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.

20x21x1 air filter

Skip it

Brand-locked demand (top 5 brands take 97% of clicks) — this niche doesn't clear our bar today.

Returns

Incredible1.0%

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

Good5.7%

search→purchase rate — share of searches ending in a sale

Market size

Bad$97K

$97K/yr · 39K searches

Quality gap

Bad4.7★

avg incumbent rating — lower means beatable quality

Review moat

Bad20,363.15

avg incumbent reviews — the moat a new listing must climb

Competition

Bad82%

top-5 click share — a locked-up shelf

Brand share

Bad97%

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

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

Top-5 brand share

97%

Top 20: 100%

Top-5 click share

82%

Top 20: 100%

Open market

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.

Peak months: Jun, Jul · busiest ÷ quietest = 1.9×

Open Trend

Top 20x21x1 air filter search terms

20x21x1 air filter22K/yr +47.0%4.9% conv.
air filter 20x21x16K/yr +46.7%2.3% conv.
furnace filters 20x21x14K/yr +59.3%0.7% conv.
20x21x1 furnace filter4K/yr +68.8%0.2% conv.
20 x 21 x 1 air filter3K/yr +22.2%6.0% conv.

All 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.

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

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$55.894.7★2,030 rev

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$44.534.7★6,265 rev

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$37.214.7★1,771 rev

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$45.974.7★4,436 rev

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$38.894.7★6,265 rev

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$44.536,265 rev

1y ago

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$18.151 rev

2y ago

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$38.896,265 rev

2y ago

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$37.211,771 rev

3y ago

Simply 20x22x1 Air Filter Merv 8 6 Pack For Home AC Furnace & HVAC (Actual Size: 19.75x21.75x0.75) DUST Pet & Allergy Control

Simply$42.3153,363 rev

4y ago

What buyers say about 20x21x1 air filter

What buyers praise and complain about, mined from review topics.

What buyers love

Value For Money27%

“Good deal”

Filtration20%

“GREAT filters”

Quality-Overall14%

“Good Quality Filters”

Size-Overall12%

“Fits good”

Advertised Vs Actual Product6%

“Work as advertised”

Efficiency4%

“Works well”

Ease Of Use3%

“Easy-peasy”

Strength3%

“Well made and seems more sturdy than some brand name filters I have previously purchased”

Assembly/Installation2%

“easy to install”

Durability1%

“Functional and durable”

What buyers complain about

Filtration22%

“These air filters are not that good”

Quality-Overall21%

“Bad quality”

Strength10%

“Pretty flimsy, I guess theyll do the job”

Size-Overall8%

“Do not fit snug like they are supposed to”

Thickness6%

“Filter is too thick”

Value For Money4%

“the price just keeps going up”

Noise Level3%

“the system became louder a clear sign of poor construction”

Durability2%

“They would only be in my system for 3 weeks and theyd be falling apart when I took them out.”

Thin2%

“Man these feel super thin and flimsy”

Heating2%

“My AC was not cooling properly”

Top return reasons

Size-Overall75%

Filtration13%

Compatibility-Overall4%

Value For Money2%

Quality-Overall1%

Advertised Vs Actual Product1%

Defective Material/Parts1%

Material Quality1%

Functionality-Overall0%

Certifications0%

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.