{"title":"Greenhouse Roof Vents \u0026 Automatic Openers","description":"\u003cp\u003eKeep your plants thriving year-round with the right ventilation. Excess heat, humidity, and stagnant air are among the leading causes of plant stress, mold, and disease in greenhouses, and the right roof vents, louver windows, and automatic openers are your first line of defense.\u003c\/p\u003e\n\u003ch2\u003eWhat Is Greenhouse Ventilation and Why Does It Matter?\u003c\/h2\u003e\n\u003cp\u003eProper greenhouse ventilation regulates temperature, controls humidity, and ensures a steady exchange of fresh air, all critical for healthy plant growth. Without it, summer temperatures inside a greenhouse can exceed outdoor temperatures by 30°F or more, creating conditions that scorch foliage, stress roots, and invite pests.\u003c\/p\u003e\n\u003cp\u003eRoof vents are one of the most effective greenhouse ventilation solutions because hot air naturally rises. Positioning vents at the apex of your greenhouse allows trapped heat to escape efficiently, while louver windows positioned lower on the walls draw in cooler fresh air from below, creating a natural convection current that ventilates the entire growing space.\u003c\/p\u003e\n\u003ch2\u003eRoof Vents, Louvered Windows \u0026amp; Automatic Openers: What's the Difference?\u003c\/h2\u003e\n\u003cdiv class=\"pg-feature-grid\"\u003e\n\u003cdiv class=\"pg-feature-card\"\u003e\n\u003cp\u003e\u003cstrong\u003eGreenhouse Roof Vents\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eRoof vents are installed at or near the ridge of the greenhouse roof and act as the primary exhaust point for excess heat and moisture. They are available in both manual and automatic configurations and are typically sized to match standard greenhouse roof panel widths.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"pg-feature-card\"\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/mygreenhousestore.com\/collections\/louvered-windows-for-greenhouses\" target=\"_blank\" title=\"Greenhouse Louvered Windows\" rel=\"noopener\"\u003e\u003cstrong\u003eLouvered Windows\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003eLouver windows are slatted side or end-wall vents that pivot open to admit fresh air at plant level. They work especially well alongside roof vents by creating balanced cross ventilation throughout the greenhouse.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"pg-feature-card\"\u003e\n\u003cp\u003e\u003cstrong\u003eAutomatic Vent Openers\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eAutomatic vent openers are thermostatically controlled devices that open and close greenhouse vents without electricity. Most use a heat-sensitive wax-filled cylinder that begins opening around 65–68°F and reaches full opening at approximately 77°F.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2\u003eHow Many Vents Does My Greenhouse Need?\u003c\/h2\u003e\n\u003cp\u003eAs a general guideline, greenhouse ventilation area should equal at least 15–20% of your total greenhouse floor area. For example, a 10ft x 12ft greenhouse with 120 square feet of growing space should ideally have approximately 18–24 square feet of combined ventilation area.\u003c\/p\u003e\n\u003cp\u003eUsing a combination of roof vents and louver windows helps distribute airflow more evenly while giving growers greater flexibility across changing weather conditions and growing seasons.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdetails class=\"pg-faq-item\"\u003e\n\u003csummary\u003eDo automatic greenhouse vent openers need electricity?\u003c\/summary\u003e\n\u003cdiv class=\"pg-faq-answer\"\u003e\n\u003cp\u003eNo. Most automatic vent openers operate without electricity, batteries, or wiring. They use a wax-filled piston that expands with heat and contracts as temperatures cool.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails class=\"pg-faq-item\"\u003e\n\u003csummary\u003eWhat size roof vent do I need for my greenhouse?\u003c\/summary\u003e\n\u003cdiv class=\"pg-faq-answer\"\u003e\n\u003cp\u003eVent sizing depends on your greenhouse panel width, frame design, and greenhouse size. Most roof vents are designed to replace a standard roof panel opening. Always compare vent dimensions with your greenhouse specifications before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails class=\"pg-faq-item\"\u003e\n\u003csummary\u003eCan I retrofit automatic openers onto existing roof vents?\u003c\/summary\u003e\n\u003cdiv class=\"pg-faq-answer\"\u003e\n\u003cp\u003eYes. Many automatic vent openers are designed to attach to standard greenhouse roof vent frames and are considered one of the most practical and affordable greenhouse upgrades.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails class=\"pg-faq-item\"\u003e\n\u003csummary\u003eWhat’s the difference between a ridge vent and a roof vent?\u003c\/summary\u003e\n\u003cdiv class=\"pg-faq-answer\"\u003e\n\u003cp\u003eA ridge vent runs continuously along the roof peak for maximum passive airflow, while individual roof vents are separate vent panels that open and close independently. For most hobby and mid-size greenhouses, individual automatic roof vents are the more practical and economical solution.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eShop our full range of greenhouse roof vents, louver windows, automatic openers, restraint wires, and greenhouse ventilation accessories below. These products are designed for easy installation, dependable climate control, and compatibility with many of today’s most popular greenhouse brands and frame systems.\u003c\/p\u003e","products":[{"product_id":"canopia-roof-vent-for-canopia-hobby-grand-prestige-greenhouses","title":"Palram - Canopia | Roof Vent for Palram - Canopia Hobby\/Grand\/Prestige Greenhouses","description":"\u003cp\u003eIncrease the air circulation in your Rion Hobby Gardener 2, Grand Gardener 2 or Prestige 2 greenhouse with an additional air vent. Additional air vents will reduce humidity and improve air circulation to keep your greenhouse cooler on warm days.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eProvides additional air ventilation\u003c\/li\u003e\n\u003cli\u003eIncreases circulation when paired with the Side Louver Window\u003c\/li\u003e\n\u003cli\u003eHelps regulate temperatures\u003c\/li\u003e\n\u003cli\u003eManual adjustment for variable airflow\u003c\/li\u003e\n\u003cli\u003eWorks with all Rion Hobby Gardener 2, Grand Gardener 2 or Prestige 2 greenhouse\u003c\/li\u003e\n\u003cli\u003eCan be fitted with the Rion Automatic Roof Vent Opener for optimal airflow\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Palram - Canopia","offers":[{"title":"Default Title","offer_id":40735506006165,"sku":"HG1031","price":118.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/products\/palram-canopia-greenhouse-accessories-palram-canopia-roof-vent-for-palram-canopia-hobby-grand-prestige-greenhouses-hg1031-31598323597461.jpg?v=1751051045"},{"product_id":"canopia-automatic-roof-vent-opener-for-rion-greenhouses","title":"Palram - Canopia | Automatic Roof Vent Opener for Palram - Canopia Greenhouses and Sunrooms","description":"\u003cp\u003eThe Automatic Vent Opener was designed to automatically control the temperature in all Palram - Canopia Greenhouses, and the Sun Room Six and Sun Room Eight. As the air inside the greenhouse warms, the vent gradually opens to allow the correct amount of airflow into the greenhouse and closes when the optimal temperature is reached. The vent arm was designed with the use of natural wax that expands as the air gets warmer, to push a piston which raises the window, then contracts as it cools, closing with the use of a spring. The Automatic Vent Opener operates without the use of electricity.