{"id":67119,"date":"2026-02-26T11:29:51","date_gmt":"2026-02-26T10:29:51","guid":{"rendered":"https:\/\/www.idm-energie.at\/?page_id=67119"},"modified":"2026-07-06T15:55:15","modified_gmt":"2026-07-06T13:55:15","slug":"defrost-impact","status":"publish","type":"page","link":"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/","title":{"rendered":"Defrost Impact"},"content":{"rendered":"<p><div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-1 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start fusion-flex-content-wrap\" style=\"max-width:1185.6px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-0 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><nav class=\"fusion-breadcrumbs fusion-breadcrumbs-1\" style=\"--awb-margin-top:1%;--awb-breadcrumb-sep:&#039;\/&#039;;\" aria-label=\"Breadcrumb\"><nav aria-label=\"breadcrumbs\" class=\"rank-math-breadcrumb\"><p><span class=\"last\">Home<\/span><\/p><\/nav><\/nav><div class=\"fusion-title title fusion-title-1 fusion-sep-none fusion-title-center fusion-title-text fusion-title-size-one\" style=\"--awb-margin-top:3%;--awb-margin-bottom:3%;--awb-margin-top-small:10px;--awb-margin-right-small:0px;--awb-margin-bottom-small:10px;--awb-margin-left-small:0px;\"><h1 class=\"fusion-title-heading title-heading-center fusion-responsive-typography-calculated\" style=\"margin:0;--fontSize:42;line-height:1;\">Defrost Impact on Heat Pump Efficiency<\/h1><\/div><div class=\"fusion-text fusion-text-1\"><p>Defrost impact describes how frost formation and defrost cycles affect the efficiency of an air-source heat pump.<\/p>\n<p>When outdoor temperatures are low and humidity is present, frost can form on the outdoor heat exchanger. This reduces heat transfer and requires periodic defrost cycles. During these cycles, the heat pump temporarily consumes energy without delivering useful heating to the building.<\/p>\n<p>Understanding defrost impact helps explain why efficiency drops under certain winter conditions.<\/p>\n<\/div><\/div><\/div><\/div><\/div><div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-2 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-stretch fusion-flex-justify-content-center fusion-flex-content-wrap\" style=\"max-width:1185.6px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-1 fusion-flex-column\" style=\"--awb-padding-top:1%;--awb-padding-right:2%;--awb-padding-left:2%;--awb-overflow:hidden;--awb-bg-color:#fff042;--awb-bg-color-hover:#fff042;--awb-bg-size:cover;--awb-border-radius:16px 16px 16px 16px;--awb-width-large:800px;--awb-margin-top-large:0px;--awb-spacing-right-large:2%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:2%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-title title fusion-title-2 fusion-sep-none fusion-title-center fusion-title-text fusion-title-size-paragraph blink-heading\" style=\"--awb-margin-top-small:10px;--awb-margin-right-small:0px;--awb-margin-bottom-small:10px;--awb-margin-left-small:0px;--awb-font-size:20px;\"><p class=\"fusion-title-heading title-heading-center title-heading-tag fusion-responsive-typography-calculated\" style=\"margin:0;text-transform:uppercase;font-size:1em;--fontSize:20;line-height:1.8;\"><strong>Configure your personalized heat pump system!<\/strong><\/p><\/div><div class=\"fusion-builder-row fusion-builder-row-inner fusion-row fusion-flex-align-items-stretch fusion-flex-justify-content-center fusion-flex-content-wrap\" style=\"--awb-flex-grow:0;--awb-flex-grow-medium:0;--awb-flex-grow-small:0;--awb-flex-shrink:0;--awb-flex-shrink-medium:0;--awb-flex-shrink-small:0;width:104% !important;max-width:104% !important;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-0 fusion_builder_column_inner_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:-5px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-2\" style=\"--awb-margin-left:2%;\"><p style=\"text-align: left;\">Plan your heat pump system with iDM Energiesysteme. Discover efficient heating, cooling, and hot water solutions for new buildings, renovations, and modern energy systems. Configure and personalize your iDM heat pump solution in just a few clicks.