---
title: "20x21x1 Air Filter — $97K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/tools-home-improvement/20x21x1-air-filter"
last_updated: "2026-08-08T10:22:11.990Z"
locale: en
meta:
description: "Niche score 45/100 · $97K/yr market · 39K searches/yr · $43.55 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 45/100 · $97K/yr market · 39K searches/yr · $43.55 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "20x21x1 Air Filter — $97K/yr Amazon US Niche (2026) - Flapen"
---
# **20x21x1 air filter**
**Skip it**
Brand-locked demand (top 5 brands take 97% of clicks) — this niche doesn't clear our bar today.
Market size 24Growth 68Conversion 64Competition 15Returns 95Price range 88Avg price 95Brand share 8Review moat 16Quality gap 19
**Returns**
**Incredible****1.0%**
return rate — above 5% kills the launch gate
**Avg price**
**Incredible****$43.55**
avg listing price — sweet spot $15–$100
**Price range**
**Great****$18.15–$108.16**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Growth**
**Good****+48.1%**
90-day search growth — must beat 0% to launch
**Conversion**
**Good****5.7%**
search→purchase rate — share of searches ending in a sale
**Market size**
**Bad****$97K**
$97K/yr · 39K searches
**Quality gap**
**Bad****4.7★**
avg incumbent rating — lower means beatable quality
**Review moat**
**Bad****20,363.15**
avg incumbent reviews — the moat a new listing must climb
**Competition**
**Bad****82%**
top-5 click share — a locked-up shelf
**Brand share**
**Bad****97%**
top-5 brand share — brand-locked demand
According to Flapen's Amazon United States niche tracking, 20x21x1 air filter is a $97K/yr Amazon United States market (39K searches/yr). The top 5 brands hold 97% of demand. Demand peaks in Jun–Jul. Verdict: Skip it — 45/100.
Data updated Jul 27, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **20x21x1 air filter market data**
- **Units sold / yr**
- **3K–3K**
- avg 100–250/product
- **Revenue / yr**
- **$109K–$131K**
- units × avg price
- **Conversion rate**
- **5.7%**
- **Avg BSR**
- **#524**
- **Page quality**
- **0%**
- **Prime**
- **54%**
- **Sponsored**
- **77%**
- **Out of stock**
- **10.9%**
- **Avg brand age**
- **83 months**
- **Avg seller age**
- **199 days**
## **Competition & brand share**
The top 5 products capture 82% of clicks — a locked-up shelf that new listings rarely crack.
**Brands**
**7 **▼falling
**Sellers**
**15**
**Top-5 brand share**
**97%**
Top 20: 100%
**Top-5 click share**
**82%**
Top 20: 100%
**Open market**
**1%**
- Filter King62% - Filtrete28% - Simply3% - Enviroflow2% - Generic2% - Amazon Basics2% - Open — no brand owns it (1 brand, 1%)
## **Demand & seasonality**
Weekly Amazon search volume, last 103 weeks — +48.1% search growth over the last 90 days.
1K750Spike '25Prime Day '25Spike '26 seasonDecMarJunAugNovMarMay
Peak months: Jun, Jul · busiest ÷ quietest = 1.9×
[**Open Trend **](https://flapen.com/research/us/tools-home-improvement/20x21x1-air-filter/trend)
## **Top 20x21x1 air filter search terms**
- **20x21x1 air filter**22K/yr+47.0%4.9% conv. - **air filter 20x21x1**6K/yr+46.7%2.3% conv. - **furnace filters 20x21x1**4K/yr+59.3%0.7% conv. - **20x21x1 furnace filter**4K/yr+68.8%0.2% conv. - **20 x 21 x 1 air filter**3K/yr+22.2%6.0% conv. [**All search terms **](https://flapen.com/research/us/tools-home-improvement/20x21x1-air-filter/search-terms)
