{"id":4649,"date":"2026-09-03T02:00:00","date_gmt":"2026-09-03T02:00:00","guid":{"rendered":"https:\/\/www.26yc.com\/ashrae-90-1-heat-recovery-requirements\/"},"modified":"2026-10-08T23:36:10","modified_gmt":"2026-10-09T06:36:10","slug":"ashrae-90-1-heat-recovery-requirements","status":"publish","type":"post","link":"https:\/\/www.26yc.com\/fr\/ashrae-90-1-heat-recovery-requirements\/","title":{"rendered":"ASHRAE 90.1 Heat Recovery Requirements"},"content":{"rendered":"<p>ASHRAE Standard 90.1 is the reference energy standard for commercial buildings in the United States, and its exhaust-air energy recovery rule is the single most common code trigger for specifying a heat recovery ventilator. This article summarizes the <strong>ASHRAE 90.1-2022<\/strong> requirements that apply to designers specifying air-to-air recovery.<\/p>\n<h2>When Recovery Is Mandatory (Section 6.5.6.1)<\/h2>\n<p>A ventilation system must include energy recovery between exhaust and outdoor air when <strong>both<\/strong> of these are true:<\/p>\n<ul>\n<li>The individual fan system design supply airflow is <strong>5,000 CFM (2.4 m&sup3;\/s)<\/strong> or greater.<\/li>\n<li>The minimum outdoor airflow is <strong>70% or more<\/strong> of the design supply airflow.<\/li>\n<\/ul>\n<p>This captures dedicated outdoor-air systems (DOAS) and densely occupied mixed-air systems. Smaller systems may still make economic sense; see the <a href=\"https:\/\/www.26yc.com\/fr\/ahu-selection-calculation\/\">AHU selection calculation<\/a> for sizing the coil and wheel together.<\/p>\n<h2>Minimum Effectiveness<\/h2>\n<table>\n<tr>\n<th>Metric<\/th>\n<th>ASHRAE 90.1-2022 requirement<\/th>\n<\/tr>\n<tr>\n<td>Minimum energy recovery ratio<\/td>\n<td>50% (enthalpy recovery ratio, per AHRI 1060)<\/td>\n<\/tr>\n<tr>\n<td>Test method<\/td>\n<td>AHRI 1060 \/ AHRI 1061<\/td>\n<\/tr>\n<tr>\n<td>Economizer bypass<\/td>\n<td>Allows bypass, but flow through device &le; 10% of design and pressure drop &le; 0.4 in. w.c.<\/td>\n<\/tr>\n<\/table>\n<p>For systems that do not provide active humidification, the sensible recovery ratio must reach 50% at the heating design condition, while the enthalpy ratio applies at the cooling design condition. The <a href=\"https:\/\/www.26yc.com\/fr\/enthalpy-recovery-vs-membrane\/\">enthalpy vs membrane comparison<\/a> helps pick the right device to clear the threshold.<\/p>\n<h2>Common Exceptions<\/h2>\n<ul>\n<li>Laboratory fume-hood exhaust and hazardous-exhaust systems.<\/li>\n<li>Commercial kitchen grease-laden exhaust.<\/li>\n<li>Dehumidification applications in humid climates where a wheel would re-introduce moisture.<\/li>\n<li>Systems where energy recovery would interfere with an air-side or water-side economizer (subject to the bypass limits above).<\/li>\n<\/ul>\n<p>When a wheel or plate core is specified, plan for the failure modes in <a href=\"https:\/\/www.26yc.com\/fr\/energy-recovery-wheel-troubleshooting\/\">energy recovery wheel troubleshooting<\/a> &mdash; frost, seal leakage, and imbalance all erode the measured effectiveness that the code assumes.<\/p>\n<h2>Why It Matters for Payback<\/h2>\n<p>Because 90.1 sets a floor, most designers specify 60&ndash;75% effectiveness to also clear <a href=\"https:\/\/www.26yc.com\/fr\/leed-energy-recovery-credit\/\">LEED energy-performance credits<\/a> and shrink cooling and heating plant. The recovery device should be selected <em>before<\/em> the coil so the DX or heating capacity is sized on the recovered load, not the raw outdoor-air load.<\/p>\n<h2>Questions fr\u00e9quemment pos\u00e9es<\/h2>\n<p><strong>When does ASHRAE 90.1-2022 require energy recovery?<\/strong><br \/>When a fan system has design supply airflow of 5,000 CFM or greater and minimum outdoor airflow of 70% or more of supply.<\/p>\n<p><strong>What minimum effectiveness does the standard require?<\/strong><br \/>A 50% energy recovery ratio, which is enthalpy per AHRI 1060, or 50% sensible at the heating design condition where no active humidification is provided.<\/p>\n<p><strong>Are there common exceptions?<\/strong><br \/>Yes, including lab fume-hood and hazardous exhaust, commercial-kitchen grease exhaust, and cases where recovery would conflict with an economizer subject to bypass limits.<\/p>\n<p><strong>How does the requirement interact with equipment selection?<\/strong><br \/>The recovery device should be selected before the coil so plant is sized on the recovered load, not the raw outdoor-air load.<\/p>\n<div class=\"yc-related\">\n<h3>Articles connexes<\/h3>\n<ul>\n<li><a href=\"https:\/\/www.26yc.com\/fr\/building-performance-standards-carbon\/\" title=\"Building Performance Standards Carbon\">Building Performance Standards Carbon<\/a><\/li>\n<\/ul>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>ASHRAE Standard 90.1 is the reference energy standard for commercial buildings in the United States, and its exhaust-air energy recovery rule is the single most common code trigger for specifying a heat recovery ventilator. This article summarizes the ASHRAE 90.1-2022 requirements that apply to designers specifying air-to-air recovery. When Recovery Is Mandatory (Section 6.5.6.1) A [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[197,241],"tags":[162,214],"class_list":["post-4649","post","type-post","status-publish","format-standard","hentry","category-encyclopedia","category-standards-codes","tag-heat-recovery","tag-standards"],"_links":{"self":[{"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/posts\/4649","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/comments?post=4649"}],"version-history":[{"count":2,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/posts\/4649\/revisions"}],"predecessor-version":[{"id":5199,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/posts\/4649\/revisions\/5199"}],"wp:attachment":[{"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/media?parent=4649"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/categories?post=4649"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.26yc.com\/fr\/wp-json\/wp\/v2\/tags?post=4649"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}