AC Infinity S4 vs Vivosun Inline Fan Test

Q: Which 4-inch inline fan won the old comparison?

The AC Infinity was HWGrow’s pick because it looked stronger in the visual test and drew 28 watts versus 59 watts.

Short answer: the historical AC Infinity 4-inch fan moved the card sleeve farther and used 28 watts in my comparison, while the Vivosun used 59 watts. That made the AC Infinity my preferred long-term choice. But this was not a calibrated airflow or sound test, and current product generations must be compared from scratch.

Old-model warning: the video documents two fans and prices from 2021. AC Infinity and Vivosun now sell multiple 4-inch fan/controller combinations. Match the exact current model number, controller, power draw, certification and warranty—do not buy by brand name alone.

My original AC Infinity versus Vivosun 4-inch inline-fan comparison. English captions are available from the CC menu.

Video chapters

0:00 — What the comparison covers
0:22 — Historical purchase prices
0:42 — Old advertised CFM figures
0:59 — Side-by-side airflow visual
1:20 — Informal sound comparison
1:38 — Measured wattage and energy formula
2:17 — Historical 90-day operating cost
2:38 — Original verdict

Timestamp links open the standard HWGrow pop-out player at the selected moment without losing your reading position.

What the test supports—and what it does not

Observed wall draw: 28 watts for the AC Infinity and 59 watts for the Vivosun at the tested settings.
Visual airflow: the AC Infinity pushed the lightweight sleeve farther at full speed.
Advertised airflow: the old figures shown were 205 CFM and 190 CFM.
Noise: the camera recording was an informal impression, not a controlled decibel measurement.
Real system performance: neither fan was measured through the same filter-and-duct resistance on a calibrated airflow bench.

A sleeve bending farther is easy to see, but it does not prove exact CFM. Duct length, bends, filter restriction and static pressure determine how much air reaches the real tent. The honest conclusion is that the AC Infinity looked stronger in this simple test and drew substantially less power—not that the visual validated every manufacturer number.

AC Infinity and Vivosun 4-inch inline fans compared side by side — The exact historical 4-inch fans used in HWGrow’s comparison.

Recalculate the operating cost with your rate

The old video used 24 hours a day for 90 days. The energy math still works:

kilowatt-hours = watts ÷ 1,000 × hours per day × days

At those measured draws, continuous 90-day use equals 60.48 kWh for 28 watts and 127.44 kWh for 59 watts. Multiply each result by the current rate on your electric bill. Do not reuse the video’s old New York price assumption.

My historical verdict: the AC Infinity cost more up front but won my simple performance-and-power comparison. For a current purchase, compare the complete fan/controller/filter system and expected duty cycle—not just the fan price.

How the current listings differ

AC Infinity’s current CLOUDLINE S4 page lists 226 CFM, 28 watts maximum, a 10-speed controller and current safety certifications. Vivosun’s current R4 page lists 190 CFM and 59 watts. These are manufacturer specifications, not proof that every current bundle or seller listing matches the exact fans filmed in 2021.

AC Infinity savings: If you buy from AC Infinity directly, use code EVYGROWS at checkout for additional savings on eligible products.

Before buying, size the fan for the tent, carbon filter and duct path; then check the equipment-generation guide for the difference between an old review and a current product.

Useful ventilation tools

AC Infinity 4-inch fanVerify the exact controller, power draw and current certification.Check Current Options

Vivosun 4-inch fanCompare current bundles, controls, filter compatibility and warranty.Check Current Options

Plug-in electricity meter for measuring inline fan power draw

Plug-in power meterMeasure actual wall draw instead of relying on a listing.Check Current Price

Affiliate disclosure: HWGrow may earn a commission from qualifying Amazon purchases at no additional cost to you. Equivalent current products can replace these links without changing the comparison method.

Next, follow the grow-tent fan and filter installation guide. If your duct route or room exhaust is unusual, Ask HWGrow with the tent size, filter size, duct length and number of bends.

Frequently asked questions

Which 4-inch inline fan won the old comparison?

The AC Infinity was my pick because it looked stronger in the visual test and drew 28 watts versus 59 watts.

Did the video prove exact airflow?

No. The sleeve test showed a visible difference, but exact airflow requires a calibrated test under the same duct and filter resistance.

Which fan was quieter?

The recording was not a controlled decibel test, so it should not be used as a precise noise ranking.

How do I compare energy cost today?

Multiply watts divided by 1,000 by daily runtime and days, then multiply the resulting kilowatt-hours by the current rate on your bill.