---
title: "F13t5cw Fluorescent Bulbs 21 Inch — $122K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/tools-home-improvement/f13t5cw-fluorescent-bulbs-21-inch"
last_updated: "2026-08-09T03:18:00.341Z"
locale: en
meta:
description: "Niche score 45/100 · $122K/yr market · 41K searches/yr · $21.44 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 45/100 · $122K/yr market · 41K searches/yr · $21.44 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "F13t5cw Fluorescent Bulbs 21 Inch — $122K/yr Amazon US Niche (2026) - Flapen"
---
# **f13t5cw fluorescent bulbs 21 inch**
**Skip it**
Soft demand (-15.9% this quarter) — this niche doesn't clear our bar today.
Market size 28Growth 17Conversion 96Competition 30Returns 42Price range 79Avg price 91Brand share 24Review moat 63Quality gap 57
**Conversion**
**Incredible****14.0%**
search→purchase rate — share of searches ending in a sale
**Avg price**
**Great****$21.44**
avg listing price — sweet spot $15–$100
**Price range**
**Great****$12.70–$24.57**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Review moat**
**Good****991.64**
avg incumbent reviews — the moat a new listing must climb
**Quality gap**
**Good****4.4★**
avg incumbent rating — lower means beatable quality
**Returns**
**Okay****3.6%**
return rate — above 5% kills the launch gate
**Competition**
**Okay****67%**
top-5 click share — leaders hold, buyers still browse
**Market size**
**Okay****$122K**
$122K/yr · 41K searches
**Brand share**
**Bad****90%**
top-5 brand share — brand-locked demand
**Growth**
**Bad****-15.9%**
90-day search growth — must beat 0% to launch
According to Flapen's Amazon United States niche tracking, f13t5cw fluorescent bulbs 21 inch is a $122K/yr Amazon United States market (41K searches/yr). The top 5 brands hold 90% of demand. Demand peaks in Jan. Verdict: Skip it — 45/100.
Data updated Jul 28, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **f13t5cw fluorescent bulbs 21 inch market data**
- **Units sold / yr**
- **5K–6K**
- avg 250–500/product
- **Revenue / yr**
- **$107K–$129K**
- units × avg price
- **Conversion rate**
- **14.0%**
- **Avg BSR**
- **#478**
- **Page quality**
- **0%**
- **Prime**
- **93%**
- **Sponsored**
- **93%**
- **Out of stock**
- **0.0%**
- **Avg brand age**
- **115 months**
- **Avg seller age**
- **190 days**
## **Competition & brand share**
The top 5 products take 67% of clicks — established leaders, but buyers still shop beyond them.
**Brands**
**8 **▼falling
**Sellers**
**15**
**Top-5 brand share**
**90%**
Top 20: 100%
**Top-5 click share**
**67%**
Top 20: 100%
**Open market**
**4%**
- Circle37% - Unique Bulbs19% - Konideke18% - KOR10% - BULBMASTER7% - Wesome Lighting5% - Open — no brand owns it (2 brands, 4%)
## **Demand & seasonality**
Weekly Amazon search volume, last 104 weeks — -15.9% search growth over the last 90 days.