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAssembled dimension: 11\" W x 2\" D x 2\" H\u003c\/li\u003e\n\u003cli\u003eAutomatically control ventilation\u003c\/li\u003e\n\u003cli\u003eProtect your plants from heat exposure\u003c\/li\u003e\n\u003cli\u003eProvides gradual airflow - opens more the hotter it gets. You can adjust the temperature that the opener begins to activate over approximately a 5-degree range.\u003c\/li\u003e\n\u003cli\u003eEasy to install\u003c\/li\u003e\n\u003cli\u003eWorks with Palram - Canopia \u003cstrong\u003ePrestige\u003c\/strong\u003e, \u003cstrong\u003eGrand Gardener\u003c\/strong\u003e, \u003cstrong\u003eEco Grow\u003c\/strong\u003e, and \u003cstrong\u003eHobby Gardener\u003c\/strong\u003e greenhouses\u003c\/li\u003e\n\u003cli\u003eWorks with Palram - Canopia \u003cstrong\u003eSun Room Six\u003c\/strong\u003e and \u003cstrong\u003eSun Room Eight\u003c\/strong\u003e lean to sunrooms\u003c\/li\u003e\n\u003cli\u003eHeat activated, no electricity necessary, adjustable temperature range\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Palram - Canopia","offers":[{"title":"Default Title","offer_id":40735508758677,"sku":"HG1027","price":88.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/products\/palram-canopia-greenhouse-accessories-palram-canopia-automatic-roof-vent-opener-for-palram-canopia-greenhouses-hg1027-31598327365781.jpg?v=1751051041"},{"product_id":"canopia-automatic-roof-vent-opener-for-canopia-greenhouses","title":"Palram - Canopia | Automatic Roof Vent Opener for Palram - Canopia Greenhouses","description":"\u003cp\u003eThe Automatic Vent Opener was designed to automatically control the temperature in all Palram - Canopia Greenhouses. As the air inside the greenhouse warms, the vent gradually opens to allow the correct amount of airflow into the greenhouse and closes when the optimal temperature is reached. The vent arm was designed with the use of natural wax that expands to push a piston, which raises the window, as the air gets warmer then contracts as it cools, closing with the use of a spring. The Automatic Vent Opener operates without the use of electricity.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eOpens roof vent window automatically around 68°F for air circulation, closes when the temperature cools.  Opens gradually as the temperature rises.  The operating temperature is slightly adjustable.\u003c\/li\u003e\n\u003cli\u003eDurable metal design with natural wax\u003c\/li\u003e\n\u003cli\u003eSmart-Lock connectors make installation quick and easy\u003c\/li\u003e\n\u003cli\u003eWorks with Palram - Canopia Nature Series (\u003cstrong\u003eMythos\u003c\/strong\u003e, \u003cstrong\u003eHybrid\u003c\/strong\u003e, \u003cstrong\u003eEssence\u003c\/strong\u003e), \u003cstrong\u003eSnap \u0026amp; Grow\u003c\/strong\u003e, \u003cstrong\u003eGlory\u003c\/strong\u003e, \u003cstrong\u003eAmericana\u003c\/strong\u003e, and \u003cstrong\u003eChalet\u003c\/strong\u003e greenhouses\u003c\/li\u003e\n\u003cli\u003eWindow is not included\u003c\/li\u003e\n\u003cli\u003e1 Year Limited Warranty\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Palram - Canopia","offers":[{"title":"Default Title","offer_id":40735512854677,"sku":"HG1005","price":109.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/products\/palram-canopia-greenhouse-accessories-palram-canopia-automatic-roof-vent-opener-for-palram-canopia-greenhouses-hg1005-31598336934037.jpg?v=1751051027"},{"product_id":"palram_canopia_vent_kit_for_mythos_hybrid_americana_essence_and_balance_greenhouses","title":"Palram - Canopia | Vent Kit for Mythos, Hybrid, Americana, Essence and Balance Greenhouses","description":"\n\u003cp\u003eIncrease the air circulation in your Mythos, Hybrid, Americana or Essence model greenhouse with an additional air vent. Additional air vents will reduce humidity and improve air circulation to keep your greenhouse cooler on warm days.\u003c\/p\u003e\n\u003ch6\u003eFEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003eProvides additional air ventilation\u003c\/li\u003e\n\u003cli\u003eIncreases circulation when paired with the Side Louver Window\u003c\/li\u003e\n\u003cli\u003eHelps regulate temperatures\u003c\/li\u003e\n\u003cli\u003eManual adjustment for variable airflow\u003c\/li\u003e\n\u003cli\u003eWorks with all Silver Mythos and Hybrid greenhouses as well as Americana and Essence models\u003c\/li\u003e\n\u003cli\u003eCan be fitted with the Automatic Louver Window Opener for optimal airflow\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e1 Year Limited Warranty\u003c\/p\u003e","brand":"Palram - Canopia","offers":[{"title":"Default Title","offer_id":42550880600213,"sku":"HG1013","price":60.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/products\/palram-canopia-greenhouse-accessories-palram-canopia-vent-kit-for-mythos-hybrid-americana-essence-and-balance-greenhouses-hg1013-35191501553813.jpg?v=1751050693"},{"product_id":"janssens-roof-window-fly-screen","title":"Janssens | Roof Window Fly Screen for Greenhouses","description":"\u003cp\u003eKeep fresh air flowing while helping keep insects out. The \u003cstrong\u003eJanssens Roof Window Fly Screen\u003c\/strong\u003e is a practical upgrade designed for Janssens greenhouse roof vents, giving you better ventilation comfort without inviting unwanted bugs into your growing space.\u003c\/p\u003e\n\u003cp\u003eThis factory-assembled screen mounts underneath the roof window and includes a built-in slot with a brush seal opening for the window operating device, so your vent can continue to function smoothly.\u003c\/p\u003e\n\u003ch3\u003eWhy Choose the Janssens Roof Window Fly Screen?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eHelps keep insects out while allowing fresh air in\u003c\/li\u003e\n\u003cli\u003eDesigned to fit Janssens greenhouse roof vents\u003c\/li\u003e\n\u003cli\u003eFactory assembled for quick and easy installation\u003c\/li\u003e\n\u003cli\u003eBuilt-in brush-sealed slot supports window opener operation\u003c\/li\u003e\n\u003cli\u003eDurable aluminum frame for long-lasting performance\u003c\/li\u003e\n\u003cli\u003eMade in Belgium by Janssens\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e Black\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 28 7\/16” x 31 7\/16”\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFrame Material:\u003c\/strong\u003e Aluminum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation:\u003c\/strong\u003e Factory assembled, only needs to be inserted\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting Location:\u003c\/strong\u003e Underneath the roof window\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecial Design:\u003c\/strong\u003e Includes slot\/brush seal opening for the window operating device\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCountry of Manufacture:\u003c\/strong\u003e Belgium\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eIdeal For\u003c\/h3\u003e\n\u003cp\u003eThis greenhouse roof vent fly screen is ideal for gardeners who want to improve airflow in their Janssens greenhouse while reducing the chance of flying insects entering through the roof vent.