`
-		  );
-		$('#CO2_input_data').html(JSON.stringify(CO2_mapping, null, "\t"))
+function formatCO2DataForm(CO2_data_form) {
+	let CO2_mapping = {};
+	CO2_data_form.map(el => {
+		let element = $(`[name=${el}]`);
+		// Validate checkboxes
+		if (element[0].type == 'checkbox') {
+			CO2_mapping[element[0].name] = String(+element[0].checked);
+		}
+		// Validate radio buttons
+		else if (element[0].type == 'radio') CO2_mapping[element[0].name] = $(`[name=${element[0].name}]:checked`)[0].value;
+		else CO2_mapping[element[0].name] = element[0].value;
+	});
+	return CO2_mapping;
+}
+
+function plotCO2Data(url) {
+	if (validateFormInputs()) {
+		let CO2_mapping = formatCO2DataForm(CO2_data_form);
 		fetch(url, {
 			method: "POST",
 			body: JSON.stringify(CO2_mapping),
 		})
-			.then((response) => response.json())
-			.then((json_response) => {
-				display_fitting_data(json_response);
-			});
+			.then((response) => 
+				response.json()
+					.then(json_response => $("#CO2_data_plot").attr("src", json_response['CO2_plot']))
+					.then($('#DIVCO2_fitting_to_submit').show())
+					.catch(error => console.log(error))
+			);
 	}
 }
 
-function clear_fitting_result_component() {
-	$('#generate_fitting_data').prop("disabled", true);
-	$("#display_excel_data tbody").remove();
+function submitFittingAlgorithm(url) {
+	if (validateCO2Form()) {
+	  // Disable all the ventilation inputs
+	  $('#fitting_ventilation_states, [name=fitting_ventilation_type]').prop('disabled', true);
+  
+	  // Prepare data for submission
+	  const CO2_mapping = formatCO2DataForm(CO2_data_form);
+	  $('#CO2_input_data_div').show();
+	  $('#disable_fitting_algorithm').prop('disabled', true);
+	  $('#generate_fitting_data')
+		.html('<span id="loading_spinner" class="spinner-border spinner-border-sm mr-2" role="status" aria-hidden="true"></span>Loading...')
+		.prop('disabled', true);
+	  $('#CO2_input_data').html(JSON.stringify(CO2_mapping, null, '\t'));
+  
+	  fetch(url, {
+		method: 'POST',
+		body: JSON.stringify(CO2_mapping),
+	  })
+		.then((response) => response.json())
+		.then((json_response) => {
+		  displayFittingData(json_response);
+		});
+	}
+  }
+  
+  function clearFittingResultComponent() {
+	// Remove all the previously generated fitting elements
+	$('#generate_fitting_data').prop('disabled', true);
 	$('#CO2_fitting_result').val('');
-	$('#formatted_data').val('');
-	$('span.' + "error_text").remove();
-	$('#DIV_CO2_fitting_result').hide();
-	$('#CO2_input_data_div').hide();
-}
-
-function clear_fitting_algorithm() {
-	clear_fitting_result_component();
-	$('#CO2_data_no').click(); 
-	ventilation_from_fitting(false);
-}
+	$('#CO2_data').val('{}');
+	$('#fitting_ventilation_states').val('');
+	$('span.error_text').remove();
+	$('#DIVCO2_fitting_result, #CO2_input_data_div').hide();
+	$('#CO2_data_plot').attr('src', '');
+  
+	// Update the ventilation scheme components
+	$('#fitting_ventilation_states, [name=fitting_ventilation_type]').prop('disabled', false);
+  
+	// Update the bottom right buttons
+	$('#generate_fitting_data').show();
+	$('#save_and_dismiss_dialog').hide();
+  }
+  
+  function disableFittingAlgorithm() {
+	clearFittingResultComponent();
+	$('#CO2_data_no').click();
+  }
+  
diff --git a/caimira/apps/calculator/static/js/form.js b/caimira/apps/calculator/static/js/form.js
index 72eff671..f497a3c4 100644
--- a/caimira/apps/calculator/static/js/form.js
+++ b/caimira/apps/calculator/static/js/form.js
@@ -247,8 +247,6 @@ function on_ventilation_type_change() {
   ventilation_types = $('input[type=radio][name=ventilation_type]');
   ventilation_types.each(function (index) {
     if (this.checked) {
-      
-      if ($(this).val() != 'from_fitting') $('#button_fit_data').attr('data-previous-vent', $(this).val())
       getChildElement($(this)).show();
       require_fields(this);
     } else {
@@ -495,32 +493,13 @@ function on_coffee_break_option_change() {
   }
 }
 