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-1 fusion_builder_column_inner_2_3 2_3 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:66.666666666667%;--awb-margin-top-large:0px;--awb-spacing-right-large:2.88%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:2.88%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-3\"><div style=\"display: flex; align-items: center; gap: 15px; flex-wrap: wrap;\">\n<div style=\"display: flex;\"><img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73518 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-150x150.jpg\" alt=\"Thomas Pletzer\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73509 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-150x150.jpg\" alt=\"Matthias Steiner\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73500 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-150x150.jpg\" alt=\"Christian Hutter\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73491 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-150x150.jpg\" alt=\"Adrian Egger\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/div>\n<div style=\"color: #000000; line-height: 0.7; margin-left: 2%;\"><strong style=\"display: block;\">CONNECT WITH OUR EXPERTS<\/strong><br \/>\n<span style=\"opacity: 0.8;\">50+ Years of Heat Pumps Experience<\/span><\/div>\n<\/div>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-2 fusion_builder_column_inner_1_3 1_3 fusion-flex-column fusion-flex-align-self-center\" style=\"--awb-bg-size:cover;--awb-width-large:33.333333333333%;--awb-margin-top-large:0px;--awb-spacing-right-large:5.76%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:5.76%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-center fusion-content-layout-column\"><div style=\"text-align:center;\"><a class=\"fusion-button button-flat fusion-button-default-size button-default fusion-button-default button-1 fusion-button-default-span fusion-button-default-type\" target=\"_self\" href=\"https:\/\/konfigurator.myidm.at\/#\/?lang=EN\" rel=\"noopener\"><span class=\"fusion-button-text awb-button__text awb-button__text--default\">Configure Now!<\/span><\/a><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-3 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start fusion-flex-content-wrap\" style=\"max-width:1185.6px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-2 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-4\">\n<\/div><div class=\"fusion-text fusion-text-5\"><div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#Why_Frost_Forms_on_Air-Source_Heat_Pumps\" >Why Frost Forms on Air-Source Heat Pumps<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#What_Is_a_Defrost_Cycle\" >What Is a Defrost Cycle?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#How_Defrost_Affects_Efficiency\" >How Defrost Affects Efficiency<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#Defrost_in_Standardized_Testing\" >Defrost in Standardized Testing<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#Air-Source_vs_Ground-Source_Systems\" >Air-Source vs Ground-Source Systems<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#When_Is_Defrost_Impact_Strongest\" >When Is Defrost Impact Strongest?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#Does_Defrost_Significantly_Reduce_Seasonal_Efficiency\" >Does Defrost Significantly Reduce Seasonal Efficiency?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#System_Design_and_Defrost_Optimization\" >System Design and Defrost Optimization<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.idm-energie.at\/en\/heat-pump-efficiency\/defrost-impact\/#Frequently_Asked_Questions_FAQs\" >Frequently Asked Questions (FAQs)<\/a><\/li><\/ul><\/nav><\/div>\n<h2 data-start=\"545\" data-end=\"588\"><span class=\"ez-toc-section\" id=\"Why_Frost_Forms_on_Air-Source_Heat_Pumps\"><\/span>Why Frost Forms on Air-Source Heat Pumps<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"590\" data-end=\"648\">Air-source heat pumps extract heat from outdoor air. When:<\/p>\n<ul data-start=\"650\" data-end=\"731\">\n<li data-start=\"650\" data-end=\"694\">\n<p data-start=\"652\" data-end=\"694\">Outdoor temperature is near or below 0\u00b0C<\/p>\n<\/li>\n<li data-start=\"695\" data-end=\"731\">\n<p data-start=\"697\" data-end=\"731\">Air humidity is moderate to high<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"733\" data-end=\"792\">Moisture in the air can freeze on the outdoor coil surface.<\/p>\n<p data-start=\"794\" data-end=\"808\">Frost buildup:<\/p>\n<ul data-start=\"810\" data-end=\"906\">\n<li data-start=\"810\" data-end=\"829\">\n<p data-start=\"812\" data-end=\"829\">Reduces airflow<\/p>\n<\/li>\n<li data-start=\"830\" data-end=\"857\">\n<p data-start=\"832\" data-end=\"857\">Decreases heat transfer<\/p>\n<\/li>\n<li data-start=\"858\" data-end=\"891\">\n<p data-start=\"860\" data-end=\"891\">Increases compressor workload<\/p>\n<\/li>\n<li data-start=\"892\" data-end=\"906\">\n<p data-start=\"894\" data-end=\"906\">Lowers COP<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"908\" data-end=\"980\">To maintain performance, the system must periodically remove this frost.