---
title: "Reviews — 16x21x1 air filters - Flapen"
canonical_url: "https://flapen.com/research/us/tools-home-improvement/16x21x1-air-filters/reviews"
last_updated: "2026-08-06T04:38:35.069Z"
locale: en
meta:
  description: "Niche score 58/100 · $361K/yr market. A failed launch gate (market size, growth, or returns) keeps it on the watch list. Data updated Jul 2026."
  "og:description": "Niche score 58/100 · $361K/yr market. A failed launch gate (market size, growth, or returns) keeps it on the watch list. Data updated Jul 2026."
  "og:title": "Reviews — 16x21x1 air filters - Flapen"
---

# **16x21x1 air filters**

**Worth a look**

Shows a sweet-spot price point ($44.79 avg), but a failed launch gate (market size, growth, or returns) keeps it on the watch list.

Market size 54Growth 64Conversion 88Competition 45Returns 90Price range 95Avg price 95Brand share 28Review moat 24Quality gap 20

**Avg price**

**Incredible****$44.79**

avg listing price — sweet spot $15–$100

**Price range**

**Incredible****$25.59–$63.36**

cheapest to priciest tracked listing — scored on the share inside $15–$100

**Returns**

**Great****1.3%**

return rate — above 5% kills the launch gate

**Conversion**

**Great****10.3%**

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

**Growth**

**Good****+41.8%**

90-day search growth — must beat 0% to launch

**Market size**

**Good****$361K**

$361K/yr · 78K searches

**Competition**

**Okay****58%**

top-5 click share — leaders hold, buyers still browse

**Brand share**

**Okay****88%**

top-5 brand share — brands hold most of the demand

**Review moat**

**Bad****6,282.52**

avg incumbent reviews — the moat a new listing must climb

**Quality gap**

**Bad****4.7★**

avg incumbent rating — lower means beatable quality

## Reviews