-function ventilation_from_fitting(condition_from_fitting) {
-  $('input[type=radio][id=no_ventilation]').prop("disabled", condition_from_fitting);
-  $('input[type=radio][id=mechanical_ventilation]').prop("disabled", condition_from_fitting);
-  $('input[type=radio][id=natural_ventilation]').prop("disabled", condition_from_fitting);
-  $('input[type=radio][id=from_fitting]').prop("disabled", !condition_from_fitting);
-  if (condition_from_fitting) {
-    $('input[type=radio][id=from_fitting]').prop('checked',true);
-    $('#DIVfrom_fitting').after($('#window_opening_regime'));
-  }
-  else {
-    let selected_ventilation = $("#button_fit_data").attr('data-previous-vent');
-    $(`input[type=radio][id=${selected_ventilation}]`).prop('checked',true);
-    $('#DIVopening_distance').after($('#window_opening_regime'));
-  }
-  on_ventilation_type_change();
-}
-
-function on_CO2_data_option_change() {
-  CO2_data_options = $('input[type=radio][name=CO2_data_option]');
-  CO2_data_options.each(function (index){
+function on_CO2_fitting_ventilation_change() {
+  ventilation_options = $('input[type=radio][name=fitting_ventilation_type]');
+  ventilation_options.each(function (index) {
     if (this.checked) {
-      if (this.id == 'CO2_data_yes') ventilation_from_fitting(true);
-      else if (this.id == 'CO2_data_no') ventilation_from_fitting(false);
       getChildElement($(this)).show();
       require_fields(this);
-    } 
+    }
     else {
       getChildElement($(this)).hide();
       require_fields(this);
@@ -700,6 +679,13 @@ function validate_form(form) {
     on_short_range_option_change();
   }
 
+  // Check if fitting is selected
+  if ($('input[type=radio][id=from_fitting]').prop('checked')  ) {
+    if ($('#CO2_fitting_result').val() == '')
+    $("input[type=radio][id=no_ventilation]").prop("checked", true);
+    on_ventilation_type_change();
+  }
+
   if (submit) {
     $("#generate_report").prop("disabled", true);
     //Add spinner to button
@@ -969,7 +955,7 @@ $(document).ready(function () {
 
   // Populate CO2 Fitting Algorithm Dialog
   let CO2_data = url.searchParams.has('CO2_fitting_result') ? url.searchParams.get('CO2_fitting_result') : null;
-  if (CO2_data) display_fitting_data(JSON.parse(CO2_data));
+  if (CO2_data) displayFittingData(JSON.parse(CO2_data));
 
   // Populate primary vaccine dropdown
   $("#vaccine_type option").remove();
@@ -1086,11 +1072,11 @@ $(document).ready(function () {
   // Call the function now to handle forward/back button presses in the browser.
   on_coffee_break_option_change();
 
-  // When the CO2_data_option changes we want to make its respective
+  // When the ventilation on the fitting changes we want to make its respective
   // children show/hide.
-  $("input[type=radio][name=CO2_data_option]").change(on_CO2_data_option_change);
+  $("input[type=radio][name=fitting_ventilation_type]").change(on_CO2_fitting_ventilation_change);
   // Call the function now to handle forward/back button presses in the browser.
-  on_CO2_data_option_change();
+  on_CO2_fitting_ventilation_change();
 
   // Setup the maximum number of people at page load (to handle back/forward),
   // and update it when total people is changed.