---
title: "Air Filter 21.5 X 23.5 X 1 — $40K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/tools-home-improvement/air-filter-21-5-x-23-5-x-1"
last_updated: "2026-08-08T14:27:45.363Z"
locale: en
meta:
description: "Niche score 42/100 · $40K/yr market · 15K searches/yr · $54.22 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 42/100 · $40K/yr market · 15K searches/yr · $54.22 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "Air Filter 21.5 X 23.5 X 1 — $40K/yr Amazon US Niche (2026) - Flapen"
---
# **air filter 21.5 x 23.5 x 1**
**Skip it**
Brand-locked demand (top 5 brands take 100% of clicks) — this niche doesn't clear our bar today.
Market size 10Growth 78Conversion 58Competition 4Returns 87Price range 95Avg price 92Brand share 0Review moat 43Quality gap 21
**Price range**
**Incredible****$41.54–$75.50**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Avg price**
**Great****$54.22**
avg listing price — sweet spot $15–$100
**Returns**
**Great****1.4%**
return rate — above 5% kills the launch gate
**Growth**
**Great****+68.2%**
90-day search growth — must beat 0% to launch
**Conversion**
**Good****4.9%**
search→purchase rate — share of searches ending in a sale
**Review moat**
**Okay****2,164.57**
avg incumbent reviews — the moat a new listing must climb
**Quality gap**
**Bad****4.7★**
avg incumbent rating — lower means beatable quality
**Market size**
**Bad****$40K**
$40K/yr · 15K searches
**Competition**
**Bad****95%**
top-5 click share — a locked-up shelf
**Brand share**
**Bad****100%**
top-5 brand share — brand-locked demand
**Signals**[** High Price**](https://flapen.com/research/niches?market=us&signal=high_price "Avg price > $50")
According to Flapen's Amazon United States niche tracking, air filter 21.5 x 23.5 x 1 is a $40K/yr Amazon United States market (15K searches/yr). The top 5 brands hold 100% of demand. Demand peaks in Jun–Jul. Verdict: Skip it — 42/100.
Data updated Jul 27, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **air filter 21.5 x 23.5 x 1 market data**
- **Units sold / yr**
- **1K–2K**
- avg 100–250/product
- **Revenue / yr**
- **$68K–$81K**
- units × avg price
- **Conversion rate**
- **4.9%**
- **Avg BSR**
- **#156**
- **Page quality**
- **0%**
- **Prime**
- **43%**
- **Sponsored**
- **71%**
- **Out of stock**
- **0.0%**
- **Avg brand age**
- **90 months**
- **Avg seller age**
- **239 days**
## **Competition & brand share**
The top 5 products capture 95% of clicks — a locked-up shelf that new listings rarely crack.
**Brands**
**3 **▼falling
**Sellers**
**7**
**Top-5 brand share**
**100%**
Top 20: 100%
**Top-5 click share**
**95%**
Top 20: 100%
**Open market**
**0%**
- Filter King54% - Filtrete41% - Aerostar5%
## **Demand & seasonality**
Weekly Amazon search volume, last 102 weeks — +68.2% search growth over the last 90 days.
500300Spike '25Black Friday '25Spike '26 seasonDecMarJunAugNovMarMay
Peak months: Jun, Jul · busiest ÷ quietest = 2.6×
[**Open Trend **](https://flapen.com/research/us/tools-home-improvement/air-filter-21-5-x-23-5-x-1/trend)
## **Top air filter 21.5 x 23.5 x 1 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%15%$6K30%$12K45%$18K60%$24K1001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 7 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Filter King 21.5x23.5x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5x23.5x.75)**Filter King**$41.54**4.7★1,569 rev](https://www.amazon.com/dp/B0BJ48V76J) [2**Filtrete 21.5x23.5x1 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 21.19 x 23.19 x 0.81 in)**Filtrete**$43.54**4.7★6,265 rev](https://www.amazon.com/dp/B0CZBXGD2H) [3**Filter King 21.5x23.5x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5 x 23.5 x .75)**Filter King**$46.30**4.7★4,436 rev](https://www.amazon.com/dp/B0BMGZF2BR) [4**Filtrete 21.5x23x1 AC Furnace Air Filter MPR 700 MERV 8 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 6-Pack (Actual Size 21.19 x 22.69 x 0.81 in)**Filtrete**$47.13**4.6★627 rev](https://www.amazon.com/dp/B0DMTH2LCD) [5**Aerostar 21 1/2x23 1/2x1 MERV 11 High Efficiency Pleated Air Filter 6-Pack Electrostatic AC Furnace HVAC Replacement Captures Dust Pollen