4 inch carbon filter
Skip itA small market ($55K/yr) — this niche doesn't clear our bar today.
Avg price
Incredible$39.03avg listing price — sweet spot $15–$100
Price range
Incredible$16.06–$89.42cheapest to priciest tracked listing — scored on the share inside $15–$100
Conversion
Good6.5%search→purchase rate — share of searches ending in a sale
Returns
Good2.4%return rate — above 5% kills the launch gate
Review moat
Okay2,023.07avg incumbent reviews — the moat a new listing must climb
Quality gap
Okay4.5★avg incumbent rating — lower means beatable quality
Brand share
Okay90%top-5 brand share — brands hold most of the demand
Competition
Bad73%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
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.No pronounced peak months · busiest ÷ quietest = 1.5×
Top 4 inch carbon filter search terms
- 4 inch carbon filter13K/yr
- 4 carbon filter6K/yr
- 4in carbon filter3K/yr
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.
All 14 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
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$38.044.6★10,044 rev
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$30.354.6★2,935 rev
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$28.794.4★750 rev
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$28.144.6★18 rev
AC Infinity Air Carbon Filter 4 with Premium Australian Virgin Charcoal for Inline Duct Fan Odor Control Hydroponics Grow Rooms
AC Infinity$49.654.8★10,224 rev
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$29.911 rev
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$28.1418 rev
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$41.4563 rev
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$37.098 rev
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$89.42495 rev
Trending
90-day click momentumCarbon 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$29.915.0★
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$37.094.1★
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$28.144.6★
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$30.354.6★
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$44.784.4★
What buyers say about 4 inch carbon filter
What buyers praise and complain about, mined from review topics.What buyers love
“No odor”
“The quality is really good”
“Amazing value for the quality you get”
“Works as described”
“Good filter”
“It's a good size”
“Many uses”
“Seems sturdy for a good price and easily installed”
“easily installed”
“Useful refill kit”
What buyers complain about
“so those chemical smells don't stand a chance of taking over the room”
“Not a big fan of the pre filters”
“Doesnt work once refilled”
“Garbage”
“Doesnt last long at all”
“Dented up”
“The last one I bought is not working at all”
“Too small”
“all the big names are copying their idead and charging double”
“messy”
Top return reasons
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.