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eWhat is the Janssens Roof Window Fly Screen used for?\u003c\/h4\u003e\n\u003cp\u003eIt is used to help keep insects out of your greenhouse while allowing ventilation through the roof window.\u003c\/p\u003e\n\u003ch4\u003eIs this fly screen compatible with Janssens greenhouses?\u003c\/h4\u003e\n\u003cp\u003eYes. It is designed specifically as an optional addition for a Janssens greenhouse roof vent.\u003c\/p\u003e\n\u003ch4\u003eDoes the fly screen work with the roof window opener?\u003c\/h4\u003e\n\u003cp\u003eYes. It includes a slot with a brush seal opening that allows the window operating device to function properly.\u003c\/p\u003e\n\u003ch4\u003eIs installation difficult?\u003c\/h4\u003e\n\u003cp\u003eNo. The fly screen is factory assembled and designed for easy insertion beneath the roof window.\u003c\/p\u003e\n\u003ch4\u003eWhat colors are available?\u003c\/h4\u003e\n\u003cp\u003eThis fly screen is stocked in Black. \u003cspan\u003eThey can be special ordered in other colors if needed - call us at 888-648-5333.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003eWarranty and Financing\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWarranty:\u003c\/strong\u003e 15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinancing:\u003c\/strong\u003e Financing Available\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Jannsens Retro Victorian Greenhouse Warranty MyGreenhouseStore\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/2022-Victorian-greenhouse-warranty-_originated-Jan-2017.pdf\" target=\"_blank\"\u003e\u003cimg width=\"250\" style=\"border: 1px solid #bdbdbd;\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Jannsens_Retro_Victorian_Greenhouse_Warranty_MyGreenhouseStore.jpg\"\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"Janssens","offers":[{"title":"Black","offer_id":44472345002133,"sku":"VI-FLY-ROOF-WINDOW-BLACK","price":310.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Janssens-Roof-Window-Fly-Screen-1.jpg?v=1751049997"},{"product_id":"hoklartherm-riga-roof-vent-opener","title":"Hoklartherm | Riga Automatic Roof Vent Opener","description":"\u003cp\u003eRIGA Automatic Window Opener (no electricity needed) with quick release arm - allows the opener to be disconnected in adverse weather conditions. \u003c\/p\u003e\n\u003cdiv class=\"page\" title=\"Page 1\"\u003e\n\u003cdiv class=\"layoutArea\"\u003e\n\u003cdiv class=\"column\"\u003e\n\u003cp\u003e\u003cspan\u003eThe black piston cylinder is filled with a mix of oils that naturally expand around 73 degrees. As the oil expands, it will begin to push out the rod of the piston and open your window. The springs and the weight of the window will pull the window shut when the temperature drops. \u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003ciframe title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/c1puKg73kmg?si=FAVpJfJiKDSbJjPI\" height=\"315\" width=\"560\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003cul\u003e\u003c\/ul\u003e","brand":"Hoklartherm","offers":[{"title":"Default Title","offer_id":45030640353429,"sku":"RIGA-AUTO-OPENER","price":150.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Hoklartherm-roof-Window-opener.jpg?v=1751049962"},{"product_id":"janssens-automatic-opener-for-push-open-side-window-or-roof-window","title":"Janssens | Automatic Opener for Push Open Side Window or Roof Window","description":"\n\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003eJanssens Automatic Opener for Push Open or Roof Window \u003c\/strong\u003eis an optional addition to your Push Open or Roof window in your Janssens greenhouse.  T\u003c\/span\u003ehe black tube is filled with special paraffin oil which expands when the temperature reaches around 72º F and the piston will push the window open. When temperature falls a heavy spring pulls the window closed. \u003cstrong\u003eNo electricity needed!\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Jannsens Retro Victorian Greenhouse Warranty MyGreenhouseStore\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/2022-Victorian-greenhouse-warranty-_originated-Jan-2017.pdf\" target=\"_blank\"\u003e\u003cimg width=\"250\" style=\"border: 1px solid #bdbdbd;\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Jannsens_Retro_Victorian_Greenhouse_Warranty_MyGreenhouseStore.jpg\"\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"Janssens","offers":[{"title":"Default Title","offer_id":45104282861717,"sku":"VI-RO-AUTO-OPENER","price":124.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Janssens-auto-opener-janssens-1.jpg?v=1772223307"},{"product_id":"janssens-greenhouse-roof-window","title":"Janssens | Greenhouse Roof Vent","description":"\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003eJanssens Greenhouse Roof Vent\u003c\/strong\u003e can be added to any Royal Victorian or Cathedral kit at the time of order.  These come in \u003c\/span\u003e\u003cspan\u003eBlack or Dark Green.  \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eMost Royal Victorian and Cathedral models already include at least one roof vent.  You can add as many roof vents as you want to your greenhouse with the caveat that you cannot put the vents adjacent to each other - so 'every other panel' would be the most you can add.  Auto-openers and fly screens are available.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch6\u003eFEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003eColor: Black or Green\n\u003cul\u003e\n\u003cli\u003eCustom colors can be ordered (e.g. when ordering a greenhouse in a custom color), call us at 888-648-5333\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eFrame Material: Aluminum\u003c\/li\u003e\n\u003cli\u003eManual Operation\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/mygreenhousestore.com\/products\/janssens-automatic-opener-for-louvered-window\" title=\"Auto-Opener For Roof Window\" rel=\"noopener\" target=\"_blank\"\u003eAuto-opener (heat operated) available here\u003c\/a\u003e\u003ca href=\"https:\/\/mygreenhousestore.com\/products\/janssens-louvered-window-lexan-cover\" title=\"Lexan Cover for Louvered Window\" rel=\"noopener\" target=\"_blank\"\u003e\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/mygreenhousestore.com\/products\/janssens-louvered-window-fly-screen\" title=\"Roof Window Fly Screen\" rel=\"noopener\" target=\"_blank\"\u003eFly Screen available here\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003eMade in Belgium by Janssens\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e15 Year Limited Warranty\u003c\/li\u003e\n\u003cli\u003eFinancing Available\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/2022-Victorian-greenhouse-warranty-_originated-Jan-2017.pdf\" title=\"Jannsens Retro Victorian Greenhouse Warranty MyGreenhouseStore\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Jannsens_Retro_Victorian_Greenhouse_Warranty_MyGreenhouseStore.jpg\" style=\"border: 1px solid #bdbdbd;\" width=\"250\"\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"Janssens","offers":[{"title":"Black \/ Royal Victorian","offer_id":45142613000341,"sku":"VI-RW-B","price":419.0,"currency_code":"USD","in_stock":true},{"title":"Black \/ Cathedral (Special Order)","offer_id":45142623027349,"sku":"CUSTOM-RW-CATHEDRAL-B","price":450.0,"currency_code":"USD","in_stock":true},{"title":"Green \/ Royal Victorian","offer_id":45142613033109,"sku":"VI-RW-G","price":419.0,"currency_code":"USD","in_stock":true},{"title":"Green \/ Cathedral (Special Order)","offer_id":45142623060117,"sku":"CUSTOM-RW-CATHEDRAL-G","price":450.