<\/p>\n<\/div><div class=\"fusion-image-element\" style=\"text-align:center;--awb-margin-top:2%;--awb-margin-bottom:2%;--awb-caption-title-font-family:var(--h2_typography-font-family);--awb-caption-title-font-weight:var(--h2_typography-font-weight);--awb-caption-title-font-style:var(--h2_typography-font-style);--awb-caption-title-size:var(--h2_typography-font-size);--awb-caption-title-transform:var(--h2_typography-text-transform);--awb-caption-title-line-height:var(--h2_typography-line-height);--awb-caption-title-letter-spacing:var(--h2_typography-letter-spacing);\"><span class=\" fusion-imageframe imageframe-none imageframe-1 hover-type-none\" style=\"border:3px solid #333333;\"><img decoding=\"async\" width=\"1024\" height=\"559\" alt=\"Diagram comparing normal heating efficiency to the defrost impact on heat pump COP.\" title=\"defrost-impact\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-1024x559.webp\" class=\"img-responsive wp-image-67134\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-200x109.webp 200w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-400x218.webp 400w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-600x327.webp 600w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-800x436.webp 800w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/02\/defrost-impact-1200x655.webp 1200w\" sizes=\"(max-width: 1024px) 100vw, (max-width: 640px) 100vw, 1200px\" \/><\/span><\/div><div class=\"fusion-text fusion-text-6\"><h2 data-start=\"987\" data-end=\"1014\"><span class=\"ez-toc-section\" id=\"What_Is_a_Defrost_Cycle\"><\/span>What Is a Defrost Cycle?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1016\" data-end=\"1105\">A defrost cycle is an automatic process that removes ice from the outdoor heat exchanger.<\/p>\n<p data-start=\"1107\" data-end=\"1166\">Most air-source systems use a reverse-cycle defrost method:<\/p>\n<ul data-start=\"1168\" data-end=\"1310\">\n<li data-start=\"1168\" data-end=\"1216\">\n<p data-start=\"1170\" data-end=\"1216\">The refrigeration cycle temporarily reverses<\/p>\n<\/li>\n<li data-start=\"1217\" data-end=\"1257\">\n<p data-start=\"1219\" data-end=\"1257\">Heat is directed to the outdoor coil<\/p>\n<\/li>\n<li data-start=\"1258\" data-end=\"1273\">\n<p data-start=\"1260\" data-end=\"1273\">Frost melts<\/p>\n<\/li>\n<li data-start=\"1274\" data-end=\"1310\">\n<p data-start=\"1276\" data-end=\"1310\">Normal heating operation resumes<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1312\" data-end=\"1327\">During defrost:<\/p>\n<ul data-start=\"1329\" data-end=\"1457\">\n<li data-start=\"1329\" data-end=\"1383\">\n<p data-start=\"1331\" data-end=\"1383\">Heating output to the building may pause or reduce<\/p>\n<\/li>\n<li data-start=\"1384\" data-end=\"1420\">\n<p data-start=\"1386\" data-end=\"1420\">Electrical consumption continues<\/p>\n<\/li>\n<li data-start=\"1421\" data-end=\"1457\">\n<p data-start=\"1423\" data-end=\"1457\">Temporary efficiency loss occurs<\/p>\n<\/li>\n<\/ul>\n<h2 data-start=\"1464\" data-end=\"1497\"><span class=\"ez-toc-section\" id=\"How_Defrost_Affects_Efficiency\"><\/span>How Defrost Affects Efficiency<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1499\" data-end=\"1540\">Defrost cycles reduce efficiency because:<\/p>\n<ul data-start=\"1542\" data-end=\"1697\">\n<li data-start=\"1542\" data-end=\"1596\">\n<p data-start=\"1544\" data-end=\"1596\">Energy is consumed without delivering heat indoors<\/p>\n<\/li>\n<li data-start=\"1597\" data-end=\"1639\">\n<p data-start=\"1599\" data-end=\"1639\">Compressor and fans continue operating<\/p>\n<\/li>\n<li data-start=\"1640\" data-end=\"1697\">\n<p data-start=\"1642\" data-end=\"1697\">Heat may be drawn from the heating system temporarily<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1699\" data-end=\"1738\">The overall seasonal effect depends on:<\/p>\n<ul data-start=\"1740\" data-end=\"1865\">\n<li data-start=\"1740\" data-end=\"1763\">\n<p data-start=\"1742\" data-end=\"1763\">Outdoor temperature<\/p>\n<\/li>\n<li data-start=\"1764\" data-end=\"1783\">\n<p data-start=\"1766\" data-end=\"1783\">Humidity levels<\/p>\n<\/li>\n<li data-start=\"1784\" data-end=\"1799\">\n<p data-start=\"1786\" data-end=\"1799\">Coil design<\/p>\n<\/li>\n<li data-start=\"1800\" data-end=\"1820\">\n<p data-start=\"1802\" data-end=\"1820\">Control strategy<\/p>\n<\/li>\n<li data-start=\"1821\" data-end=\"1865\">\n<p data-start=\"1823\" data-end=\"1865\">Frequency and duration of defrost cycles<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"1867\" data-end=\"1951\">Defrost impact is most noticeable at temperatures slightly above and below freezing.