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 $89.99The AC Infinity CLOUDLINE S4 and the AC Infinity CLOUDLINE T4 are evenly matched, rated 3.6 and 3.5. The AC Infinity CLOUDLINE S4 leads on value. The AC Infinity CLOUDLINE T4 wins on controls. The AC Infinity CLOUDLINE S4 costs $29.01 less ($89.99 vs $119).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
The S4 fan paired with a temperature and humidity controller and WiFi app. For a small grow tent that should run itself.
Amazon $119Which should you buy?
- Choose the AC Infinity CLOUDLINE S4 for value ($39.82 per 100 CFM ($89.99, 226 CFM) vs $52.65 per 100 CFM ($119, 226 CFM)).
- Choose the AC Infinity CLOUDLINE T4 for controls (speed controller included, temperature and humidity control, phone app, timer or cycle modes vs speed controller included).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 4 in inline duct fan; a clear win is highlighted. How we rank explains each one.
| Factor weight | AC Infinity CLOUDLINE S4 | AC Infinity CLOUDLINE T4 |
|---|---|---|
| Overall rating | 3.6/5 | 3.5/5 |
| Value 25% | 47 $39.82 per 100 CFM ($89.99, 226 CFM) | 15 $52.65 per 100 CFM ($119, 226 CFM) |
| Efficiency 25% | 56 8.1 CFM per watt (226 CFM, 28 W) | 56 8.1 CFM per watt (226 CFM, 28 W) |
| Airflow 15% | 88 226 CFM through 4 in duct | 88 226 CFM through 4 in duct |
| Noise 15% | 97 26 dBA at full speed | 97 26 dBA at full speed |
| Controls 10% | 40 speed controller included | 100 speed controller included, temperature and humidity control, phone app, timer or cycle modes |
| Warranty 10% | 25 2-year warranty | 25 2-year warranty |
Specifications
| AC Infinity CLOUDLINE S4 | AC Infinity CLOUDLINE T4 | |
|---|---|---|
| Performance | ||
| Duct size | 4 in | 4 in |
| Rated airflow | 226 CFM | 226 CFM |
| Static pressure (not scored) | 223 Pa | 223 Pa |
| Power at full speed | 28 W | 28 W |
| Power figure | Max power draw | Max power draw |
| Average power (not scored) | 21 W | 21 W |
| Airflow per watt | 8.1 CFM/W | 8.1 CFM/W |
| Price per 100 CFM | $39.82 | $52.65 |
| Noise at full speed | 26 dBA | 26 dBA |
| Top speed | 2,800 RPM | 2,800 RPM |
| Controls | ||
| Motor | EC | EC |
| Controller | 10-speed controller | Environment controller |
| Speeds | 10 | 10 |
| Temperature and humidity control | No | Yes |
| Phone app | No | Yes |
| Timer or cycle modes | No | Yes |
| Build | ||
| Housing | Plastic | Plastic |
| Ingress rating | IP44 | - |
| Voltage | 100-240 V | 100-240 V |
| Warranty | 2 years | 2 years |