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Janssens-Victorian-roof-vent-2.jpg?v=1751049954"},{"product_id":"alton-greenhouse-roof-vent-with-automatic-opener","title":"Alton | Greenhouse Roof Vent With Automatic Opener","description":"\u003cp\u003eEnhance the functionality of your Alton greenhouse with the \u003cstrong\u003eAlton Greenhouse Roof Vent with Automatic Opener\u003c\/strong\u003e. Designed for effortless ventilation, this innovative accessory helps maintain optimal growing conditions by automatically regulating temperature and airflow in your greenhouse.\u003c\/p\u003e\n\u003ch4\u003e\u003cstrong\u003eKey Features:\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003e\u003cstrong\u003eAutomatic Temperature Control\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEquipped with an advanced automatic opener that reacts to temperature changes.\u003c\/li\u003e\n\u003cli\u003eOpens and closes the vent seamlessly to ensure your plants stay cool in warm weather and protected when temperatures drop.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eEfficient Airflow Management\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eImproves ventilation, reducing humidity and preventing overheating in your greenhouse.\u003c\/li\u003e\n\u003cli\u003eEnsures a healthy environment for your plants by promoting consistent air circulation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eDurable and Weather-Resistant Design\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eBuilt with high-quality materials to withstand various weather conditions.\u003c\/li\u003e\n\u003cli\u003eDesigned specifically for Alton greenhouses, ensuring a perfect fit and long-lasting performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eEasy to Install and Maintain\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSimple to attach to your existing Alton greenhouse roof frame.\u003c\/li\u003e\n\u003cli\u003eMinimal maintenance required for reliable, year-round operation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003e\u003cstrong\u003eWhy Choose the Alton Greenhouse Roof Vent with Automatic Opener?\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHands-Free Convenience:\u003c\/strong\u003e No need to manually adjust the vent—focus on your gardening while the opener handles temperature regulation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptimal Growing Environment:\u003c\/strong\u003e Protects your plants from heat stress and excessive humidity, fostering healthier growth.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeamless Compatibility:\u003c\/strong\u003e Made to integrate perfectly with your Alton greenhouse, combining functionality with style.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eUpgrade your greenhouse today with the \u003cstrong\u003eAlton Greenhouse Roof Vent with Automatic Opener\u003c\/strong\u003e for an effortless way to create the perfect growing conditions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eOrder now\u003c\/strong\u003e and give your plants the care they deserve!\u003c\/p\u003e\n\u003cp\u003eNote: this item is only available to order with the purchase of an Alton Greenhouse.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":45644239437973,"sku":"ALT-ROOFVENT-4251","price":350.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Alton_Westminster_Cedar_Greenhouse-MyGreenhouseStore-6.jpg?v=1751049926"},{"product_id":"janssens-spindle-opener-for-roof-window","title":"Janssens | Spindle Opener for Roof Window","description":"\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003eJanssens Spindle Opener for Roof Window \u003c\/strong\u003eis an optional addition to your Roof window in your Janssens greenhouse.  This is a manual opener that works like a large threaded screw - for Royal or Junior Victorians.  Very strong and heavy duty - good for high wind areas - \u003cstrong\u003elong handle NOT included.\u003c\/strong\u003e  If you already have a spindle opener, you should already have the handle.  If not, you can order the Long Handle for Spindle Opener here.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Jannsens Retro Victorian Greenhouse Warranty MyGreenhouseStore\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/2022-Victorian-greenhouse-warranty-_originated-Jan-2017.pdf\" target=\"_blank\"\u003e\u003cimg width=\"250\" style=\"border: 1px solid #bdbdbd;\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Jannsens_Retro_Victorian_Greenhouse_Warranty_MyGreenhouseStore.jpg\"\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"Janssens","offers":[{"title":"Default Title","offer_id":46249439264917,"sku":"VI-SPINDLE","price":169.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Janssens-spindle-roof-window-opener_c2ceac93-8b97-4216-a87c-9f2a91504488.jpg?v=1772223566"},{"product_id":"janssens-long-handle-for-spindle-opener","title":"Janssens | Long Handle for Spindle Opener","description":"\u003cp\u003e\u003cstrong\u003eLong Handle for Spindle Opener\u003c\/strong\u003e -  5 feet long  - note: if you are buying a Spindle Opener for your greenhouse (and you don't already have a handle) you ALSO need to buy this handle.\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003e15 Year Limited Warranty\u003c\/p\u003e\n\u003cp\u003e\u003ca title=\"Jannsens Retro Victorian Greenhouse Warranty MyGreenhouseStore\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/2022-Victorian-greenhouse-warranty-_originated-Jan-2017.pdf\" target=\"_blank\"\u003e\u003cimg width=\"250\" style=\"border: 1px solid #bdbdbd;\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Jannsens_Retro_Victorian_Greenhouse_Warranty_MyGreenhouseStore.jpg\"\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"Janssens","offers":[{"title":"Default Title","offer_id":46249443459221,"sku":"VI-HANDLE-SPINDLE","price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/JanssensLongHandleforSpindleOpener.jpg?v=1772223624"},{"product_id":"vego-auto-vent-opener-2-pack","title":"Vego | Greenhouse Roof Vent Auto Opener - 2 Pack","description":"\u003cdiv class=\"mgs-product-copy\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eVego greenhoue roof vent auto opener\u003c\/strong\u003e helps your greenhouse regulate airflow automatically without electricity, wiring, or daily adjustments. As temperatures rise, the hydraulic cylinder gradually opens the roof vent to release excess heat. As temperatures cool, the vent slowly closes to help retain warmth and stabilize the growing environment.