16 3/8 x 21 1/2 x1 air filter
Worth a lookShows searches that convert (15.2% search→purchase), but brand-locked demand (top 5 brands take 94% of clicks) keeps it on the watch list.
Conversion
Incredible15.2%search→purchase rate — share of searches ending in a sale
Price range
Incredible$32.71–$63.36cheapest to priciest tracked listing — scored on the share inside $15–$100
Avg price
Great$47.80avg listing price — sweet spot $15–$100
Returns
Great1.6%return rate — above 5% kills the launch gate
Growth
Good+39.8%90-day search growth — must beat 0% to launch
Market size
Good$302K$302K/yr · 42K searches
Review moat
Okay2,015.47avg incumbent reviews — the moat a new listing must climb
Competition
Bad70%top-5 click share — a locked-up shelf
Quality gap
Bad4.7★avg incumbent rating — lower means beatable quality
Brand share
Bad94%top-5 brand share — brand-locked demand
According to Flapen's Amazon United States niche tracking, 16 3/8 x 21 1/2 x1 air filter is a $302K/yr Amazon United States market (42K searches/yr). The top 5 brands hold 94% of demand. Demand peaks in Jun–Jul–Aug. Verdict: Worth a look — 54/100.
Data updated Jul 27, 2026 · scored weekly · How we score niches
16 3/8 x 21 1/2 x1 air filter market data
- Units sold / yr
- 6K–8K
- avg 250–500/product
- Revenue / yr
- $287K–$382K
- units × avg price
- Conversion rate
- 15.2%
- Avg BSR
- #229
- Page quality
- 0%
- Prime
- 73%
- Sponsored
- 80%
- Out of stock
- 9.6%
- Avg brand age
- 62 months
- Avg seller age
- 194 days
Competition & brand share
The top 5 products capture 70% of clicks — a locked-up shelf that new listings rarely crack.Brands
8 rising
Sellers
13
Top-5 brand share
94%
Top 20: 100%
Top-5 click share
70%
Top 20: 100%
Open market
4%
- Aerostar63%
- Chenzhit12%
- Glasfloss12%
- Qingzhug4%
- Fxnitang2%
- Filtrete2%
- Open — no brand owns it (2 brands, 4%)
Demand & seasonality
Weekly Amazon search volume, last 101 weeks — +39.8% search growth over the last 90 days.Peak months: Jun, Jul, Aug · busiest ÷ quietest = 2.5×
Top 16 3/8 x 21 1/2 x1 air filter search terms
- 16 3/8 x 21 1/2 x 1 air filter28K/yr
- air filter 16 3/8 x 21 1/2 x 15K/yr
- ac filter 16 3/8 x 21 1/2 x14K/yr
- aerostar 16 3/8 x 21 1/2 x 13K/yr
- 16 3/8 x 21 1/2 x1 air filter1K/yr
- air filter 16 3/8 x 21 1/2 x1637/yr
- 16 3/8 x21 1/2 x1 air filters22/yr
Top 16 3/8 x 21 1/2 x1 air 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 15 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Aerostar 16.375x21.5x1 MERV 11 Air Filter 4 Count ACTUAL SIZE (16.50 x 21.50 x 0.75) HVAC Air Conditioning & Furnace Filter for Dust Pet Dander Smoke & Allergies (MPR 1200 / FPR 7) Made in USA
Aerostar$33.334.7★4,106 rev
Aerostar 16.375x21.5x1 MERV 8 Air Filter 6 Count ACTUAL SIZE (16.50 x 21.50 x 0.75) HVAC Air Conditioning & Furnace Filter Captures Dust Lint & Pollen (MPR 600 / FPR 5) Made in USA
Aerostar$45.884.6★3,658 rev
Chenzhit (6 Pack) 16 3/8x21 1/2x1 Furnace Air Filters MPR 1900 & FPR 10 MERV 13 Pleated Air Filter (Actual Size: 16 3/8x21 1/2x3/4)
Chenzhit$58.614.7★647 rev
Glasfloss 16-3/8x21-1/2x1 MERV 10 Air Filters 6-Pack Fits Carrier
Glasfloss$60.304.8★2,728 rev
Aerostar 16.375x21.5x1 MERV 11 - 6 Count - Pleated HVAC Furnace & Air Conditioner Filters - Removes Dust Cold & Flu Germs Lint Mold Pet Dander Allergy-Causing Pollen Smog & Smoke
Aerostar$48.214.7★4,106 rev
Newest
by launch date
(6 Pack) 16 3/8x21 1/2x1 Air Filter MERV 13 MPR 1900 & FPR 10 Pleated Air Filter (Actual Size: 16 3/8x21 1/2x0.75)