<\/p>\n<h2 data-start=\"1958\" data-end=\"1992\"><span class=\"ez-toc-section\" id=\"Defrost_in_Standardized_Testing\"><\/span>Defrost in Standardized Testing<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1994\" data-end=\"2149\">Seasonal efficiency calculations under <strong data-start=\"2033\" data-end=\"2074\"><span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">EN 14825<\/span><\/span><\/strong> account for defrost operation within the defined climate temperature bins.<\/p>\n<p data-start=\"2151\" data-end=\"2256\">Performance data used in these calculations are measured under <strong data-start=\"2214\" data-end=\"2255\"><span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">EN 14511<\/span><\/span><\/strong>.<\/p>\n<p data-start=\"2258\" data-end=\"2401\">This ensures that standardized seasonal efficiency values such as SCOP reflect typical defrost-related losses under assumed climate conditions.<\/p>\n<h2 data-start=\"2408\" data-end=\"2446\"><span class=\"ez-toc-section\" id=\"Air-Source_vs_Ground-Source_Systems\"><\/span>Air-Source vs Ground-Source Systems<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3 data-start=\"2448\" data-end=\"2473\">Air-Source Heat Pumps<\/h3>\n<ul data-start=\"2474\" data-end=\"2560\">\n<li data-start=\"2474\" data-end=\"2500\">\n<p data-start=\"2476\" data-end=\"2500\">Exposed to outdoor air<\/p>\n<\/li>\n<li data-start=\"2501\" data-end=\"2531\">\n<p data-start=\"2503\" data-end=\"2531\">Subject to frost formation<\/p>\n<\/li>\n<li data-start=\"2532\" data-end=\"2560\">\n<p data-start=\"2534\" data-end=\"2560\">Require periodic defrost<\/p>\n<\/li>\n<\/ul>\n<h3 data-start=\"2562\" data-end=\"2590\">Ground-Source Heat Pumps<\/h3>\n<ul data-start=\"2591\" data-end=\"2694\">\n<li data-start=\"2591\" data-end=\"2623\">\n<p data-start=\"2593\" data-end=\"2623\">Use underground heat sources<\/p>\n<\/li>\n<li data-start=\"2624\" data-end=\"2658\">\n<p data-start=\"2626\" data-end=\"2658\">Operate at stable temperatures<\/p>\n<\/li>\n<li data-start=\"2659\" data-end=\"2694\">\n<p data-start=\"2661\" data-end=\"2694\">Typically not affected by frost<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2696\" data-end=\"2814\">Because ground temperatures remain above freezing, defrost impact is primarily a consideration for air-source systems.<\/p>\n<h2 data-start=\"2821\" data-end=\"2857\"><span class=\"ez-toc-section\" id=\"When_Is_Defrost_Impact_Strongest\"><\/span>When Is Defrost Impact Strongest?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"2859\" data-end=\"2890\">Defrost impact is highest when:<\/p>\n<ul data-start=\"2892\" data-end=\"3057\">\n<li data-start=\"2892\" data-end=\"2956\">\n<p data-start=\"2894\" data-end=\"2956\">Outdoor temperatures are between approximately \u20135\u00b0C and +5\u00b0C<\/p>\n<\/li>\n<li data-start=\"2957\" data-end=\"2989\">\n<p data-start=\"2959\" data-end=\"2989\">Humidity levels are elevated<\/p>\n<\/li>\n<li data-start=\"2990\" data-end=\"3057\">\n<p data-start=\"2992\" data-end=\"3057\">The heat pump operates continuously at low outdoor temperatures<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"3059\" data-end=\"3129\">At very low temperatures with dry air, frost formation may be reduced.<\/p>\n<h2 data-start=\"3136\" data-end=\"3193\"><span class=\"ez-toc-section\" id=\"Does_Defrost_Significantly_Reduce_Seasonal_Efficiency\"><\/span>Does Defrost Significantly Reduce Seasonal Efficiency?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"3195\" data-end=\"3319\">Defrost cycles reduce point efficiency during operation, but modern systems are designed to minimize duration and frequency.<\/p>\n<p data-start=\"3321\" data-end=\"3445\">Seasonal efficiency values such as SCOP already include typical defrost impact under standardized European climate profiles.