--- title: The Condenser - A Closer Look at Jamb Seals description: Minor air leaks can add up across your ductworks. That is why damper seals are important. Let's take a closer look at jamb seals for airflow dampers. image: https://newsstand.mcdlg-hvac.com/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Cover.webp --- [![MCDLG Logo (Resize)](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Logos/MCDLG%20Logo%20(Resize).webp?width=91&height=70&name=MCDLG%20Logo%20(Resize).webp)](https://mcdlg-hvac.com/) - [home](https://mcdlg-hvac.com/) - [about](https://mcdlg-hvac.com/about/) - [newsstand](https://newsstand.mcdlg-hvac.com/) - [contact](https://info.mcdlg-hvac.com/contact) - [careers](https://mcdlg-hvac.com/career-redirect/) # The Condenser - A Closer Look at Jamb Seals October 07, 2026 ![The Condenser - A Closer Look at Jamb Seals](https://newsstand.mcdlg-hvac.com/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Cover.webp) Jamb seals help minimize air leakage in the space between the blades of the damper and its jambs. Learn how these seals work with this Condenser article. Air leakage impacts your HVAC system. Even a minor leak, like air passing through a closed damper, can add up across your ductworks. That is why damper seals are important. In this Condenser, we will take a closer look at jamb seals for airflow dampers. ![MCDLG Blog 2026 - The Condenser - Jamb Seals - Closeup](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Closeup.webp?width=741&height=501&name=MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Closeup.webp) [We covered blade seals](https://newsstand.mcdlg-hvac.com/condenser-closer-look-blade-seals) before on the MCDLG Newsstand. From that article, we learned that there is a small amount of free space between damper blades when they are closed. Blade seals close these small gaps, but there are also gaps between the blades and the damper’s jambs. The size of these gaps will differ from damper to damper. Some dampers will use blades that leave wide gaps at the jambs and other dampers will have very little space. ![MCDLG Blog 2026 - The Condenser - Jamb Seals - Damper](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Damper.webp?width=539&height=501&name=MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Damper.webp) This gap is important for the damper’s blade action. Each blade needs adequate space to fully rotate without scraping against the jambs. It’s important to have full, frictionless rotation, but it also leaves an open space. When the damper closes, the jamb seals will cover the space between the jambs and the blades. They fill this space without restricting blade rotation, providing a more complete closure for the damper. These seals can be made from similar materials to blade seals, like polyurethane or vinyl. The seal needs to be pliable, so that it can close off the space without restricting the blades. ![MCDLG Blog 2026 - The Condenser - Jamb Seals - Closeup illustration](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Closeup%20illustration.webp?width=742&height=501&name=MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Closeup%20illustration.webp) Certain dampers, like [the AFD-20](https://www.arrowunited.com/Products/Details/AFD20), use a stainless-steel jamb spring. This is a thin, convex metal sheet that sits over the inside of the jamb. There are holes in the metal sheet to accommodate the damper’s axles.  The sheet will compress, like a spring, when the blades rotate. This springy design ensures that there is no friction between blades and jambs. Stainless steel jamb springs are an excellent option for jamb closure, because they provide the same benefits and don’t deteriorate over time like other types of seals. The jamb spring touches the sides of the blades when the damper is fully closed. ![MCDLG Blog 2026 - The Condenser - Jamb Seals - OpenClose2](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20OpenClose2.webp?width=676&height=501&name=MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20OpenClose2.webp) Tight closure improves system performance. Every damper counts in an efficient HVAC system, but some dampers may not have these seals. Look for blade and jamb seals when selecting airflow dampers. The damper’s submittal will list which seals come with the damper and which are optional parts. [![Click here to contact MCDLG](https://no-cache.hubspot.com/cta/default/3289606/interactive-129444095369.png)](https://newsstand.mcdlg-hvac.com/hs/cta/wi/redirect?encryptedPayload=AVxigLL7Y0lx6cpuGDMVbda1NMCjwxVFaMFiPllwcZfEJ0c7xZiX3fldVpBSLmRy3EzqBKh9A3CxFJAIlJXvyhCANSWISgJ11DlzYSJrPqLv5cwiG8lMPBo%2Fpi5IiMHPRzDPgGQmObz7qbgCs59MphTpIzMrwWRU8OoTDYDMwGzA3jyKW2cspV%2FY%2F8YNNTX8xRypt7dZqRRFDFN9ew%3D%3D&webInteractiveContentId=129444095369&portalId=3289606) #### [*next* HVAC Airflow Damper Troubleshooting Guide](https://newsstand.mcdlg-hvac.com/hvac-airflow-damper-troubleshooting-guide) [![Mestek Commercial Damper and Louver Group](https://newsstand.mcdlg-hvac.com/hs-fs/hubfs/Logos/MCDLG_Full_08302017.png?width=350&name=MCDLG_Full_08302017.png)](https://mcdlg-hvac.com/) ##### MCDLG is a collective of top-tier HVAC brands. - Arrow United Industries - Air Balance - Cesco Products - Louvers & Dampers - Airline Louvers [![Click here to contact MCDLG](https://no-cache.hubspot.com/cta/default/3289606/d92e77ed-9f51-4dab-a150-c0a00ad89871.png)](https://cta-redirect.hubspot.com/cta/redirect/3289606/d92e77ed-9f51-4dab-a150-c0a00ad89871)  We build every louver and damper from the ground up to meet your specifications. Our team works to ensure that you get the best solutions for your project's requirements. #### [![Get printed materials from MCDLG with our PDQ Portal](https://no-cache.hubspot.com/cta/default/3289606/c462dd6f-2ebe-4399-a12b-d2607190393b.png)](https://cta-redirect.hubspot.com/cta/redirect/3289606/c462dd6f-2ebe-4399-a12b-d2607190393b) #### Sign up to our PDQ Portal for printed materials from MCDLG brands. ### Subscribe to Email Updates phone (570) 746-1888 | fax (570) 746-9286 450 Riverside Drive Wyalusing, PA 18853   - [![MCDLG on Facebook](https://newsstand.mcdlg-hvac.com/hubfs/Air%20Balance%20July2017%20Sitemap/images/blog%20fb.png)](http://facebook.com/Mestek-Commercial-Damper-and-Louver-Group-1670134303245500/) - [![MCDLG on LinkedIn](https://newsstand.mcdlg-hvac.com/hubfs/Air%20Balance%20July2017%20Sitemap/images/blog%20ld.png)](https://www.linkedin.com/company/mestek-commercial-damper-and-louver-group) MCDLG is a division of Mestek Inc. ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Jess Jordan", "url" : "https://newsstand.mcdlg-hvac.com/author/jess-jordan" }, "dateModified" : "2026-10-07T15:00:00.268Z", "datePublished" : "2026-10-07T15:00:00.000Z", "headline" : "The Condenser - A Closer Look at Jamb Seals", "image" : [ "https://newsstand.mcdlg-hvac.com/hubfs/Images/Blogs/Condenser%20Articles/MCDLG%20Blog%202026%20-%20The%20Condenser%20-%20Jamb%20Seals%20-%20Cover.webp" ], "mainEntityOfPage" : { "@id" : "https://newsstand.mcdlg-hvac.com/condenser-closer-look-jamb-seals", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://newsstand.mcdlg-hvac.com/hubfs/Logos/MCDLG-logo2%20(50percent%20downscale).png" }, "name" : "Mestek Commercial Damper and Louver Group" } } ```