Fxnitang$56.2154 rev
Chenzhit (6 Pack) 16 3/8x21 1/2x1 Furnace Air Filters MPR 1900 & FPR 10 MERV 13 Pleated Air Filter (Actual Size: 16 3/8x21 1/2x3/4)
Chenzhit$58.61647 rev
Filtrete 16.5x21.5x1 AC Furnace Air Filter MERV 8 MPR 700 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 4-Pack (Actual Size 16.19 x 21.19 x 0.81 in)
Filtrete$38.626,265 rev
Qingzhug 16 3/8x21 1/2x1 MERV 13 (6-Pack) Pleated Air Filter (Actual Size: 16 3/8x21 1/2x3/4) MPR 1900 & FPR 10 Furnace Air Filters
Qingzhug$56.26486 rev
Aerostar 16.375 x 21.5 x 1 MERV 6 Air Filter 6 Count ACTUAL SIZE (16.375 x 21.50 x 0.75) HVAC Furnace Filter for Dust Lint & Pollen Control (MPR 300 / FPR 3) Fits Carrier systems Made in USA
Aerostar$32.71242 rev
Trending
90-day click momentum(6 Pack) 16 3/8x21 1/2x1 Air Filter MERV 13 MPR 1900 & FPR 10 Pleated Air Filter (Actual Size: 16 3/8x21 1/2x0.75)
Fxnitang$56.214.7★
Aerostar 16.375x21.5x1 MERV 8 Air Filter 6 Count ACTUAL SIZE (16.50 x 21.50 x 0.75) HVAC Air Conditioning & Furnace Filter Captures Dust Lint & Pollen (MPR 600 / FPR 5) Made in USA
Aerostar$45.884.6★
Glasfloss 16-3/8x21-1/2x1 MERV 10 Air Filters 6-Pack Fits Carrier
Glasfloss$60.304.8★
16 3/8 x 21 1/2 x 1 Air Filter Frame with High Air Flow Washable Reusable Media Compatible Replacement for Fan Coil Filter KFAFK0212MED 317659-402 -MERV 5 Made in USA AC HVAC Furnace Filter Holder
CoreCarbon$63.364.9★
Aerostar 16.375x21.5x1 MERV 11 - 6 Count - Pleated HVAC Furnace & Air Conditioner Filters - Removes Dust Cold & Flu Germs Lint Mold Pet Dander Allergy-Causing Pollen Smog & Smoke
Aerostar$48.214.7★
What buyers say about 16 3/8 x 21 1/2 x1 air filter
What buyers praise and complain about, mined from review topics.What buyers love
“Good quality”
“Good Quality Filter With Reliable Fit”
“The dimensions were accurate”
“Perfect and Great price”
“As advertised”
“Easy to use”
“Just what I needed for my A/C unit”
“Reliable and Well Made”
“do a good job catching small and large particles”
“SO MUCH EASIER JUST WASH AND CLEAN AND REUSE”
What buyers complain about
“Was given the wrong size”
“These filters dont last very long because they collapse into the AC plenum within a month of use”
“This filter is incredibly cheap and flimsy”
“very cheap”
“item is not working for me ok”
“I send lots money for this and???????? item is not working for me ok”
“Flimsy, very cheap”
“when it literally crumbles in your hand trying to install it, its garbage”
“Definite design flaw”
Top return reasons
Common questions
- Is 16 3/8 x 21 1/2 x1 air filter profitable to sell on Amazon United States?
- The niche generates $302K/yr across 15 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is +39.8%. Flapen's verdict: Worth a look (54/100).
- How competitive is the 16 3/8 x 21 1/2 x1 air filter niche?
- 8 brands and 13 sellers compete. The top 5 products take 70% of clicks and top 5 brands hold 94% of demand.
- What do buyers complain about in 16 3/8 x 21 1/2 x1 air filter?
- Top complaints mined from reviews: Size-Overall, Durability, Filtration. The return rate is 1.6%.
- When does demand for 16 3/8 x 21 1/2 x1 air filter peak?
- Demand peaks in Jun–Jul–Aug; the busiest month runs 2.5× the quietest.
- What does it cost to enter the 16 3/8 x 21 1/2 x1 air filter niche?
- Listings span $32.71–$63.36; the average listing price is $47.80 (sweet spot $15–$100). The average incumbent carries 2,015 reviews — the moat a new listing must climb.