<\/p>\n<p data-start=\"3447\" data-end=\"3485\">Real-world seasonal impact depends on:<\/p>\n<ul data-start=\"3487\" data-end=\"3584\">\n<li data-start=\"3487\" data-end=\"3507\">\n<p data-start=\"3489\" data-end=\"3507\">Regional climate<\/p>\n<\/li>\n<li data-start=\"3508\" data-end=\"3532\">\n<p data-start=\"3510\" data-end=\"3532\">Installation quality<\/p>\n<\/li>\n<li data-start=\"3533\" data-end=\"3557\">\n<p data-start=\"3535\" data-end=\"3557\">Control optimization<\/p>\n<\/li>\n<li data-start=\"3558\" data-end=\"3584\">\n<p data-start=\"3560\" data-end=\"3584\">Outdoor unit placement<\/p>\n<\/li>\n<\/ul>\n<h2 data-start=\"3591\" data-end=\"3632\"><span class=\"ez-toc-section\" id=\"System_Design_and_Defrost_Optimization\"><\/span>System Design and Defrost Optimization<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"3634\" data-end=\"3684\">Manufacturers improve defrost performance through:<\/p>\n<ul data-start=\"3686\" data-end=\"3819\">\n<li data-start=\"3686\" data-end=\"3717\">\n<p data-start=\"3688\" data-end=\"3717\">Advanced control algorithms<\/p>\n<\/li>\n<li data-start=\"3718\" data-end=\"3753\">\n<p data-start=\"3720\" data-end=\"3753\">Optimized heat exchanger design<\/p>\n<\/li>\n<li data-start=\"3754\" data-end=\"3784\">\n<p data-start=\"3756\" data-end=\"3784\">Variable-speed compressors<\/p>\n<\/li>\n<li data-start=\"3785\" data-end=\"3819\">\n<p data-start=\"3787\" data-end=\"3819\">Intelligent airflow management<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"4030\" data-end=\"4146\">Defrost impact refers to the temporary efficiency reduction caused by frost removal cycles in air-source heat pumps.<\/p>\n<p data-start=\"4148\" data-end=\"4151\">It:<\/p>\n<ul data-start=\"4153\" data-end=\"4358\">\n<li data-start=\"4153\" data-end=\"4205\">\n<p data-start=\"4155\" data-end=\"4205\">Occurs mainly near freezing outdoor temperatures<\/p>\n<\/li>\n<li data-start=\"4206\" data-end=\"4248\">\n<p data-start=\"4208\" data-end=\"4248\">Is automatically managed by the system<\/p>\n<\/li>\n<li data-start=\"4249\" data-end=\"4313\">\n<p data-start=\"4251\" data-end=\"4313\">Is included in standardized seasonal efficiency calculations<\/p>\n<\/li>\n<li data-start=\"4314\" data-end=\"4358\">\n<p data-start=\"4316\" data-end=\"4358\">Influences real-world winter performance<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"4360\" data-end=\"4550\">When evaluating heat pump efficiency, it is important to understand that winter efficiency varies with outdoor temperature and humidity, and defrost is a normal part of air-source operation.<\/p>\n<\/div><\/div><\/div><\/div><\/div><div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-4 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-stretch fusion-flex-justify-content-center fusion-flex-content-wrap\" style=\"max-width:1185.6px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-3 fusion-flex-column\" style=\"--awb-padding-top:1%;--awb-padding-right:2%;--awb-padding-left:2%;--awb-overflow:hidden;--awb-bg-color:#fff042;--awb-bg-color-hover:#fff042;--awb-bg-size:cover;--awb-border-radius:16px 16px 16px 16px;--awb-width-large:800px;--awb-margin-top-large:0px;--awb-spacing-right-large:2%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:2%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-title title fusion-title-3 fusion-sep-none fusion-title-center fusion-title-text fusion-title-size-paragraph blink-heading\" style=\"--awb-margin-top-small:10px;--awb-margin-right-small:0px;--awb-margin-bottom-small:10px;--awb-margin-left-small:0px;--awb-font-size:20px;\"><p class=\"fusion-title-heading title-heading-center title-heading-tag fusion-responsive-typography-calculated\" style=\"margin:0;text-transform:uppercase;font-size:1em;--fontSize:20;line-height:1.8;\"><strong>Configure your personalized heat pump system!<\/strong><\/p><\/div><div class=\"fusion-builder-row fusion-builder-row-inner fusion-row fusion-flex-align-items-stretch fusion-flex-justify-content-center fusion-flex-content-wrap\" style=\"--awb-flex-grow:0;--awb-flex-grow-medium:0;--awb-flex-grow-small:0;--awb-flex-shrink:0;--awb-flex-shrink-medium:0;--awb-flex-shrink-small:0;width:104% !important;max-width:104% !important;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-3 fusion_builder_column_inner_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:-5px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start 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Discover efficient heating, cooling, and hot water solutions for new buildings, renovations, and modern energy systems. Configure and personalize your iDM heat pump solution in just a few clicks.