{"id":100089,"date":"2026-02-15T20:17:41","date_gmt":"2026-02-15T20:17:41","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100089"},"modified":"2026-02-15T20:17:41","modified_gmt":"2026-02-15T20:17:41","slug":"fan-selection-air-change","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/nb\/calculators\/fan-selection-air-change\/","title":{"rendered":"Viftevalg \u2013 Kalkulator for luftutskiftningshastighet | Gratis nettverkt\u00f8y"},"content":{"rendered":"\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Fan Selection \u2014 Air Change Rate Calculator\",\"description\":\"Free online fan selection \u2014 air change rate calculator.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/fan-selection-air-change\/\",\"applicationCategory\":\"Engineering Calculator\",\"operatingSystem\":\"Any\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"EUR\"},\"creator\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"datePublished\":\"2024-01-01\",\"dateModified\":\"2025-06-15\",\"inLanguage\":\"en\",\"isAccessibleForFree\":true}<\/script>\n\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"How many ACH do I need?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Office:4-6, Kitchen:12-20, Warehouse:4-8, Lab:8-15, Hospital:6-12.\"}},{\"@type\":\"Question\",\"name\":\"What is an air change?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Replacing entire room volume once. 6 ACH=6 replacements per hour.\"}},{\"@type\":\"Question\",\"name\":\"Convert m\u00b3\/h to CFM?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"1 CFM=1.699 m\u00b3\/h. Divide m\u00b3\/h by 1.699.\"}},{\"@type\":\"Question\",\"name\":\"Supply vs exhaust?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Calculate based on exhaust. Supply=exhaust \u00b110%.\"}},{\"@type\":\"Question\",\"name\":\"Does ACH include filtration?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. Filter \u0394P affects fan sizing but not ACH calculation.\"}}]}<\/script>\n\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"BreadcrumbList\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/vibromera.eu\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Calculators\",\"item\":\"https:\/\/vibromera.eu\/calculators\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Fan Selection \u2014 Air Change Rate Calculator\",\"item\":\"https:\/\/vibromera.eu\/calculators\/fan-selection-air-change\/\"}]}<\/script>\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n\n<link 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print{.vc-section-body{max-height:none!important}.vc-faq-a{max-height:none!important}.vc-results{max-height:none!important;padding:24px!important}.vc-copy-btn,.vc-section-chevron,.vc-faq-chevron,.vc-presets,.vc-promo{display:none!important}}<\/style>\n\n<div class=\"vc-calculator\">\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool \u2014 #158<\/p>\n    <h1 class=\"vc-header-title\">Fan Selection \u2014 Air Change Rate Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Q=V\u00d7ACH\/60. Calculate fan flow from room volume and air changes per hour.<\/p>\n    <div class=\"vc-badges\"><span class=\"vc-badge\">Q=V\u00d7ACH<\/span><span class=\"vc-badge\">m\u00b3\/h &#038; CFM<\/span><\/div>\n<\/header>\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-length\">Room Length <span class=\"vc-label-hint\">(m)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-length\" inputmode=\"decimal\" step=\"any\" value=\"10\"><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-width\">Room Width <span class=\"vc-label-hint\">(m)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-width\" inputmode=\"decimal\" step=\"any\" value=\"8\"><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-height\">Room Height <span class=\"vc-label-hint\">(m)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-height\" inputmode=\"decimal\" step=\"any\" value=\"3\"><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-ach\">Air Changes\/Hour <span class=\"vc-label-hint\">(ACH)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-ach\" inputmode=\"decimal\" step=\"any\" value=\"6\"><\/div>\n        <\/div>\n        <div class=\"vc-presets\">\n            <div class=\"vc-presets-label\">Quick presets<\/div>\n            <button type=\"button\" class=\"vc-preset-btn\" data-length=\"10\" data-width=\"8\" data-height=\"3\" data-ach=\"4\">Office 4 ACH<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-length=\"5\" data-width=\"4\" data-height=\"3\" data-ach=\"15\">Kitchen 15 ACH<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-length=\"30\" data-width=\"20\" data-height=\"6\" data-ach=\"6\">Warehouse 6 ACH<\/button>\n        <\/div>\n    <\/form>\n    <div class=\"vc-results\" id=\"vc-results\">\n        <div class=\"vc-results-head\"><h2 class=\"vc-results-title\">Results<\/h2><button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\"><svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy<\/button><\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\"><div