{"id":5351,"date":"2026-11-06T00:35:41","date_gmt":"2026-11-06T08:35:41","guid":{"rendered":"https:\/\/www.26yc.com\/tools\/frost-estimator\/"},"modified":"2026-11-06T00:35:41","modified_gmt":"2026-11-06T08:35:41","slug":"frost-estimator","status":"publish","type":"page","link":"https:\/\/www.26yc.com\/de\/tools\/frost-estimator\/","title":{"rendered":"Frost &#038; Condensation Risk Estimator"},"content":{"rendered":"<p>In cold climates the exhaust side of a heat exchanger can fall below the frost point, and ice build-up raises pressure drop and can block the core. Enter your outdoor, exhaust and indoor conditions plus the core type to estimate whether a preheat coil, bypass damper or defrost cycle is required before you finalize the selection. This is a first-order screening tool; verify against EN 308 or AHRI 1060 test data and the project design conditions.<\/p>\n<style>\r\n.yc-tp-frost-estimator{font-family:-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;color:#222;line-height:1.6;--ink:#1a3c5e;--accent:#0f6e56;--bg:#f5f8fa;--card:#fff;--line:#dce4ea;--muted:#5f6b75}\r\n.yc-tp-frost-estimator h1{color:var(--ink);font-size:26px;margin:8px 0 6px}\r\n.yc-tp-frost-estimator .lead{color:var(--muted);margin:0 0 22px}\r\n.yc-tp-frost-estimator .card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:18px;margin-bottom:16px}\r\n.yc-tp-frost-estimator .card h2{font-size:15px;margin:0 0 12px;color:var(--accent);text-transform:uppercase;letter-spacing:.04em}\r\n.yc-tp-frost-estimator .row{display:flex;align-items:center;gap:8px;margin:10px 0}\r\n.yc-tp-frost-estimator .row label{flex:0 0 200px;font-size:14px;color:#33414c}\r\n.yc-tp-frost-estimator .row input, .yc-tp-frost-estimator .row select{flex:1;min-width:0;padding:9px 10px;border:1px solid var(--line);border-radius:8px;font-size:15px}\r\n.yc-tp-frost-estimator .row input:focus, .yc-tp-frost-estimator .row select:focus{outline:2px solid var(--accent);border-color:var(--accent)}\r\n.yc-tp-frost-estimator .row .u{flex:0 0 48px;font-size:12px;color:var(--muted)}\r\n.yc-tp-frost-estimator button.calc{background:var(--accent);color:#fff;border:0;border-radius:8px;padding:11px 18px;font-size:15px;font-weight:500;cursor:pointer;margin-top:6px}\r\n.yc-tp-frost-estimator .result{margin-top:16px;padding:16px;border-radius:10px;font-size:15px}\r\n.yc-tp-frost-estimator .ok{background:#eaf3ef;border:1px solid #bfe0d2;color:#0f5132}\r\n.yc-tp-frost-estimator .warn{background:#fff4e5;border:1px solid #f0c98a;color:#7a4b00}\r\n.yc-tp-frost-estimator .bad{background:#fdeaea;border:1px solid #f0a9a9;color:#8a1f1f}\r\n.yc-tp-frost-estimator .result h3{margin:0 0 8px;font-size:16px}\r\n.yc-tp-frost-estimator .result table{width:100%;border-collapse:collapse;margin-top:8px;font-size:14px}\r\n.yc-tp-frost-estimator .result td{padding:5px 8px;border-top:1px solid rgba(0,0,0,.06)}\r\n.yc-tp-frost-estimator .result td:first-child{color:var(--muted)}\r\n.yc-tp-frost-estimator .note{font-size:12px;color:var(--muted);margin-top:10px}\r\n.yc-tp-frost-estimator .cta{margin-top:8px;background:#eaf3ef;border:1px solid #bfe0d2;border-radius:12px;padding:18px}\r\n.yc-tp-frost-estimator .cta h2{margin:0 0 8px;color:var(--ink);font-size:18px}\r\n.yc-tp-frost-estimator .cta a.btn{display:inline-block;background:var(--accent);color:#fff;text-decoration:none;padding:10px 