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-4 fusion_builder_column_inner_2_3 2_3 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:66.666666666667%;--awb-margin-top-large:0px;--awb-spacing-right-large:2.88%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:2.88%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-8\"><div style=\"display: flex; align-items: center; gap: 15px; flex-wrap: wrap;\">\n<div style=\"display: flex;\"><img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73518 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-150x150.jpg\" alt=\"Thomas Pletzer\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/thomas-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73509 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-150x150.jpg\" alt=\"Matthias Steiner\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/matthias-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73500 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-150x150.jpg\" alt=\"Christian Hutter\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/christian-hutter-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><br \/>\n<img decoding=\"async\" width=\"150\" height=\"150\" class=\"size-thumbnail wp-image-73491 aligncenter\" style=\"width: 50px; height: 50px; border-radius: 50%; border: 2px solid #000000;\" src=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-150x150.jpg\" alt=\"Adrian Egger\" srcset=\"https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-66x66.jpg 66w, https:\/\/www.idm-energie.at\/wp-content\/uploads\/2026\/07\/adrian-portrait-150x150.jpg 150w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><\/div>\n<div style=\"color: #000000; line-height: 0.7; margin-left: 2%;\"><strong style=\"display: block;\">CONNECT WITH OUR EXPERTS<\/strong><br \/>\n<span style=\"opacity: 0.8;\">50+ Years of Heat Pumps Experience<\/span><\/div>\n<\/div>\n<\/div><\/div><\/div><div class=\"fusion-layout-column fusion_builder_column_inner fusion-builder-nested-column-5 fusion_builder_column_inner_1_3 1_3 fusion-flex-column fusion-flex-align-self-center\" style=\"--awb-bg-size:cover;--awb-width-large:33.333333333333%;--awb-margin-top-large:0px;--awb-spacing-right-large:5.76%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:5.76%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\" data-scroll-devices=\"small-visibility,medium-visibility,large-visibility\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-center fusion-content-layout-column\"><div style=\"text-align:center;\"><a class=\"fusion-button button-flat fusion-button-default-size button-default fusion-button-default button-2 fusion-button-default-span fusion-button-default-type\" target=\"_self\" href=\"https:\/\/konfigurator.myidm.at\/#\/?lang=EN\" rel=\"noopener\"><span class=\"fusion-button-text awb-button__text awb-button__text--default\">Configure Now!<\/span><\/a><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"fusion-fullwidth fullwidth-box fusion-builder-row-5 fusion-flex-container has-pattern-background has-mask-background nonhundred-percent-fullwidth non-hundred-percent-height-scrolling\" style=\"--awb-border-radius-top-left:0px;--awb-border-radius-top-right:0px;--awb-border-radius-bottom-right:0px;--awb-border-radius-bottom-left:0px;--awb-flex-wrap:wrap;\" ><div class=\"fusion-builder-row fusion-row fusion-flex-align-items-flex-start fusion-flex-content-wrap\" style=\"max-width:1185.6px;margin-left: calc(-4% \/ 2 );margin-right: calc(-4% \/ 2 );\"><div class=\"fusion-layout-column fusion_builder_column fusion-builder-column-4 fusion_builder_column_1_1 1_1 fusion-flex-column\" style=\"--awb-bg-size:cover;--awb-width-large:100%;--awb-margin-top-large:0px;--awb-spacing-right-large:1.92%;--awb-margin-bottom-large:20px;--awb-spacing-left-large:1.92%;--awb-width-medium:100%;--awb-order-medium:0;--awb-spacing-right-medium:1.92%;--awb-spacing-left-medium:1.92%;--awb-width-small:100%;--awb-order-small:0;--awb-spacing-right-small:1.92%;--awb-spacing-left-small:1.92%;\"><div class=\"fusion-column-wrapper fusion-column-has-shadow fusion-flex-justify-content-flex-start fusion-content-layout-column\"><div class=\"fusion-text fusion-text-9 fusion-text-no-margin\" style=\"--awb-margin-bottom:5px;\"><h2><span class=\"ez-toc-section\" id=\"Frequently_Asked_Questions_FAQs\"><\/span>Frequently Asked Questions (FAQs)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<\/div><div class=\"accordian