\u003c\/p\u003e\n\u003cp\u003eFor many greenhouse growers, ventilation quickly becomes one of the most important upgrades after installation. Excess heat buildup can stress plants, reduce productivity, and create inconsistent growing conditions. This automatic roof vent opener helps maintain healthier airflow while reducing the need for constant manual monitoring, and helps create a more stable greenhouse climate throughout the growing season.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eA simple “set it and forget it” upgrade for Vego greenhouse owners who want better airflow, healthier plants, and greater peace of mind.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch6\u003eKEY FEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomatic temperature control:\u003c\/strong\u003e Opens between 60°F and 77°F to help prevent greenhouse overheating\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo electricity required:\u003c\/strong\u003e Fully mechanical hydraulic operation with no wiring or batteries\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImproves greenhouse airflow:\u003c\/strong\u003e Helps reduce trapped heat and humidity buildup\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUp to 18in vent opening:\u003c\/strong\u003e Creates stronger passive ventilation during warm weather\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual spring support system:\u003c\/strong\u003e Provides added lifting strength and stability\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurable outdoor construction:\u003c\/strong\u003e Powder-coated aluminum frame with stainless steel springs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdjustable operation:\u003c\/strong\u003e Fine-tune vent opening and response temperature\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow-maintenance solution:\u003c\/strong\u003e Designed for long-term greenhouse use with minimal upkeep\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch6\u003eSPECIFICATIONS\u003c\/h6\u003e\n\n\u003cdiv class=\"pg-spec-grid\"\u003e\n\n  \u003cdiv class=\"pg-spec-card\"\u003e\n    \u003cp\u003e\u003cstrong\u003ePRODUCT TYPE\u003c\/strong\u003e\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eAccessory:\u003c\/strong\u003e Automatic roof vent opener\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003ePack Size:\u003c\/strong\u003e 2 openers\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eOperation:\u003c\/strong\u003e Mechanical hydraulic system\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003ePower Requirement:\u003c\/strong\u003e None\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"pg-spec-card\"\u003e\n    \u003cp\u003e\u003cstrong\u003eTEMPERATURE PERFORMANCE\u003c\/strong\u003e\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eWorking Temperature Range:\u003c\/strong\u003e 50°F to 122°F\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eVent Opening Starts:\u003c\/strong\u003e 60°F to 77°F\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eFully Open By:\u003c\/strong\u003e Approximately 100°F\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"pg-spec-card\"\u003e\n    \u003cp\u003e\u003cstrong\u003eVENT PERFORMANCE\u003c\/strong\u003e\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eMaximum Vent Opening:\u003c\/strong\u003e 18in\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eLift Capacity:\u003c\/strong\u003e Up to 15 lbs\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eAdjustment:\u003c\/strong\u003e Adjustable cylinder tension\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"pg-spec-card\"\u003e\n    \u003cp\u003e\u003cstrong\u003eMATERIALS\u003c\/strong\u003e\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eFrame:\u003c\/strong\u003e Powder-coated aluminum alloy\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eSprings:\u003c\/strong\u003e Stainless steel dual springs\u003c\/p\u003e\n    \u003cp\u003e\u003cstrong\u003eCylinder:\u003c\/strong\u003e Hydraulic temperature-sensitive cylinder\u003c\/p\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e  \n\n\u003ch6\u003eWHAT'RE INCLUDED\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e2 Auto vent opener assemblies\u003c\/li\u003e\n\u003cli\u003e2 Hydraulic cylinders\u003c\/li\u003e\n\u003cli\u003e2 Stop pins\u003c\/li\u003e\n\u003cli\u003e2 Hair pins\u003c\/li\u003e\n\u003cli\u003eMounting screws and installation hardware\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eINSTALLATION GUIDE\u003c\/h6\u003e\n\u003cp\u003eThe Vego Auto Vent Opener installs directly onto compatible greenhouse roof vents using basic hand tools.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eThread the cylinder into the opener assembly before installation\u003c\/li\u003e\n\u003cli\u003eFor easier setup, chill the cylinder for 15 to 20 minutes before adjustment\u003c\/li\u003e\n\u003cli\u003eInstall while the roof vent is fully closed\u003c\/li\u003e\n\u003cli\u003eSecure the mounting brackets to the greenhouse frame and roof vent\u003c\/li\u003e\n\u003cli\u003eAdjust the cylinder tension after installation for preferred vent opening performance\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0286\/2271\/6963\/files\/Manual_for_Auto_Vent_Opener_A4_05-06-2025.pdf?v=1757320896\" target=\"_blank\" title=\"Vego Greenhouse Roof Vent Auto Opener\" rel=\"noopener\"\u003eView Installation Manual\u003c\/a\u003e\u003c\/p\u003e\n\u003ch6\u003eMAINTENANCE AND CARE\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003eInspect the hydraulic cylinder every 6 to 12 months\u003c\/li\u003e\n\u003cli\u003eLubricate moving components with light machine oil as needed\u003c\/li\u003e\n\u003cli\u003eDo not disassemble the cylinder\u003c\/li\u003e\n\u003cli\u003eRemove or store indoors during freezing weather conditions\u003c\/li\u003e\n\u003cli\u003eBefore reinstalling, confirm that the piston rod moves smoothly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eOPTIONAL ACCESSORIES\u003c\/h6\u003e\n\u003cp\u003eMany greenhouse owners combine automatic vent openers with additional climate-control accessories to create a more productive growing environment.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eGreenhouse shade cloth systems for summer heat reduction\u003c\/li\u003e\n\u003cli\u003eCirculation fans for improved airflow consistency\u003c\/li\u003e\n\u003cli\u003eGreenhouse shelving and grow systems\u003c\/li\u003e\n\u003cli\u003eRaised garden beds and seed-starting systems\u003c\/li\u003e\n\u003cli\u003eAdditional roof vents and ventilation accessories\u003c\/li\u003e\n\u003cli\u003eGreenhouse thermometers and environmental monitoring tools\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePopular pairing:\u003c\/strong\u003e Vego greenhouse owners often add automatic vent openers alongside greenhouse shade systems to help maintain more stable growing temperatures during warmer months.\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003eThe Vego Auto Vent Opener includes a 1-year manufacturer warranty.\u003c\/p\u003e\n\u003ch6\u003eMANUFACTURER INFO AND UNIQUE SELLING POSITION\u003c\/h6\u003e\n\u003cp\u003eVego Garden is known for combining practical functionality with modern garden design. Their greenhouse accessories are designed to help home growers create more productive and easier-to-manage growing spaces.