class=\"vc-rcard-label\">Required Flow Rate<\/div><div class=\"vc-rcard-value\" id=\"vc-r-flow\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Flow (CFM)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-cfm\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Room Volume<\/div><div class=\"vc-rcard-value\" id=\"vc-r-vol\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Flow (L\/s)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-ls\">\u2014<\/div><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n<div class=\"vc-section vc-open\"><button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udcd8<\/span><span class=\"vc-section-title\">Theory &amp; Formulas<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner vc-theory\"><h3>Formula<\/h3><div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div><\/div><\/div><\/div>\n<div class=\"vc-section\"><button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udd17<\/span><span class=\"vc-section-title\">Related Calculators<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div class=\"vc-related\"><a class=\"vc-related-link\" href=\"\/calculators\/duct-pressure-loss\/\">Duct Pressure Loss<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/fan-shaft-power\/\">Fan Power<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/equivalent-duct-diameter\/\">Equiv. Duct Dia.<\/a><\/div><\/div><\/div><\/div>\n<div class=\"vc-section\"><button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\u2753<\/span><span class=\"vc-section-title\">Frequently Asked Questions<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div><\/div><\/div><\/div>\n<div class=\"vc-promo\"><div class=\"vc-promo-text\"><strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>Professional instruments. Used in 50+ countries.<\/div><a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a><\/div>\n<footer class=\"vc-footer\"><p>&copy; 2024&ndash;2025 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> &mdash; Engineering Calculators<\/p><p style=\"font-size:12px;margin-top:4px\">Fan Selection \u2014 Air Change Rate Calculator. Last updated: June 2025<\/p><div class=\"vc-footer-links\"><a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a><a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a><\/div><\/footer>\n<\/div>\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.js\"><\/script>\n<script>\n(function(){\n    'use strict';\n    function $(id){return document.getElementById(id)}\n    function fm(n,d){if(isNaN(n)||!isFinite(n))return '\\u2014';return n.toFixed(d===undefined?2:d).replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,'')}\n    function pf(id){return parseFloat($(id).value)}\n    function ok(){for(var i=0;i<arguments.length;i++){var v=arguments[i];if(!v||v<=0)return false}return true}\n    function R(id,val,unit){$(id).innerHTML=val+(unit?' <span class=\"vc-rcard-unit\">'+unit+'<\/span>':'')}\n    function show(){$('vc-results').classList.add('vc-visible')}\n    function hide(){$('vc-results').classList.remove('vc-visible')}\n    function calculate(){var L=pf('vc-length'),W=pf('vc-width'),H=pf('vc-height'),A=pf('vc-ach');if(!ok(L,W,H,A))return hide();\nvar V=L*W*H,Q=V*A;R('vc-r-flow',fm(Q,0),'m\u00b3\/h');R('vc-r-cfm',fm(Q\/1.699,0),'CFM');R('vc-r-vol',fm(V,0),'m\u00b3');R('vc-r-ls',fm(Q\/3.6,1),'L\/s');show();}\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn){btn.addEventListener('click',function(e){e.preventDefault();if(this.dataset.length)$('vc-length').value=this.dataset.length;if(this.dataset.width)$('vc-width').value=this.dataset.width;if(this.dataset.height)$('vc-height').value=this.dataset.height;if(this.dataset.ach)$('vc-ach').value=this.dataset.ach;calculate()})});\n    $('vc-form').addEventListener('input',calculate);$('vc-form').addEventListener('change',calculate);\n    $('vc-copy-btn').addEventListener('click',function(){var t='Fan Selection \u2014 Air Change Rate Calculator\\n'+$('vc-results').innerText.substring(0,300)+'\\nvibromera.eu';if(navigator.clipboard)navigator.clipboard.writeText(t).then(function(){var b=$('vc-copy-btn');b.classList.add('vc-copied');b.textContent='Copied!';setTimeout(function(){b.classList.remove('vc-copied');b.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy'},2000)})});\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn){btn.addEventListener('click',function(){var s=this.closest('.vc-section');s.classList.toggle('vc-open');this.setAttribute('aria-expanded',s.classList.contains('vc-open'))})});\n    var faqData=[{q:'How many ACH do I need?',a:'<p>Office:4-6, Kitchen:12-20, Warehouse:4-8, Lab:8-15, Hospital:6-12.<\/p>'},{q:'What is an air change?',a:'<p>Replacing entire room volume once. 6 ACH=6 replacements per hour.<\/p>'},{q:'Convert m\u00b3\/h to CFM?',a:'<p>1 CFM=1.699 m\u00b3\/h. 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