fusion-accordian\" style=\"--awb-border-size:1px;--awb-icon-size:16px;--awb-content-font-size:15px;--awb-icon-alignment:right;--awb-hover-color:#f9f9fb;--awb-border-color:#e2e2e2;--awb-background-color:#ffffff;--awb-divider-color:#e2e2e2;--awb-divider-hover-color:#e2e2e2;--awb-icon-color:#009fe3;--awb-title-color:#59682f;--awb-content-color:#3f3f3f;--awb-icon-box-color:#212934;--awb-toggle-hover-accent-color:#009fe3;--awb-title-font-family:&quot;Aller&quot;;--awb-title-font-weight:700;--awb-title-font-style:normal;--awb-title-font-size:18px;--awb-content-font-family:&quot;Aller&quot;;--awb-content-font-style:normal;--awb-content-font-weight:400;\"><div class=\"panel-group fusion-toggle-icon-right fusion-toggle-icon-unboxed\" id=\"accordion-67119-1\"><div class=\"fusion-panel panel-default panel-75f50f473db49b611 fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_75f50f473db49b611\"><a aria-expanded=\"false\" aria-controls=\"75f50f473db49b611\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#75f50f473db49b611\" href=\"#75f50f473db49b611\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">1. What is defrost impact in a heat pump?<\/span><\/a><\/h4><\/div><div id=\"75f50f473db49b611\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_75f50f473db49b611\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p>Defrost impact refers to the temporary reduction in heating efficiency that occurs when an air-source heat pump removes frost from its outdoor heat exchanger.<\/p>\n<p>During a defrost cycle, the system consumes electricity but may temporarily reduce or pause heat delivery to the building.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-93113629f76c244f9 fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_93113629f76c244f9\"><a aria-expanded=\"false\" aria-controls=\"93113629f76c244f9\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#93113629f76c244f9\" href=\"#93113629f76c244f9\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">2. Why do air-source heat pumps need defrost cycles?<\/span><\/a><\/h4><\/div><div id=\"93113629f76c244f9\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_93113629f76c244f9\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"642\" data-end=\"771\">When outdoor temperatures are near or below freezing and humidity is present, moisture in the air can freeze on the outdoor coil.<\/p>\n<p data-start=\"773\" data-end=\"893\">Frost buildup reduces airflow and heat transfer efficiency. A defrost cycle removes the ice to restore normal operation.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-7c7cec49dde85fe2e fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_7c7cec49dde85fe2e\"><a aria-expanded=\"false\" aria-controls=\"7c7cec49dde85fe2e\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#7c7cec49dde85fe2e\" href=\"#7c7cec49dde85fe2e\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">3. How does a defrost cycle work?<\/span><\/a><\/h4><\/div><div id=\"7c7cec49dde85fe2e\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_7c7cec49dde85fe2e\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"939\" data-end=\"992\">Most air-source heat pumps use reverse-cycle defrost.<\/p>\n<p data-start=\"994\" data-end=\"1166\">The refrigeration cycle briefly reverses, sending heat to the outdoor coil to melt accumulated frost. After the frost is removed, the system returns to normal heating mode.<\/p>\n<p data-start=\"1168\" data-end=\"1223\">This process is automatic and controlled by the system.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-cc95dcecb33a50b5c fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_cc95dcecb33a50b5c\"><a aria-expanded=\"false\" aria-controls=\"cc95dcecb33a50b5c\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#cc95dcecb33a50b5c\" href=\"#cc95dcecb33a50b5c\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">4. Does defrost significantly reduce seasonal efficiency?<\/span><\/a><\/h4><\/div><div id=\"cc95dcecb33a50b5c\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_cc95dcecb33a50b5c\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"1293\" data-end=\"1390\">Defrost cycles temporarily reduce efficiency, especially at outdoor temperatures around freezing.<\/p>\n<p data-start=\"1392\" data-end=\"1596\">However, seasonal performance values such as SCOP, calculated under <strong data-start=\"1460\" data-end=\"1501\"><span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">EN 14825<\/span><\/span><\/strong>, already account for typical defrost-related energy use under standardized climate conditions.<\/p>\n<p data-start=\"1598\" data-end=\"1665\">The overall seasonal impact depends on climate and humidity levels.