\u003c\/p\u003e\n\u003cp\u003eThe Vego Auto Vent Opener offers one of the simplest and most effective greenhouse climate-control upgrades available. By automatically responding to temperature changes, it helps reduce heat stress, improve airflow, and support healthier plant growth without adding electrical complexity or ongoing maintenance.\u003c\/p\u003e\n\u003cp\u003eFor greenhouse owners who cannot constantly monitor temperatures throughout the day, automatic roof ventilation can make a meaningful difference in growing performance and plant protection.\u003c\/p\u003e\n\u003ch6\u003eFREQUENTLY ASKED QUESTIONS\u003c\/h6\u003e\n\u003cp\u003e\u003cstrong\u003eHow does the Vego Auto Vent Opener work?\u003c\/strong\u003e\u003cbr\u003eThe hydraulic cylinder expands as temperatures rise, automatically opening the roof vent. As temperatures cool, the cylinder contracts and closes the vent.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes this vent opener require electricity?\u003c\/strong\u003e\u003cbr\u003eNo. It operates mechanically without electricity, batteries, or solar power.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhen does the vent start opening?\u003c\/strong\u003e\u003cbr\u003eThe vent typically begins opening between 60°F and 77°F.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow far can the vent open?\u003c\/strong\u003e\u003cbr\u003eThe opener can lift the vent up to 18 inches.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is the lifting capacity?\u003c\/strong\u003e\u003cbr\u003eThe unit can lift vents weighing up to 15 lbs.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan the opening range be adjusted?\u003c\/strong\u003e\u003cbr\u003eYes. The cylinder tension can be adjusted to fine-tune vent opening performance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this compatible with all greenhouses?\u003c\/strong\u003e\u003cbr\u003eIt fits most greenhouse roof windows, including Vego greenhouse systems and many compatible greenhouse designs.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eShould I remove the opener during winter?\u003c\/strong\u003e\u003cbr\u003eYes. During freezing temperatures, it is recommended to remove or store the cylinder indoors to help protect long-term performance.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Vego Garden","offers":[{"title":"Black","offer_id":47354794049685,"sku":"VGHAVO2P","price":99.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Vego-auto-vent-opener005.png?v=1779135143"},{"product_id":"alton-thermofor-classic-roof-vent-auto-opener","title":"Alton | Thermofor Classic Roof Vent Auto Opener","description":"\u003cp\u003eThe Thermofor Classic Roof Auto Opener is a simple, reliable way to keep your Alton greenhouse properly ventilated, without any manual effort. Designed specifically for Alton greenhoue roof vents, it uses a heat-sensitive, oil-filled piston that automatically opens the vent as temperatures rise, helping create a healthier growing environment for your plants.\u003c\/p\u003e\n\u003cp\u003eAs the greenhouse warms, the piston expands and gently lifts the vent. When temperatures cool, the vent closes on its own. You can easily adjust the opening range between 59°F and 77°F to match your growing conditions. The piston is included and ready to install.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAutomatically opens your roof vent as the greenhouse heats up\u003c\/li\u003e\n\u003cli\u003eHelps protect plants from overheating by improving airflow\u003c\/li\u003e\n\u003cli\u003eNo electricity or batteries needed, fully powered by temperature changes\u003c\/li\u003e\n\u003cli\u003eEasy to install, compatible with most aluminum and wooden greenhouses, clamps onto many aluminum frames\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAdding an auto opener is one of the easiest ways to stabilize greenhouse temperatures and get the most out of your roof ventilation. It works quietly in the background, responding naturally to heat, so your plants stay comfortable even when you’re not around.\u003c\/p\u003e\n\u003cp\u003eThe operating temperature can be adjusted to suit seasonal needs or specific plant requirements.\u003c\/p\u003e\n\u003cp\u003eBacked by a two-year warranty for added peace of mind.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":47355022672021,"sku":"ALTTHAUTO","price":150.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/thermofor-roof-vent-opener.jpg?v=1778811597"},{"product_id":"alton-bayliss-xl-roof-vent-auto-opener","title":"Alton | Bayliss XL Roof Vent Auto Opener","description":"\u003cp\u003eThe \u003cstrong\u003eBayliss Clip-On Automatic Greenhouse Vent Opener\u003c\/strong\u003e is a simple, reliable solution for maintaining the ideal temperature inside your greenhouse, without constant monitoring. Designed for convenience and performance, this unit automatically opens and closes your roof vent based on temperature changes, helping protect your plants from overheating.\u003c\/p\u003e\n\u003cp\u003eBuilt to lift up to 12 lbs (5.5 kg), this auto vent opener provides a maximum opening of approximately 12 inches, allowing consistent airflow when your greenhouse needs it most. Its compact 11-inch design and satin anodized finish deliver both durability and a clean, professional look that complements most greenhouse frames.\u003c\/p\u003e\n\u003ch6\u003eKEY FEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eClip-on design:\u003c\/strong\u003e Quick, hassle-free installation on compatible greenhouse vents.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12 lb lifting capacity:\u003c\/strong\u003e Supports vent loads up to 12 lbs (5.5 kg).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12-inch maximum opening:\u003c\/strong\u003e Helps release excess heat and improve airflow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo electricity required:\u003c\/strong\u003e Powered entirely by heat expansion.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSatin anodized finish:\u003c\/strong\u003e Durable, clean, and professional appearance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eSPECIFICATIONS\u003c\/h6\u003e\n\u003cdiv style=\"background-color: #f4f8f2; padding: 18px; border-radius: 12px; margin: 14px 0;\"\u003e\n\u003cp\u003e\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Automatic greenhouse vent opener\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation Style:\u003c\/strong\u003e Clip-on\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaximum Vent Opening:\u003c\/strong\u003e Approximately 12 inches\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaximum Lifting Capacity:\u003c\/strong\u003e 12 lbs (5.5 kg)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eUnit Length:\u003c\/strong\u003e 11 inches\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinish:\u003c\/strong\u003e Satin anodized\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePower Source:\u003c\/strong\u003e Heat expansion, no electricity or batteries required\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch6\u003eHOW IT WORKS\u003c\/h6\u003e\n\u003cp\u003eAutomatic greenhouse vent openers are one of the most effective ways to regulate temperature and protect your plants year-round. As temperatures rise, the opener gradually lifts the vent to release excess heat. When it cools down, the vent closes automatically, helping maintain a stable growing environment day and night.