1K600Spike '24Black Friday '24Spike '25Holiday '25Spike '26 seasonSepDecMarJunAugNovMarMay
Peak months: Jan · busiest ÷ quietest = 1.9×
[**Open Trend **](https://flapen.com/research/us/tools-home-improvement/f13t5cw-fluorescent-bulbs-21-inch/trend)
## **Top f13t5cw fluorescent bulbs 21 inch search terms**
- **f13t5cw fluorescent bulbs 21 inch**14K/yr-3.5%14.3% conv. - **f13t5**9K/yr-2.7%8.5% conv. - **f13t5cw**5K/yr-13.1%15.3% conv. - **f13t5 bulb**3K/yr-16.2%7.8% conv. - **f13t5cw led replacement**8K/yr-69.3%7.5% conv. [**All search terms **](https://flapen.com/research/us/tools-home-improvement/f13t5cw-fluorescent-bulbs-21-inch/search-terms)
## **Top f13t5cw fluorescent bulbs 21 inch 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%$12K20%$24K30%$37K40%$49K101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 14 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Circle (6 Pack) F13T5/CW - T5 Fluorescent 4100K Cool White - 21 Linear - 13 Watt T5 - Under the Counter Light Bulbs**Circle**$23.78**4.5★1,844 rev](https://www.amazon.com/dp/B01EDMZNI4) [2**Unique Bulbs (Pack of 2) F13T5/CW 13-Watt T5 Fluorescent Cool White 4100K Super Long Life**Unique Bulbs**$17.49**4.4★1,927 rev](https://www.amazon.com/dp/B00K1E5RK8) [3**KOR (Pack of 6) F13T5/CW - T5 Fluorescent 4100K Cool White - 13 Watt - 21 Super Long Life Light Bulbs**KOR**$22.70**4.5★3,537 rev](https://www.amazon.com/dp/B00TJ6XL3Y) [4**Konideke (4 Set) F8T5/CW 8 Watt and F13T5/CW 13 Watt T5 12 Inches 8W and 21 Inches 13W Under Counter Fluorescent Light Bulbs Cool White 4100K G5 Cap**Konideke**$24.57**4.8★36 rev](https://www.amazon.com/dp/B0FQ22XKWZ) [5**8 Pack 21 Inch T5 Fluorescent Light Bulb 13 Watt F13T5/CW Compatible for Sylvania Satco Philips GE Under Cabinet Tube Light Cool White 800 Lumen G5 Base 8 Count**Konideke**$24.30**4.5★181 rev](https://www.amazon.com/dp/B0CNQY7Z6T)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Konideke (4 Set) F8T5/CW 8 Watt and F13T5/CW 13 Watt T5 12 Inches 8W and 21 Inches 13W Under Counter Fluorescent Light Bulbs Cool White 4100K G5 Cap**Konideke**$24.57**36 rev10mo ago](https://www.amazon.com/dp/B0FQ22XKWZ) [**Wesome Lighting 12 inch F8T5 and 21 inch F13T5 Warm White Set LED Replacement Bulbs 3000K Replace Fluorescent Bulb with LED Replacement Tube for Counter and Cabinet Fixture**Wesome Lighting**$20.24**24 rev1y ago](https://www.amazon.com/dp/B0DZWR9YBC) [**Wesome Lighting 21 Inch F13T5/CW LED Replacement Bulbs 4100K Cool White T5 LED 9 Watts Replace Fluorescent Bulb with LED Replacement Tube for Counter and Cabinet Fixture 4 Pack**Wesome Lighting**$24.49**84 rev2y ago](https://www.amazon.com/dp/B0D5H63RJP) [**8 Pack 21 Inch T5 Fluorescent Light Bulb 13 Watt F13T5/CW Compatible for Sylvania Satco Philips GE Under Cabinet Tube Light Cool White 800 Lumen G5 Base 8 Count**Konideke**$24.30**181 rev2y ago](https://www.amazon.com/dp/B0CNQY7Z6T) [**8 Pack 21 Inch T5 Fluorescent Light Bulb 13 Watt F13T5/WW Compatible with Sylvania Satco Philips GE Under Cabinet Tube Light Warm White 800 Lumen G5 Base 8 Count**Konideke**$23.53**223 rev2y ago](https://www.amazon.com/dp/B0CKMVBMC6)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Konideke (4 Set) F8T5/CW 8 Watt and F13T5/CW 13 Watt T5 12 Inches 8W and 21 Inches 13W Under Counter Fluorescent Light Bulbs Cool White 4100K G5 Cap**Konideke**$24.57**4.8★**▲ 154%**](https://www.amazon.com/dp/B0FQ22XKWZ) [**Circle (6 Pack) F13T5/WW - T5 Fluorescent 3000K Warm White - 21 Linear - 13 Watt T5 - Under The Counter Light Bulbs**Circle**$22.99**4.5★**▲ 