## **Top 20x21x1 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.
0%10%$10K20%$19K30%$29K40%$39K1101001K10K100K1.0M Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 13 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Filter King 20x21x1 Air Filter (MERV 8) (6-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$55.89**4.7★2,030 rev](https://www.amazon.com/dp/B07HFFDRDW) [2**Filtrete 20x21x1 AC Furnace Air Filter MPR 700 MERV 8 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 4-Pack (Actual Size 19.69 x 20.69 x 0.81 in)**Filtrete**$44.53**4.7★6,265 rev](https://www.amazon.com/dp/B0F9LT2DCT) [3**Filter King 20x21x1 Air Filter (MERV 8) (3-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$37.21**4.7★1,771 rev](https://www.amazon.com/dp/B0BV4PNGV1) [4**Filter King 20x21x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$45.97**4.7★4,436 rev](https://www.amazon.com/dp/B07FQVWP8P) [5**Filtrete 20x21.5x1 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 19.69 x 21.19 x 0.81 in)**Filtrete**$38.89**4.7★6,265 rev](https://www.amazon.com/dp/B0CZBWF3LM)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Filtrete 20x21x1 AC Furnace Air Filter MPR 700 MERV 8 Tough on Pollen Easy on Airflow 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter 4-Pack (Actual Size 19.69 x 20.69 x 0.81 in)**Filtrete**$44.53**6,265 rev1y ago](https://www.amazon.com/dp/B0F9LT2DCT) [**Generic Proairtek AF20211M08SWH Model 20x21x1 Air Filter MERV 8; Ideal for Anyone Wanting Clean Crisp Air in Their Home; Offers Enhanced Airflow and Efficiency; High-performance Filtration**Generic**$18.15**1 rev2y ago](https://www.amazon.com/dp/B0D7GDH2TC) [**Filtrete 20x21.5x1 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 19.69 x 21.19 x 0.81 in)**Filtrete**$38.89**6,265 rev2y ago](https://www.amazon.com/dp/B0CZBWF3LM) [**Filter King 20x21x1 Air Filter (MERV 8) (3-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$37.21**1,771 rev3y ago](https://www.amazon.com/dp/B0BV4PNGV1) [**Simply 20x22x1 Air Filter Merv 8 6 Pack For Home AC Furnace & HVAC (Actual Size: 19.75x21.75x0.75) DUST Pet & Allergy Control**Simply**$42.31**53,363 rev4y ago](https://www.amazon.com/dp/B09RHLPY1Q)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Simply 20x22x1 Air Filter Merv 8 6 Pack For Home AC Furnace & HVAC (Actual Size: 19.75x21.75x0.75) DUST Pet & Allergy Control**Simply**$42.31**4.7★**▲ 99%**](https://www.amazon.com/dp/B09RHLPY1Q) [**Filter King 20x21x1 Air Filter (MERV 8) (12-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$108.16**4.7★**▲ 99%**](https://www.amazon.com/dp/B07HFHHJ7C) [**Filter King 20x21x1 Air Filter (MERV 8) (4-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$45.97**4.7★**▲ 75%**](https://www.amazon.com/dp/B07FQVWP8P) [**Filter King 20x21x1 Air Filter (MERV 8) (6-Pack) Dust & Allergy Control AC Furnace Filters MADE IN USA HVAC Pleated Electrostatic (Actual Size: 20 x 21 x .75)**Filter King**$55.89**4.7★**▲ 58%**](https://www.amazon.com/dp/B07HFFDRDW) [**Amazon Basics 20x20x1 Air Filter 6-Pack MERV 11 AC Furnace Filters Dust Pet Allergy Control Electrostatic (Actual Size: 19.75 x 19.75 x .75)**Amazon Basics**$35.19**4.6★**▲ 18%**](https://www.amazon.com/dp/B088BWBD95)
**~~View all trending →~~**
## **What buyers say about 20x21x1 air filter**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Value For Money**27%
*“Good deal”*
**Filtration**20%
*“GREAT filters”*
**Quality-Overall**14%
*“Good Quality Filters”*
**Size-Overall**12%
*“Fits good”*
**Advertised Vs Actual Product**6%
*“Work as advertised”*
**Efficiency**4%
*“Works well”*
**Ease Of Use**3%
*“Easy-peasy”*
**Strength**3%
*“Well made and seems more sturdy than some brand name filters I have previously purchased”*
**Assembly/Installation**2%
*“easy to install”*
**Durability**1%
*“Functional and durable”*
### **What buyers complain about **
**Filtration**22%
*“These air filters are not that good”*
**Quality-Overall**21%
*“Bad quality”*
**Strength**10%
*“Pretty flimsy, I guess theyll do the job”*
**Size-Overall**8%
*“Do not fit snug like they are supposed to”*
**Thickness**6%
*“Filter is too thick”*
**Value For Money**4%
*“the price just keeps going up”*
**Noise Level**3%
*“the system became louder a clear sign of poor construction”*
**Durability**2%
*“They would only be in my system for 3 weeks and theyd be falling apart when I took them out.”*
**Thin**2%
*“Man these feel super thin and flimsy”*
**Heating**2%
*“My AC was not cooling properly”*
### **Top return reasons **
**Size-Overall**75%
**Filtration**13%
**Compatibility-Overall**4%
**Value For Money**2%
**Quality-Overall**1%
**Advertised Vs Actual Product**1%
**Defective Material/Parts**1%
**Material Quality**1%
**Functionality-Overall**0%
**Certifications**0%
## **Common questions**
- **Is 20x21x1 air filter profitable to sell on Amazon United States?**
- The niche generates $97K/yr across 13 tracked products. 90-day search growth is +48.1%. Flapen's verdict: Skip it (45/100).
- **How competitive is the 20x21x1 air filter niche?**
- 7 brands and 15 sellers compete. The top 5 products take 82% of clicks and top 5 brands hold 97% of demand.
- **What do buyers complain about in 20x21x1 air filter?**
- Top complaints mined from reviews: Filtration, Quality-Overall, Strength. The return rate is 1.0%.
- **When does demand for 20x21x1 air filter peak?**
- Demand peaks in Jun–Jul; the busiest month runs 1.9× the quietest.
- **What does it cost to enter the 20x21x1 air filter niche?**
- Listings span $18.15–$108.16; the average listing price is $43.55 (sweet spot $15–$100). The average incumbent carries 20,363 reviews — the moat a new listing must climb.
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