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-11e55c8a967cd2d4d fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_11e55c8a967cd2d4d\"><a aria-expanded=\"false\" aria-controls=\"11e55c8a967cd2d4d\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#11e55c8a967cd2d4d\" href=\"#11e55c8a967cd2d4d\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">5. Are ground-source heat pumps affected by defrost?<\/span><\/a><\/h4><\/div><div id=\"11e55c8a967cd2d4d\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_11e55c8a967cd2d4d\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"1730\" data-end=\"1733\">No.<\/p>\n<p data-start=\"1735\" data-end=\"1918\">Ground-source systems use stable underground temperatures as a heat source and are generally not exposed to frost formation. Defrost impact primarily applies to air-source heat pumps.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-f658ab7c1fc3d309e fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_f658ab7c1fc3d309e\"><a aria-expanded=\"false\" aria-controls=\"f658ab7c1fc3d309e\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#f658ab7c1fc3d309e\" href=\"#f658ab7c1fc3d309e\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">6. When is defrost impact strongest?<\/span><\/a><\/h4><\/div><div id=\"f658ab7c1fc3d309e\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_f658ab7c1fc3d309e\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"1967\" data-end=\"2008\">Defrost impact is typically highest when:<\/p>\n<ul data-start=\"2010\" data-end=\"2111\">\n<li data-start=\"2010\" data-end=\"2074\">\n<p data-start=\"2012\" data-end=\"2074\">Outdoor temperatures are between approximately \u20135\u00b0C and +5\u00b0C<\/p>\n<\/li>\n<li data-start=\"2075\" data-end=\"2111\">\n<p data-start=\"2077\" data-end=\"2111\">Air humidity is moderate to high<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2113\" data-end=\"2186\">Under very cold and dry conditions, frost formation may be less frequent.<\/p>\n<\/div><\/div><\/div><div class=\"fusion-panel panel-default panel-f6ead8ed314544266 fusion-toggle-no-divider fusion-toggle-boxed-mode\" style=\"--awb-title-color:#59682f;--awb-content-color:#3f3f3f;\"><div class=\"panel-heading\"><h4 class=\"panel-title toggle\" id=\"toggle_f6ead8ed314544266\"><a aria-expanded=\"false\" aria-controls=\"f6ead8ed314544266\" role=\"button\" data-toggle=\"collapse\" data-parent=\"#accordion-67119-1\" data-target=\"#f6ead8ed314544266\" href=\"#f6ead8ed314544266\"><span class=\"fusion-toggle-icon-wrapper\" aria-hidden=\"true\"><i class=\"fa-fusion-box active-icon awb-icon-minus\" aria-hidden=\"true\"><\/i><i class=\"fa-fusion-box inactive-icon awb-icon-plus\" aria-hidden=\"true\"><\/i><\/span><span class=\"fusion-toggle-heading\">6. Is defrost included in standardized testing?<\/span><\/a><\/h4><\/div><div id=\"f6ead8ed314544266\" class=\"panel-collapse collapse \" aria-labelledby=\"toggle_f6ead8ed314544266\"><div class=\"panel-body toggle-content fusion-clearfix\">\n<p data-start=\"2246\" data-end=\"2250\">Yes.<\/p>\n<p data-start=\"2252\" data-end=\"2441\">Seasonal efficiency calculations use performance data measured under <strong data-start=\"2321\" data-end=\"2362\"><span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">EN 14511<\/span><\/span><\/strong> and seasonal methodology defined in <strong data-start=\"2399\" data-end=\"2440\"><span class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"><span class=\"whitespace-normal\">EN 14825<\/span><\/span><\/strong>.<\/p>\n<p data-start=\"2443\" data-end=\"2542\">These standards ensure that typical defrost operation is considered in seasonal efficiency ratings.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":34,"featured_media":2902,"parent":66448,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"100-width.php","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-67119","page","type-page","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/pages\/67119","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/users\/34"}],"replies":[{"embeddable":true,"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/comments?post=67119"}],"version-history":[{"count":0,"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/pages\/67119\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/pages\/66448"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/media\/2902"}],"wp:attachment":[{"href":"https:\/\/www.idm-energie.at\/en\/wp-json\/wp\/v2\/media?parent=67119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}