51%**](https://www.amazon.com/dp/B01EDN88QW) [**BULBMASTER F13T5/CW Fluorescent Bulbs 21 Inch 13 Watt T5 Fluorescent Light Bulb - 21 Linear T5 4100K - Under The Counter Kitchen Light Bulbs - Cool White - Pack of 6**BULBMASTER**$21.58**4.2★**▲ 40%**](https://www.amazon.com/dp/B0DXCV86RT) [**Unique Bulbs 2 Pack F13T5/WW 13W T5 21 Warm White 3000k Fluorescent Light Bulb 20 000hr**Unique Bulbs**$17.46**4.4★**▲ 29%**](https://www.amazon.com/dp/B00K0PQC3E) [**Unique Bulbs (Pack of 2) F13T5/CW 13-Watt T5 Fluorescent Cool White 4100K Super Long Life**Unique Bulbs**$17.49**4.4★**▲ 14%**](https://www.amazon.com/dp/B00K1E5RK8)
**~~View all trending →~~**
## **What buyers say about f13t5cw fluorescent bulbs 21 inch**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Size-Overall**20%
*“Fit fine”*
**Advertised Vs Actual Product**19%
*“Just as advertised”*
**Value For Money**15%
*“Good deal”*
**Brightness/Shine/Glow**13%
*“the brightness is excellent”*
**Quality-Overall**9%
*“Excellent product”*
**Color**5%
*“Nice warm color”*
**Efficiency**4%
*“Works great”*
**Assembly/Installation**3%
*“Easy to install”*
**Bulb Flicker/Dimming/Color**2%
*“The first bulb I installed is working well, the color and brightness match our current under counter lamps”*
**Functionality-Overall**1%
*“Work great and fit just right with my old under cabinet lights”*
### **What buyers complain about **
**Bulb Flicker/Dimming/Color**21%
*“I installed a bulb from this pack, put the shade thing on, flipped the switch, and the bulb just flashed and flickered off and on and even buzzed”*
**Size-Overall**11%
*“Fitment was mixed”*
**Durability**10%
*“They dont last”*
**Quality-Overall**9%
*“so I don't have a lot of confidence in the quality of these bulbs”*
**Functionality-Overall**9%
*“didn't work”*
**Compatibility-Overall**4%
*“don't work with my ballasts”*
**Noise Level**4%
*“you can hear a tinkling sound when you move them”*
**Defective Material/Parts**4%
*“Does not fit the light unit due to this defect”*
**Flammable**3%
*“one of the bulbs came dead and flickering, tried in several sockets”*
**Advertised Vs Actual Product**2%
*“Not as pictured”*
### **Top return reasons **
**Size-Overall**33%
**Bulb Flicker/Dimming/Color**19%
**Color**12%
**Defective Material/Parts**8%
**Functionality-Overall**6%
**Advertised Vs Actual Product**6%
**Brightness/Shine/Glow**5%
**Compatibility-Overall**4%
**Noise Level**1%
**Value For Money**1%
## **Common questions**
- **Is f13t5cw fluorescent bulbs 21 inch profitable to sell on Amazon United States?**
- The niche generates $122K/yr across 14 tracked products. 1 of 1 products launched in the last 360 days are still selling. 90-day search growth is -15.9%. Flapen's verdict: Skip it (45/100).
- **How competitive is the f13t5cw fluorescent bulbs 21 inch niche?**
- 8 brands and 15 sellers compete. The top 5 products take 67% of clicks and top 5 brands hold 90% of demand.
- **What do buyers complain about in f13t5cw fluorescent bulbs 21 inch?**
- Top complaints mined from reviews: Bulb Flicker/Dimming/Color, Size-Overall, Durability. The return rate is 3.6%.
- **When does demand for f13t5cw fluorescent bulbs 21 inch peak?**
- Demand peaks in Jan; the busiest month runs 1.9× the quietest.
- **What does it cost to enter the f13t5cw fluorescent bulbs 21 inch niche?**
- Listings span $12.70–$24.57; the average listing price is $21.44 (sweet spot $15–$100). The average incumbent carries 992 reviews — the moat a new listing must climb.
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