\u003c\/p\u003e\n\u003ch6\u003eWARRANTY\u003c\/h6\u003e\n\u003cp\u003eBacked by a 2-year guarantee for added confidence in performance and durability.\u003c\/p\u003e\n\u003ch6\u003eFREQUENTLY ASKED QUESTIONS\u003c\/h6\u003e\n\u003cp\u003e\u003cstrong\u003eHow does an automatic greenhouse vent opener work?\u003c\/strong\u003e\u003cbr\u003eIt uses a heat-sensitive piston that expands as temperatures rise, opening the vent. When temperatures drop, the piston contracts and closes the vent.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo I need electricity or batteries?\u003c\/strong\u003e\u003cbr\u003eNo. This unit operates entirely on thermal expansion, so it requires no power source.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fit my greenhouse?\u003c\/strong\u003e\u003cbr\u003eThe clip-on design fits many standard greenhouse roof vents, especially aluminum frames. Please confirm compatibility with your greenhouse model before ordering.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy should I use an auto vent opener?\u003c\/strong\u003e\u003cbr\u003eIt helps prevent overheating, improves airflow, and keeps your greenhouse environment more stable, even when you’re not there to manage it manually.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":47355183792277,"sku":"ALTBAXLAU","price":150.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Bayliss-XL-roof-vent-opener-1.png?v=1778815608"},{"product_id":"alton-bayliss-xl-roof-vent-opener-piston-replacement","title":"Alton | Bayliss XL Roof Vent Opener Piston Replacement","description":"\u003cp\u003eThe Bayliss XL Piston or Power Tube is a direct replacement component designed specifically for the Bayliss XL Automatic Greenhouse Vent Opener. If your current unit is no longer responding as it should, replacing the power tube is a simple and cost-effective way to restore smooth, temperature-driven vent operation.\u003c\/p\u003e\n\u003cp\u003eThis tube contains a heat-sensitive wax core that expands as temperatures rise and contracts as they fall, driving the piston that opens and closes your greenhouse vent automatically. It helps maintain a stable growing environment without electricity or manual adjustment.\u003c\/p\u003e\n\u003ch6\u003eKEY FEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDesigned for Bayliss XL only:\u003c\/strong\u003e Compatible exclusively with the Bayliss XL Autovent.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRestores vent performance:\u003c\/strong\u003e Brings your automatic opener back to proper working condition.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeat-activated operation:\u003c\/strong\u003e Uses wax expansion for reliable, power-free control.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCost-effective solution:\u003c\/strong\u003e Extend the life of your existing vent opener.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eSPECIFICATIONS\u003c\/h6\u003e\n\u003cdiv style=\"background-color: #f4f8f2; padding: 18px; border-radius: 12px; margin: 14px 0;\"\u003e\n\u003cp\u003e\u003cstrong\u003ePRODUCT TYPE:\u003c\/strong\u003e Replacement power tube\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCOMPATIBILITY:\u003c\/strong\u003e Bayliss XL Automatic Vent Opener only\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eLENGTH (EXCLUDING PISTON):\u003c\/strong\u003e 7.38 inches\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eLENGTH (METRIC):\u003c\/strong\u003e 18.75 cm\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch6\u003eINSTALLATION GUIDE\u003c\/h6\u003e\n\u003cp\u003eFor accurate setup and proper function, the power tube must be cooled before installation. Place the tube in a refrigerator for approximately 30 minutes to allow the wax inside to contract.\u003c\/p\u003e\n\u003cp\u003eAfter cooling, press the piston rod firmly against a hard surface until it retracts into the tube. Install the unit with the vent arms in the closed position to ensure proper alignment with the vent and mounting points.\u003c\/p\u003e\n\u003cp\u003eSkipping the cooling step may prevent the unit from being set correctly.\u003c\/p\u003e\n\u003ch6\u003eMAINTENANCE AND CARE\u003c\/h6\u003e\n\u003cp\u003eEnsure the piston remains clean and free of debris for smooth operation. Periodically check alignment and mounting points to maintain consistent vent performance over time.\u003c\/p\u003e\n\u003ch6\u003eFREQUENTLY ASKED QUESTIONS\u003c\/h6\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the power tube do?\u003c\/strong\u003e\u003cbr\u003eThe power tube contains a wax-filled cylinder that expands with heat, pushing the piston to open your greenhouse vent automatically.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy do I need to refrigerate the tube before installation?\u003c\/strong\u003e\u003cbr\u003eCooling the tube contracts the wax inside, allowing the piston to reset properly so the vent opener can be installed and calibrated accurately.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fit other auto vent brands?\u003c\/strong\u003e\u003cbr\u003eNo. This replacement tube is designed specifically for the Bayliss XL Autovent and will not fit standard or non-XL models.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhen should I replace the power tube?\u003c\/strong\u003e\u003cbr\u003eIf your vent no longer opens fully or responds slowly to temperature changes, replacing the power tube can restore proper operation.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":47355223900309,"sku":"ALTBATUBBCA","price":50.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Bayliss-XL-Autovent-piston.jpg?v=1778817433"},{"product_id":"alton-thermofor-roof-vent-opener-piston-replacement","title":"Alton | Thermofor Roof Vent Opener Piston Replacement","description":"\u003cp\u003eThe Thermofor Long Piston Replacement is a direct replacement cylinder designed for Thermofor automatic roof vent openers used in Alton greenhouses. If your current opener is no longer responding properly to temperature changes, replacing the piston is a simple way to restore reliable, automatic ventilation.\u003c\/p\u003e\n\n\u003cp\u003eThis heat-sensitive cylinder contains a wax core that expands as temperatures rise and contracts as they cool, driving the vent to open and close naturally. It helps maintain a stable growing environment without electricity or manual adjustment.\u003c\/p\u003e\n\n\u003ch6\u003eKEY FEATURES\u003c\/h6\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDesigned for Thermofor openers:\u003c\/strong\u003e Compatible with Thermofor roof vent systems used in Alton greenhouses.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRestores automatic ventilation:\u003c\/strong\u003e Brings your vent opener back to proper working condition.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeat-powered operation:\u003c\/strong\u003e No electricity or batteries required.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReplacement cylinder only:\u003c\/strong\u003e No fittings or hardware included.