f13t5cw fluorescent bulbs 21 inch
Skip itSoft demand (-15.9% this quarter) — this niche doesn't clear our bar today.
Conversion
Incredible14.0%search→purchase rate — share of searches ending in a sale
Avg price
Great$21.44avg listing price — sweet spot $15–$100
Price range
Great$12.70–$24.57cheapest to priciest tracked listing — scored on the share inside $15–$100
Review moat
Good991.64avg incumbent reviews — the moat a new listing must climb
Quality gap
Good4.4★avg incumbent rating — lower means beatable quality
Returns
Okay3.6%return rate — above 5% kills the launch gate
Competition
Okay67%top-5 click share — leaders hold, buyers still browse
Market size
Okay$122K$122K/yr · 41K searches
Brand share
Bad90%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
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.Peak months: Jan · busiest ÷ quietest = 1.9×
Top f13t5cw fluorescent bulbs 21 inch search terms
- f13t5cw fluorescent bulbs 21 inch14K/yr
- f13t59K/yr
- f13t5cw5K/yr
- f13t5 bulb3K/yr
- f13t5cw led replacement8K/yr
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.
All 14 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Circle (6 Pack) F13T5/CW - T5 Fluorescent 4100K Cool White - 21 Linear - 13 Watt T5 - Under the Counter Light Bulbs
Circle$23.784.5★1,844 rev
Unique Bulbs (Pack of 2) F13T5/CW 13-Watt T5 Fluorescent Cool White 4100K Super Long Life
Unique Bulbs$17.494.4★1,927 rev
KOR (Pack of 6) F13T5/CW - T5 Fluorescent 4100K Cool White - 13 Watt - 21 Super Long Life Light Bulbs
KOR$22.704.5★3,537 rev
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$24.574.8★36 rev
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$24.304.5★181 rev
Newest
by launch dateKonideke (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$24.5736 rev
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$20.2424 rev
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$24.4984 rev
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$24.30181 rev
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$23.53223 rev
Trending
90-day click momentumKonideke (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$24.574.8★
Circle (6 Pack) F13T5/WW - T5 Fluorescent 3000K Warm White - 21 Linear - 13 Watt T5 - Under The Counter Light Bulbs
Circle$22.994.5★
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$21.584.2★
Unique Bulbs 2 Pack F13T5/WW 13W T5 21 Warm White 3000k Fluorescent Light Bulb 20 000hr
Unique Bulbs$17.464.4★
Unique Bulbs (Pack of 2) F13T5/CW 13-Watt T5 Fluorescent Cool White 4100K Super Long Life
Unique Bulbs$17.494.4★
What buyers say about f13t5cw fluorescent bulbs 21 inch
What buyers praise and complain about, mined from review topics.What buyers love
“Fit fine”
“Just as advertised”
“Good deal”
“the brightness is excellent”
“Excellent product”
“Nice warm color”
“Works great”
“Easy to install”
“The first bulb I installed is working well, the color and brightness match our current under counter lamps”
“Work great and fit just right with my old under cabinet lights”
What buyers complain about
“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”
“Fitment was mixed”
“They dont last”
“so I don't have a lot of confidence in the quality of these bulbs”
“didn't work”
“don't work with my ballasts”
“you can hear a tinkling sound when you move them”
“Does not fit the light unit due to this defect”
“one of the bulbs came dead and flickering, tried in several sockets”
“Not as pictured”
Top return reasons
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.