16px;border-radius:8px;font-weight:500;margin-top:8px}\r\n.yc-tp-frost-estimator .cta .phone{font-weight:600;color:var(--ink)}\r\n.yc-tp-frost-estimator .links{margin-top:14px;font-size:13px;color:var(--muted)}\r\n.yc-tp-frost-estimator .links a{color:var(--accent);text-decoration:none}\r\n<\/style>\r\n<div class=\"yc-tp yc-tp-frost-estimator\">\r\n\r\n  \r\n  <p class=\"lead\">A quick screening tool for air-to-air heat exchangers in cold climates. Enter your air conditions and exchanger type to see whether frost or condensation is likely &mdash; and what to do about it.<\/p>\r\n\r\n  <div class=\"card\">\r\n    <h2>Air conditions<\/h2>\r\n    <div class=\"row\"><label>Outdoor air temperature<\/label><input id=\"t_out\" type=\"number\" step=\"0.1\" value=\"-8\"><span class=\"u\">&deg;C<\/span><\/div>\r\n    <div class=\"row\"><label>Outdoor relative humidity<\/label><input id=\"rh_out\" type=\"number\" step=\"1\" value=\"70\"><span class=\"u\">%<\/span><\/div>\r\n    <div class=\"row\"><label>Exhaust (indoor) temperature<\/label><input id=\"t_exh\" type=\"number\" step=\"0.1\" value=\"22\"><span class=\"u\">&deg;C<\/span><\/div>\r\n    <div class=\"row\"><label>Exhaust relative humidity<\/label><input id=\"rh_exh\" type=\"number\" step=\"1\" value=\"60\"><span class=\"u\">%<\/span><\/div>\r\n    <div class=\"row\"><label>Exchanger type<\/label>\r\n      <select id=\"type\">\r\n        <option value=\"plate\">Plate (effectiveness ~0.72)<\/option>\r\n        <option value=\"rotary\">Rotary wheel (effectiveness ~0.82)<\/option>\r\n        <option value=\"heatpipe\">Heat pipe (effectiveness ~0.60)<\/option>\r\n      <\/select>\r\n    <\/div>\r\n    <div class=\"row\"><label>Preheat outdoor air?<\/label>\r\n      <select id=\"preheat\">\r\n        <option value=\"0\">No preheat<\/option>\r\n        <option value=\"5\">Yes, +5 &deg;C<\/option>\r\n        <option value=\"10\">Yes, +10 &deg;C<\/option>\r\n      <\/select>\r\n    <\/div>\r\n    <button class=\"calc\" id=\"go\">Estimate risk<\/button>\r\n    <div class=\"note\">Simplified screening model using the Magnus dew-point formula and a representative effectiveness per type. Not a substitute for manufacturer sizing or freeze-protection design.<\/div>\r\n  <\/div>\r\n\r\n  <div class=\"result ok\" id=\"out\" style=\"display:none\"><\/div>\r\n\r\n  <section class=\"cta\">\r\n    <h2>Designing for a cold-climate project?<\/h2>\r\n    <p>Our engineers can specify freeze protection &mdash; preheat coils, bypass strategies or heat-pipe selection &mdash; for your exact conditions.<\/p>\r\n    <p class=\"phone\">Call: 15753355505<\/p>\r\n    <a class=\"btn\" href=\"https:\/\/www.26yc.com\/contact-us\/\">Request a quote &rarr;<\/a>\r\n    <div class=\"links\">\r\n      Products:\r\n      <a href=\"https:\/\/www.26yc.com\/products\/air-to-air-heat-exchanger\/\">Air-to-Air<\/a> &\r\n      <a href=\"https:\/\/www.26yc.com\/products\/plate-heat-exchanger\/\">Plate<\/a> &\r\n      <a href=\"https:\/\/www.26yc.com\/products\/rotary-heat-wheel\/\">Rotary Wheel<\/a> &\r\n      <a href=\"https:\/\/www.26yc.com\/products\/heat-pipe-heat-exchanger\/\">Heat Pipe<\/a> |\r\n      <a href=\"https:\/\/www.26yc.com\/industrial\/heat-exchanger\/\">Heat Exchanger Guide<\/a><br>\r\n      Tools:\r\n      <a href=\"https:\/\/www.26yc.com\/tools\/selection-guide\/\">Type