---
title: "4 Inch Carbon Filter — $55K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/patio-lawn-garden/4-inch-carbon-filter"
last_updated: "2026-08-09T09:08:28.683Z"
locale: en
meta:
description: "Niche score 40/100 · $55K/yr market · 22K searches/yr · $39.03 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 40/100 · $55K/yr market · 22K searches/yr · $39.03 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "4 Inch Carbon Filter — $55K/yr Amazon US Niche (2026) - Flapen"
---
# **4 inch carbon filter**
**Skip it**
A small market ($55K/yr) — this niche doesn't clear our bar today.
Market size 14Growth 19Conversion 71Competition 22Returns 65Price range 95Avg price 95Brand share 25Review moat 45Quality gap 38
**Avg price**
**Incredible****$39.03**
avg listing price — sweet spot $15–$100
**Price range**
**Incredible****$16.06–$89.42**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Conversion**
**Good****6.5%**
search→purchase rate — share of searches ending in a sale
**Returns**
**Good****2.4%**
return rate — above 5% kills the launch gate
**Review moat**
**Okay****2,023.07**
avg incumbent reviews — the moat a new listing must climb
**Quality gap**
**Okay****4.5★**
avg incumbent rating — lower means beatable quality
**Brand share**
**Okay****90%**
top-5 brand share — brands hold most of the demand
**Competition**
**Bad****73%**
top-5 click share — a locked-up shelf
**Growth**
**Bad****-12.1%**
90-day search growth — must beat 0% to launch
**Market size**
**Bad****$55K**
$55K/yr · 22K searches
According to Flapen's Amazon United States niche tracking, 4 inch carbon filter is a $55K/yr Amazon United States market (22K searches/yr). The top 5 brands hold 90% of demand. Verdict: Skip it — 40/100.
Data updated Jul 9, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **4 inch carbon filter market data**
- **Units sold / yr**
- **2K–2K**
- avg 0–100/product
- **Revenue / yr**
- **$59K–$78K**
- units × avg price
- **Conversion rate**
- **6.5%**
- **Avg BSR**
- **#95**
- **Page quality**
- **0%**
- **Prime**
- **100%**
- **Sponsored**
- **79%**
- **Out of stock**
- **11.1%**
- **Avg brand age**
- **50 months**
- **Avg seller age**
- **228 days**
## **Competition & brand share**
The top 5 products capture 73% of clicks — a locked-up shelf that new listings rarely crack.
**Brands**
**9 **▼falling
**Sellers**
**11**
**Top-5 brand share**
**90%**
Top 20: 100%
**Top-5 click share**
**73%**
Top 20: 100%
**Open market**
**6%**
- VIVOSUN33% - vanleno18% - MELONFARM14% - ATOUR13% - AC Infinity12% - HYDROWE4% - Open — no brand owns it (3 brands, 6%)
## **Demand & seasonality**
Weekly Amazon search volume, last 104 weeks — -12.1% search growth over the last 90 days.
900700Holiday '24Spike '25Black Friday '25 seasonSepDecMarJunAugNovMarMay
No pronounced peak months · busiest ÷ quietest = 1.5×
[**Open Trend **](https://flapen.com/research/us/patio-lawn-garden/4-inch-carbon-filter/trend)
## **Top 4 inch carbon filter search terms**
- **4 inch carbon filter**13K/yr-14.3%5.0% conv. - **4 carbon filter**6K/yr+0.4%8.1% conv. - **4in carbon filter**3K/yr-23.4%5.6% conv. [**All search terms **](https://flapen.com/research/us/patio-lawn-garden/4-inch-carbon-filter/search-terms)
## **Top 4 inch carbon filter products on Amazon**
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
0%10%$6K20%$11K30%$17K40%$22K1101001K10K100K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 14 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**VIVOSUN 4 Inch Air Carbon Filter Smellines Control with Australia Virgin Charcoal for Inline Duct Fan Grow Tent Pre-filter Included Reversible Flange 4 x 12**VIVOSUN**$38.04**4.6★10,044 rev](https://www.amazon.com/dp/B01DXYMBU6) [2**vanleno 4inch Carbon Filter Odor Control with Australia Virgin Charcoal Two Prefilter 1 Pair Rope Hanger Included for Inline Duct Fan Grow Tent Hydroponics Odor Scrubber**vanleno**$30.35**4.6★2,935 rev](https://www.amazon.com/dp/B085DMC2LX) [3**MELONFARM 4 Inch Air Carbon Filter Smelliness Control with Australia Virgin Charcoal Odor Removal Carbon Filter for Grow Tent Inline Fan Hydroponics Pre-Filter Included Insulated Flange 4 x 11**MELONFARM**$28.79**4.4★750 rev](https://www.amazon.com/dp/B0C84QNZ4L) [4**ATOUR 4 Air Carbon Filter with Australian Virgin Charcoal Superior Odor Control for Grow Tent Smelliniss Scrubber Inline Fans Hydroponics. Includes Pre-Filter & Insulated Flange 4x11**ATOUR**$28.14**4.6★18 rev](https://www.amazon.com/dp/B0FC27ZD36) [5**AC Infinity Air Carbon Filter 4 with Premium Australian Virgin Charcoal for Inline Duct Fan Odor Control Hydroponics Grow Rooms**AC Infinity**$49.65**4.8★10,224 rev](https://www.amazon.com/dp/B07GSKFBL8)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Carbon Filter 4 with Premium Australian Virgin Charcoal Grow Rooms Reusable Charcoal Filter for Grow Tent Grow Room Hydroponics for Inline Duct Fan (Diameter 4 