{"id":17570,"date":"2026-11-07T19:41:08","date_gmt":"2026-11-07T18:41:08","guid":{"rendered":"https:\/\/ventsystems.de\/lexikon\/reserve-sicherheitszuschlag\/"},"modified":"2026-11-08T08:15:17","modified_gmt":"2026-11-08T07:15:17","slug":"reserve-sicherheitszuschlag","status":"publish","type":"page","link":"https:\/\/ventsystems.de\/en\/lexikon\/reserve-sicherheitszuschlag\/","title":{"rendered":"Reserve (safety margin)"},"content":{"rendered":"<p class=\"wp-block-paragraph\">The <strong>Reserve<\/strong> (also safety margin) is the surcharge on the calculated thrust of a window actuator. It covers forces that a simple calculation does not capture: seals, friction in the hardware, wind and ageing.<\/p>\n\n\n<h2 class=\"wp-block-heading\">How much reserve is right?<\/h2>\n\n\n<ul class=\"wp-block-list\"><li><strong>+20 %:<\/strong> sheltered location, interior windows<\/li><li><strong>+30 %:<\/strong> normal case, fa\u00e7ade windows (recommended)<\/li><li><strong>+50 %:<\/strong> exposed location such as coast or tall buildings, as well as roof windows and skylights<\/li><\/ul>\n\n\n<p class=\"wp-block-paragraph\">These levels are Vent Systems guide values, not a wind load verification. Binding values are provided by the actuator manufacturer.<\/p>\n\n\n<h2 class=\"wp-block-heading\">Example<\/h2>\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"\/en\/window-actuator-calculator\/\">Window actuator calculator<\/a> gives 180 N for a fa\u00e7ade window. With 30 % reserve: 180 N \u00d7 1.3 = 234 N; the next force rating is chosen, for example a <a href=\"\/en\/product\/vs-ka\/\">VS-KA<\/a> with 250 N.<\/p>\n\n\n<h2 class=\"wp-block-heading\">Reserve or two actuators?<\/h2>\n\n\n<p class=\"wp-block-paragraph\">From a sash width of about 1.5 m, more force alone does not help: a single actuator can twist the sash. We then recommend two actuators with <a href=\"\/en\/dictionary\/synchronous-control\/\">Synchronous control<\/a>that share the force.<\/p>\n\n\n<h2 class=\"wp-block-heading\">Frequently asked questions<\/h2>\n\n\n<h3 class=\"wp-block-heading\">Can too much reserve do harm?<\/h3>\n\n\n<p class=\"wp-block-paragraph\">Not technically, but a stronger actuator costs more and is often larger. The sensible choice is the next force rating above the result including reserve.<\/p>\n\n\n<h3 class=\"wp-block-heading\">Is the snow load included in the reserve?<\/h3>\n\n\n<p class=\"wp-block-paragraph\">No. For roof windows the snow load is calculated separately and then the reserve is added on top.<\/p>\n\n\n<h2 class=\"wp-block-heading\">Read more<\/h2>\n\n\n<ul class=\"wp-block-list\"><li><a href=\"\/en\/dictionary\/thrust\/\">Glossary: Thrust force<\/a><\/li><li><a href=\"\/en\/dictionary\/glasaufbau\/\">Glossary: glazing build-up<\/a><\/li><li><a href=\"\/en\/dictionary\/tandem-operation\/\">Glossary: Tandem operation<\/a><\/li><\/ul>\n\n\n<p class=\"wp-block-paragraph\">Not sure which actuator fits? Call us at <a href=\"tel:+494050694631\">040 50694631<\/a> (Mon\u2013Fri 8 am\u20135 pm) or use the <a href=\"\/en\/drive-finder\/\">actuator finder<\/a>.<\/p>\n\n\n<p class=\"wp-block-paragraph\"><a href=\"\/en\/dictionary\/\">\u2190 Back to the glossary<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Die Reserve (auch Sicherheitszuschlag) ist der Aufschlag auf die rechnerische Schubkraft eines Fensterantriebs. Sie deckt Kr\u00e4fte ab, die eine einfache Rechnung nicht erfasst: Dichtungen, Reibung im Beschlag, Wind und Alterung. Wie viel Reserve ist richtig? +20 %: gesch\u00fctzte Lage, innenliegende Fenster +30 %: Normalfall, Fassadenfenster (empfohlen) +50 %: exponierte Lage wie K\u00fcste oder hohe Geb\u00e4ude [&hellip;]<\/p>\n","protected":false},"author":9,"featured_media":0,"parent":16230,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-17570","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/pages\/17570","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/comments?post=17570"}],"version-history":[{"count":3,"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/pages\/17570\/revisions"}],"predecessor-version":[{"id":17814,"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/pages\/17570\/revisions\/17814"}],"up":[{"embeddable":true,"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/pages\/16230"}],"wp:attachment":[{"href":"https:\/\/ventsystems.de\/en\/wp-json\/wp\/v2\/media?parent=17570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}