comparison<\/a> &middot;\r\n      <a href=\"https:\/\/www.26yc.com\/tools\/application-wizard\/\">Application selector<\/a> &middot;\r\n      <a href=\"https:\/\/www.26yc.com\/tools\/standards-glossary\/\">Standards &amp; glossary<\/a>\r\n    <\/div>\r\n  <\/section>\r\n\r\n<\/div>\r\n<script>\r\n\r\nfunction dewPoint(T,RH){\r\n  var a=17.625,b=243.04;\r\n  var al=Math.log(Math.max(RH,1)\/100)+ (a*T)\/(b+T);\r\n  return (b*al)\/(a-al);\r\n}\r\ndocument.getElementById('go').addEventListener('click',function(){\r\n  var t_out=parseFloat(document.getElementById('t_out').value);\r\n  var rh_out=parseFloat(document.getElementById('rh_out').value);\r\n  var t_exh=parseFloat(document.getElementById('t_exh').value);\r\n  var rh_exh=parseFloat(document.getElementById('rh_exh').value);\r\n  var type=document.getElementById('type').value;\r\n  var pre=parseFloat(document.getElementById('preheat').value)||0;\r\n  if([t_out,rh_out,t_exh,rh_exh].some(function(v){return isNaN(v);})){alert('Please fill all fields.');return;}\r\n\r\n  var eff = type==='rotary'?0.82 : type==='heatpipe'?0.60 : 0.72;\r\n  var t_in = t_out + pre;                       \/\/ after preheat\r\n  var td_out = dewPoint(t_out,rh_out);\r\n  var td_exh = dewPoint(t_exh,rh_exh);\r\n  var ts = t_in + eff*(t_exh - t_in);           \/\/ supply temp after recovery\r\n  var t_cold = t_in + 0.30*(ts - t_in);        \/\/ cold-corner surface estimate\r\n\r\n  var cls,head,msg,advice;\r\n  if(t_cold < 0 && t_cold < td_exh){\r\n    cls='bad'; head='Frost risk: HIGH';\r\n    msg='The cold exhaust-side surface reaches about '+t_cold.toFixed(1)+' C, below both 0 C and the exhaust dew point ('+td_exh.toFixed(1)+' C). Frost will form and accumul\\x61te without mitigation.';\r\n    advice='Add freeze protection: preheat the outdoor air, recirculate a controlled exhaust fraction, use a winter bypass, or select a heat-pipe unit with passive frost control.';\r\n  } else if(t_cold < td_exh){\r\n    cls='warn'; head='Condensation risk: MODERATE';\r\n    msg='The cold surface (~'+t_cold.toFixed(1)+' C) is below the exhaust dew point ('+td_exh.toFixed(1)+' C) but above 0 C, so moisture condenses (no freeze). Drainage and coating are needed.';\r\n    advice='Ensure condensate drainage and consider a hydrophobic coating or periodic purge. Monitor for microbial growth in the condensate path.';\r\n  } else {\r\n    cls='ok'; head='Low risk';\r\n    msg='The cold surface (~'+t_cold.toFixed(1)+' C) stays above the exhaust dew point ('+td_exh.toFixed(1)+' C). No condensation or frost expected under these conditions.';\r\n    advice='Standard design is fine. Re-check if outdoor temperatures drop further in peak winter.';\r\n  }\r\n\r\n  var html='<h3>'+head+'<\/h3>'+\r\n    '<table>'+\r\n    '<tr><td>Outdoor dew point<\/td><td>'+td_out.toFixed(1)+' C<\/td><\/tr>'+\r\n    '<tr><td>Exhaust dew point<\/td><td>'+td_exh.toFixed(1)+' C<\/td><\/tr>'+\r\n    '<tr><td>Supply temp after recovery<\/td><td>'+ts.toFixed(1)+' C<\/td><\/tr>'+\r\n    '<tr><td>Cold-corner surface (est.)