A 4 in fan suits a 2x2 or 3x3 grow tent, a closet, an AV cabinet or a single bathroom. These move 140 to 230 CFM in free air and most draw under 35 W, so running one around the clock costs little. With a 4 in carbon filter attached, pick one near the top of that airflow range so you are not running it flat out.
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Full ranking 7
- VIVOSUN AeroZesh T4#1 of 7Full review
A very efficient 4 in EC fan with a 10-speed controller and on/off cycle modes, at a lower price than the CLOUDLINE S4.
Amazon $71.99$71.994 in210 CFM10.5 CFM/W28 dBA - AC Infinity CLOUDLINE S4#2 of 7Full review
A quiet, efficient 4 in fan for small grow tents, closets and AV cabinets. The S line adds a longer cord and more airflow than the cheaper A4.
Amazon $89.99$89.994 in226 CFM8.1 CFM/W26 dBA - AC Infinity CLOUDLINE T4#3 of 7Full review
The S4 fan paired with a temperature and humidity controller and WiFi app. For a small grow tent that should run itself.
Amazon $119$1194 in226 CFM8.1 CFM/W26 dBA - Spider Farmer 4 in Inline Fan#4 of 7Full review
A quiet, efficient 4 in EC fan for small grow tents, priced below the CLOUDLINE S4.
Amazon $79.99$79.994 in205 CFM7.6 CFM/W26.8 dBA - Hon&Guan PRO 4 in Inline Fan#5 of 7Full review
A low-cost 4 in EC fan with strong rated airflow. Its power draw is not published, which keeps it below documented rivals.
Amazon $63.99$63.994 in212 CFM-28 dBA - AC Infinity CLOUDLINE A4#6 of 7Full review
The budget member of the CLOUDLINE 4 in range, with the same controller and build but less airflow than the S4. Worth it for its higher static pressure behind a small carbon filter.
Amazon $79.99$79.994 in165 CFM4.7 CFM/W29 dBA - TerraBloom ECMF-100 4 in EC Fan#7 of 7Full review
A very quiet 4 in fan for a bedroom closet or a small tent where noise matters more than airflow.
Amazon $89.99$89.994 in141 CFM6.7 CFM/W18 dBA
