{"product_id":"ac-infinity-raxial-s4-inline-booster-duct-fan-4-variable-speed-low","title":"AC Infinity RAXIAL S4 Inline Booster Duct Fan 4 - Variable Speed, Low","description":"\u003cp\u003eIn this review the AC Infinity RAXIAL S4 is presented as a compact inline booster fan intended for anyone needing a straightforward way to increase airflow in HVAC ducts or ventilate small home spaces. The bottom line: it is best for homeowners and hobbyists who want a durable, low-noise booster with a simple three-speed controller, because its unibody die-cast construction and dual ball bearings deliver steady operation while keeping vibration and maintenance to a minimum.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eInline booster design:\u003c\/strong\u003e boosts existing airflow in ducts to improve ventilation in attics, basements, bathrooms, workshops and similar spaces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVariable speed controller:\u003c\/strong\u003e three-speed control lets you balance airflow and noise to suit different rooms and times of day.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnibody die-cast construction:\u003c\/strong\u003e a seamless housing reduces vibration and improves durability for long-term, stable performance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAC shaded-pole motor:\u003c\/strong\u003e uses balanced steel blades and permanently lubricated dual ball bearings for quieter continuous use and less maintenance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact size and airflow:\u003c\/strong\u003e the 4 in duct fits tight spaces while delivering up to 106 CFM for targeted boost applications.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe RAXIAL S4 is a good fit for homeowners, workshop users, or DIY HVAC improvers who need a compact inline fan to increase ventilation without a big installation footprint. Its modest airflow and low 28 dBA noise level make it useful for intermittent boost in bathrooms, kitchens, or localized duct sections.\u003c\/p\u003e\n\u003cp\u003eIt is not aimed at large commercial HVAC projects or whole-house circulation where higher CFM or larger duct work is required; buyers who need very high static pressure performance or larger duct diameters should consider a larger industrial blower.\u003c\/p\u003e\n\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSolid build thanks to the unibody die-cast housing that limits vibration and rattles.\u003c\/li\u003e\n\u003cli\u003eUseful three-speed controller for adjusting airflow and keeping noise down when needed.\u003c\/li\u003e\n\u003cli\u003eQuiet operation at typical settings, with a rated noise around 28 dBA for less intrusive running.\u003c\/li\u003e\n\u003cli\u003eLow maintenance motor with permanently lubricated dual ball bearings for continuous duty.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAirflow is modest at 106 CFM, so some users report mixed results when expecting larger volume movement.\u003c\/li\u003e\n\u003cli\u003eNot suitable for large-scale HVAC needs or for ducts that require greater diameter or pressure capacity.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eDuct size\u003c\/td\u003e\n\u003ctd\u003e4 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e7.28 x 3.95 x 3.95 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAirflow\u003c\/td\u003e\n\u003ctd\u003e106 CFM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNoise level\u003c\/td\u003e\n\u003ctd\u003e28 dBA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMotor type\u003c\/td\u003e\n\u003ctd\u003eAC shaded-pole induction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBearings\u003c\/td\u003e\n\u003ctd\u003eDual ball\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe RAXIAL S4 is a compact, well-built inline booster that represents good value for homeowners and small-scale users who need targeted airflow increases and low-noise operation. Its unibody housing and permanently lubricated bearings make it reliable for long runs, while the speed controller gives practical flexibility for everyday ventilation tasks.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fan fit a 4 in flexible duct?\u003c\/strong\u003e\u003cbr\u003eYes, the unit is specified for a 4 in duct and fits typical 4 in flexible and rigid ductwork used in homes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow loud is the fan in normal use?\u003c\/strong\u003e\u003cbr\u003eThe manufacturer rating is about 28 dBA; most users find it quiet at lower speeds though noise perception varies by installation and mounting.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs the motor maintenance free?\u003c\/strong\u003e\u003cbr\u003eThe AC shaded-pole motor uses permanently lubricated dual ball bearings, so routine lubrication is not required for normal operation.\u003c\/p\u003e","brand":"AC Infinity","offers":[{"title":"Default Title","offer_id":48236961464539,"sku":"B07ZL6FDYG","price":34.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/41nwgUmlcKL._AC_SL1000.jpg?v=1770824566","url":"https:\/\/gearmusthave.com\/products\/ac-infinity-raxial-s4-inline-booster-duct-fan-4-variable-speed-low","provider":"GearMustHave","version":"1.0","type":"link"}