<\/td><td>'+t_cold.toFixed(1)+' C<\/td><\/tr>'+\r\n    '<tr><td>Assumed effectiveness<\/td><td>'+eff.toFixed(2)+'<\/td><\/tr>'+\r\n    '<\/table>'+\r\n    '<p style=\"margin:10px 0 0\">'+msg+'<\/p>'+\r\n    '<p style=\"margin:8px 0 0\"><strong>Recommendation:<\/strong> '+advice+'<\/p>';\r\n  var box=document.getElementById('out');\r\n  box.className='result '+cls;\r\n  box.innerHTML=html;\r\n  box.style.display='block';\r\n  box.scrollIntoView({behavior:'smooth',block:'nearest'});\r\n});\r\n\r\n<\/script>\n<h2>How to use this tool in a specification<\/h2>\n<p>These results are a first-pass screening aid. Confirm the duty point against certified test data (EN 308 \/ AHRI 1060), the applicable energy code, and the manufacturer datasheet before issuing a purchase specification. For a verified sizing, <a href=\"\/contact-us\/\">send us your airflow and temperatures<\/a>.<\/p>\n<h2>Frequently asked questions<\/h2>\n<h3>When does a heat exchanger frost up?<\/h3>\n<p>Frost forms when the cold exhaust-side surface temperature drops below 0 C AND below the exhaust air dew point. This typically happens in cold climates with humid indoor exhaust (kitchens, pools, labs) when outdoor air is below about -5 to -10 C depending on exchanger effectiveness.<\/p>\n<h3>Which heat exchanger type resists frost best?<\/h3>\n<p>Plate and rotary exchangers are most efficient but most frost-prone at the cold corner. Heat-pipe exchangers tolerate frost better and allow built-in frost-control strategies, though at lower effectiveness. The right choice depends on climate and exhaust humidity.<\/p>\n<h3>How do you prevent frost in an air-to-air heat exchanger?<\/h3>\n<p>Common methods: preheat the incoming outdoor air, recirculate a controlled fraction of exhaust air, use a summer\/winter bypass, or select a heat-pipe unit with passive frost control. Our estimator shows whether mitigation is needed for your conditions.<\/p>\n<h3>What is the dew point used for here?<\/h3>\n<p>The dew point is the temperature at which moisture condenses out of air at a given humidity. If any surface in the exchanger falls below the exhaust-air dew point, condensation (or frost, if also below 0 C) occurs on that surface.<\/p>\n<h2>Continue reading<\/h2>\n<p>Related: <a href=\"\/plate-heat-exchanger-frost-protection\/\">frost protection design<\/a>, <a href=\"\/tools\/selection-guide\/\">exchanger type comparison<\/a>, <a href=\"\/which-climate-zone-mandates-heat-recovery\/\">climate-zone requirements<\/a> &middot; <a href=\"\/tools\/\">all heat recovery tools<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In cold climates the exhaust side of a heat exchanger can fall below the frost point, and ice build-up raises pressure drop and can block the core. Enter your outdoor, exhaust and indoor conditions plus the core type to estimate whether a preheat coil, bypass damper or defrost cycle is required before you finalize the [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":0,"parent":5323,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-5351","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/pages\/5351","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/types\/page"}],"replies":[{"embeddable":true,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/comments?post=5351"}],"version-history":[{"count":0,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/pages\/5351\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/pages\/5323"}],"wp:attachment":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/media?parent=5351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}