inches - Length 10 inches)**GROW BUDDY**$29.91**1 rev4mo ago](https://www.amazon.com/dp/B0GS16V9PZ) [**ATOUR 4 Air Carbon Filter with Australian Virgin Charcoal Superior Odor Control for Grow Tent Smelliniss Scrubber Inline Fans Hydroponics. Includes Pre-Filter & Insulated Flange 4x11**ATOUR**$28.14**18 rev1y ago](https://www.amazon.com/dp/B0FC27ZD36) [**ATOUR 4 Inch Air Carbon Filter with Australian Virgin Charcoal Odor Control. Built-in 5.5 Quiet Fan with Speed Control for Inline Duct Fans & Grow Tents. Includes Vent Cover + Pre-Filter 4x13.4**ATOUR**$41.45**63 rev1y ago](https://www.amazon.com/dp/B0FC26Q61Y) [**MELONFARM 4 Inch Air Carbon Filter Smelliness Control with Australia Virgin Charcoal Odor Removal for Grow Tent Inline Fan 8 Ducting Cooling & Vent Cover Included Insulated Flange 4 x 11**MELONFARM**$37.09**8 rev1y ago](https://www.amazon.com/dp/B0FBWH57P8) [**AC Infinity Refillable Carbon Filter Kit 4 with Additional Refill Odor Removal Air Scrubber For 4 Inline Fan and Ducting Reusable Charcoal Filter for Grow Tent Grow Room Hydroponics**AC Infinity**$89.42**495 rev2y ago](https://www.amazon.com/dp/B0CFBM7JKT)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Carbon Filter 4 with Premium Australian Virgin Charcoal Grow Rooms Reusable Charcoal Filter for Grow Tent Grow Room Hydroponics for Inline Duct Fan (Diameter 4 inches - Length 10 inches)**GROW BUDDY**$29.91**5.0★**▲ 355%**](https://www.amazon.com/dp/B0GS16V9PZ) [**MELONFARM 4 Inch Air Carbon Filter Smelliness Control with Australia Virgin Charcoal Odor Removal for Grow Tent Inline Fan 8 Ducting Cooling & Vent Cover Included Insulated Flange 4 x 11**MELONFARM**$37.09**4.1★**▲ 290%**](https://www.amazon.com/dp/B0FBWH57P8) [**ATOUR 4 Air Carbon Filter with Australian Virgin Charcoal Superior Odor Control for Grow Tent Smelliniss Scrubber Inline Fans Hydroponics. Includes Pre-Filter & Insulated Flange 4x11**ATOUR**$28.14**4.6★**▲ 69%**](https://www.amazon.com/dp/B0FC27ZD36) [**vanleno 4inch Carbon Filter Odor Control with Australia Virgin Charcoal Two Prefilter 1 Pair Rope Hanger Included for Inline Duct Fan Grow Tent Hydroponics Odor Scrubber**vanleno**$30.35**4.6★**▲ 49%**](https://www.amazon.com/dp/B085DMC2LX) [**Spider Farmer 4 Inch Air Carbon Filrer Smelliness Control with Premium Australia Virgin Charcoal for Inline Duct Fan Grow Tent Odor Control Hydroponics Pre-Filter Included Reversible Flange**Spider Farmer**$44.78**4.4★**▲ 48%**](https://www.amazon.com/dp/B09MTDFBPS)
**~~View all trending →~~**
## **What buyers say about 4 inch carbon filter**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Smell**27%
*“No odor”*
**Quality-Overall**14%
*“The quality is really good”*
**Value For Money**11%
*“Amazing value for the quality you get”*
**Advertised Vs Actual Product**11%
*“Works as described”*
**Filtration**10%
*“Good filter”*
**Size-Overall**5%
*“It's a good size”*
**Ease Of Use**4%
*“Many uses”*
**Strength**3%
*“Seems sturdy for a good price and easily installed”*
**Assembly/Installation**3%
*“easily installed”*
**Refills-Overall**2%
*“Useful refill kit”*
### **What buyers complain about **
**Smell**18%
*“so those chemical smells don't stand a chance of taking over the room”*
**Filtration**14%
*“Not a big fan of the pre filters”*
**Refills-Overall**12%
*“Doesnt work once refilled”*
**Quality-Overall**11%
*“Garbage”*
**Durability**8%
*“Doesnt last long at all”*
**Scratch Resistance**6%
*“Dented up”*
**Functionality-Overall**6%
*“The last one I bought is not working at all”*
**Size-Overall**3%
*“Too small”*
**Charging**3%
*“all the big names are copying their idead and charging double”*
**Ease Of Cleaning**2%
*“messy”*
### **Top return reasons **
**Size-Overall**49%
**Filtration**13%
**Functionality-Overall**9%
**Advertised Vs Actual Product**8%
**Compatibility-Overall**3%
**Smell**3%
**Value For Money**2%
**Leak-Proof**2%
**Product Condition**2%
**Defective Material/Parts**1%
## **Common questions**
- **Is 4 inch carbon filter profitable to sell on Amazon United States?**
- The niche generates $55K/yr across 14 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -12.1%. Flapen's verdict: Skip it (40/100).
- **How competitive is the 4 inch carbon filter niche?**
- 9 brands and 11 sellers compete. The top 5 products take 73% of clicks and top 5 brands hold 90% of demand.
- **What do buyers complain about in 4 inch carbon filter?**
- Top complaints mined from reviews: Smell, Filtration, Refills-Overall. The return rate is 2.4%.
- **When does demand for 4 inch carbon filter peak?**
- Demand is steady year-round — the busiest month runs 1.5× the quietest.
- **What does it cost to enter the 4 inch carbon filter niche?**
- Listings span $16.06–$89.42; the average listing price is $39.03 (sweet spot $15–$100). The average incumbent carries 2,023 reviews — the moat a new listing must climb.
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