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch6\u003eSPECIFICATIONS\u003c\/h6\u003e\n\u003cdiv style=\"background-color: #f4f8f2; padding: 18px; border-radius: 12px; margin: 14px 0;\"\u003e\n  \u003cp\u003e\u003cstrong\u003ePRODUCT TYPE:\u003c\/strong\u003e Replacement piston cylinder\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eCOMPATIBILITY:\u003c\/strong\u003e Thermofor roof vent openers only\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eOVERALL LENGTH:\u003c\/strong\u003e 8 inches\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eMETRIC LENGTH:\u003c\/strong\u003e 200 mm\u003c\/p\u003e\n  \u003cp\u003e\u003cstrong\u003eINCLUDED:\u003c\/strong\u003e Cylinder only (no fittings)\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch6\u003eINSTALLATION GUIDE\u003c\/h6\u003e\n\u003cp\u003eFor proper installation and accurate operation, the piston must be cooled before fitting. Place the cylinder in a refrigerator for approximately 30 minutes. This allows the wax inside to contract so the piston rod can be fully depressed.\u003c\/p\u003e\n\n\u003cp\u003eOnce cooled, press the piston rod firmly against a hard surface until it retracts into the cylinder. Install the unit with the vent arms in the closed position to ensure correct alignment with the vent and mounting points.\u003c\/p\u003e\n\n\u003cp\u003eSkipping the cooling step may prevent the unit from being set correctly.\u003c\/p\u003e\n\n\u003ch6\u003eMAINTENANCE AND CARE\u003c\/h6\u003e\n\u003cp\u003eKeep the piston clean and free from debris to ensure smooth movement. Periodically check alignment and mounting points to maintain consistent vent performance.\u003c\/p\u003e\n\n\u003ch6\u003eFREQUENTLY ASKED QUESTIONS\u003c\/h6\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat does the piston do in a greenhouse vent opener?\u003c\/strong\u003e\u003cbr\u003e\nThe piston contains a wax-filled core that expands with heat, pushing the vent open. As temperatures drop, it contracts and closes the vent.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDo I need electricity for this to work?\u003c\/strong\u003e\u003cbr\u003e\nNo. The piston operates entirely through heat expansion, so no power source is required.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhy do I need to refrigerate the piston before installation?\u003c\/strong\u003e\u003cbr\u003e\nCooling contracts the wax inside, allowing the piston to reset properly so it can be installed and calibrated accurately.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWill this fit other vent opener brands?\u003c\/strong\u003e\u003cbr\u003e\nNo. This replacement piston is designed specifically for Thermofor roof vent openers and may not be compatible with other brands.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":47355256438933,"sku":"ALTTHCY0002L","price":45.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/Thermofor-Autovent-piston.jpg?v=1778818527"},{"product_id":"alton-thermofor-louvered-window-opener-piston-replacement","title":"Alton | Thermofor Louver Window Opener Piston Replacement","description":"\u003cp\u003eThe Thermofor Louver Vent Replacement Cylinder is designed to restore smooth, automatic operation to your greenhouse louver vent opener. Compatible with Thermofor, Robinsons, and Alton branded louver openers, this replacement cylinder helps maintain proper airflow and temperature control without manual adjustment.\u003c\/p\u003e\n\u003cp\u003eInside the cylinder is a heat-sensitive wax core that expands as temperatures rise and contracts as they cool. This natural movement powers the opening and closing of your louver vents, improving ventilation and protecting your plants from overheating.\u003c\/p\u003e\n\u003ch6\u003eKEY FEATURES\u003c\/h6\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide compatibility:\u003c\/strong\u003e Fits Thermofor, Robinsons, and Alton louver vent openers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRestores automatic ventilation:\u003c\/strong\u003e Keeps airflow consistent and responsive to temperature changes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeat-powered operation:\u003c\/strong\u003e No electricity or batteries required.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacement cylinder only:\u003c\/strong\u003e No fittings or mounting hardware included.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch6\u003eSPECIFICATIONS\u003c\/h6\u003e\n\u003cdiv style=\"background-color: #f4f8f2; padding: 18px; border-radius: 12px; margin: 14px 0;\"\u003e\n\u003cp\u003e\u003cstrong\u003ePRODUCT TYPE:\u003c\/strong\u003e Replacement cylinder\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCOMPATIBILITY:\u003c\/strong\u003e Thermofor, Robinsons, and Alton louver vent openers\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eOVERALL LENGTH:\u003c\/strong\u003e 7 inches\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMETRIC LENGTH:\u003c\/strong\u003e 170 mm\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eINCLUDED:\u003c\/strong\u003e Cylinder only (no fittings)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch6\u003eHOW IT WORKS\u003c\/h6\u003e\n\u003cp\u003eThe cylinder uses a wax-filled core that reacts to temperature changes. As the greenhouse warms up, the wax expands and pushes the piston to open the louver vent. When temperatures drop, the wax contracts, allowing the vent to close. This automatic process helps maintain a stable growing environment throughout the day.\u003c\/p\u003e\n\u003ch6\u003eMAINTENANCE AND CARE\u003c\/h6\u003e\n\u003cp\u003eKeep the cylinder clean and free from debris to ensure smooth operation. Periodically inspect your louver opener to maintain proper alignment and performance.\u003c\/p\u003e\n\u003ch6\u003eFREQUENTLY ASKED QUESTIONS\u003c\/h6\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does a louver vent opener cylinder do?\u003c\/strong\u003e\u003cbr\u003eIt controls the opening and closing of your louver vents using heat expansion, helping regulate airflow and temperature inside your greenhouse.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo I need electricity or batteries?\u003c\/strong\u003e\u003cbr\u003eNo. The cylinder operates entirely on heat expansion, so it requires no power source.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fit my greenhouse vent opener?\u003c\/strong\u003e\u003cbr\u003eThis cylinder is compatible with Thermofor, Robinsons, and Alton louver vent openers. Always confirm your model before purchasing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhen should I replace the cylinder?\u003c\/strong\u003e\u003cbr\u003eIf your louver vent no longer opens or responds slowly to temperature changes, replacing the cylinder can restore proper function.\u003c\/p\u003e","brand":"Alton","offers":[{"title":"Default Title","offer_id":47355269349525,"sku":"ALTTHCY0002L","price":45.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0097\/9959\/8140\/files\/thermofor-piston-for-louver-opener.jpg?v=1778819579"}],"url":"https:\/\/mygreenhousestore.com\/collections\/discover-premium-greenhouse-roof-vents-louver-windows-automatic-openers.oembed","provider":"MyGreenhouseStore.com","version":"1.0","type":"link"}