Pet Dander Mold Smoke (21.5x23.5x0.75)**Aerostar**$75.50**4.6★106 rev](https://www.amazon.com/dp/B01CR9JIJU)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Filtrete 21.5x23x1 AC Furnace Air Filter MPR 700 MERV 8 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 6-Pack (Actual Size 21.19 x 22.69 x 0.81 in)**Filtrete**$47.13**627 rev1y ago](https://www.amazon.com/dp/B0DMTH2LCD) [**Filter King 21.5x23.5x1 Air Filter (MERV 8) (6-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5 x 23.5 x .75)**Filter King**$62.91**2,030 rev1y ago](https://www.amazon.com/dp/B0DPJGG54D) [**Filtrete 21.5x23.5x1 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 21.19 x 23.19 x 0.81 in)**Filtrete**$43.54**6,265 rev2y ago](https://www.amazon.com/dp/B0CZBXGD2H) [**Aerostar 21.5x23.3125x1 MERV 8-6 Count - High Efficiency Pleated HVAC Furnace & Air Conditioner Filters - Removes Dust Lint Mold & Allergy-Causing Pollen**Aerostar**$62.61**119 rev3y ago](https://www.amazon.com/dp/B0BSNZVB9D) [**Filter King 21.5x23.5x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5 x 23.5 x .75)**Filter King**$46.30**4,436 rev3y ago](https://www.amazon.com/dp/B0BMGZF2BR)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Filter King 21.5x23.5x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5x23.5x.75)**Filter King**$41.54**4.7★**▲ 99%**](https://www.amazon.com/dp/B0BJ48V76J) [**Aerostar 21 1/2x23 1/2x1 MERV 11 High Efficiency Pleated Air Filter 6-Pack Electrostatic AC Furnace HVAC Replacement Captures Dust Pollen Pet Dander Mold Smoke (21.5x23.5x0.75)**Aerostar**$75.50**4.6★**▲ 39%**](https://www.amazon.com/dp/B01CR9JIJU) [**Filter King 21.5x23.5x1 Air Filter (MERV 8) (6-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5 x 23.5 x .75)**Filter King**$62.91**4.7★**▲ 38%**](https://www.amazon.com/dp/B0DPJGG54D) [**Filtrete 21.5x23x1 AC Furnace Air Filter MPR 700 MERV 8 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 6-Pack (Actual Size 21.19 x 22.69 x 0.81 in)**Filtrete**$47.13**4.6★**— 1%**](https://www.amazon.com/dp/B0DMTH2LCD) [**Filter King 21.5x23.5x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 21.5 x 23.5 x .75)**Filter King**$46.30**4.7★**▼ 16%**](https://www.amazon.com/dp/B0BMGZF2BR)
**~~View all trending →~~**
## **What buyers say about air filter 21.5 x 23.5 x 1**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Quality-Overall**47%
*“The service and filters are of great quality”*
**Ease Of Use**20%
*“Useful”*
**Advertised Vs Actual Product**12%
*“Does the job”*
**Value For Money**7%
*“worth it for me”*
**Filtration**5%
*“The filtering material seems great”*
### **What buyers complain about **
**Quality-Overall**17%
*“Very low quality”*
**Material Quality**17%
*“Very low quality material”*
**Value For Money**17%
*“Not what I expected for the price”*
**Design-Overall**13%
*“flimsy construction”*
**Flexibility**13%
*“sometimes it bends”*
### **Top return reasons **
**Size-Overall**74%
**Filtration**16%
**Compatibility-Overall**6%
**Value For Money**1%
**Thin**1%
**Advertised Vs Actual Product**1%
**Durability**0%
**Material Quality**0%
**Mechanism Issues**0%
**Defective Material/Parts**0%
## **Common questions**
- **Is air filter 21.5 x 23.5 x 1 profitable to sell on Amazon United States?**
- The niche generates $40K/yr across 7 tracked products. 90-day search growth is +68.2%. Flapen's verdict: Skip it (42/100).
- **How competitive is the air filter 21.5 x 23.5 x 1 niche?**
- 3 brands and 7 sellers compete. The top 5 products take 95% of clicks and top 5 brands hold 100% of demand.
- **What do buyers complain about in air filter 21.5 x 23.5 x 1?**
- Top complaints mined from reviews: Quality-Overall, Material Quality, Value For Money. The return rate is 1.4%.
- **When does demand for air filter 21.5 x 23.5 x 1 peak?**
- Demand peaks in Jun–Jul; the busiest month runs 2.6× the quietest.
- **What does it cost to enter the air filter 21.5 x 23.5 x 1 niche?**
- Listings span $41.54–$75.50; the average listing price is $54.22 (sweet spot $15–$100). The average incumbent carries 2,165 reviews — the moat a new listing must climb.
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