FAQ
TL;DR: Swapping a 36 W fluorescent for an 18 W LED tube can cut real load by ≈2 W per fitting [Elektroda, zett1, post #18278838] “LED circuits do not need any starters” [Elektroda, Xantix, post #16887970] Bypass the magnetic ballast for best efficiency.
Why it matters: Simple rewiring delivers instant energy savings, longer lamp life and lower maintenance.
Quick Facts
• Magnetic ballast losses: Typical 2-6 W per fitting [Osram Data, 2023].
• LED “starter” cost: PLN 2–5 per piece [Elektroda, zett1, post #17706520]
• Lumen output: 18 W T8 LED ≈ 1800–2000 lm (100-110 lm/W) [Osram Data, 2023].
• Retrofit time: ≈2 min when using LED starter; ≈5 min when bypassing ballast [Author calc].
• Safety standard: IEC 62776 covers double-capped LED retrofit tubes [IEC, 2014].
Do LED tubes actually need a starter?
No. LED drivers ignite instantly, so a classic glow-starter is useless. Manufacturers bundle a so-called “LED starter” only to bridge the circuit when you keep the magnetic ballast [Elektroda, Xantix, post #16887970]
What is inside an “LED starter”?
Usually a simple fuse or solid jumper rated about 2 A. It completes the circuit so both tube pins receive mains when the ballast stays in place [Elektroda, zett1, post #17706654]
Can I leave the magnetic ballast connected?
Yes, the lamp lights, but the ballast wastes 2-6 W and adds failure points. Bypassing it maximises savings and removes buzzing [Elektroda, zett1, post #18278838]
How do I bypass a magnetic ballast safely?
- Isolate power and verify zero volts. 2. Remove ballast leads and join live to the lampholder pin on the powered side; join neutral to the other pin. 3. Remove any power-factor capacitor. Fit tube, restore power. Work takes under 5 minutes [How-To derived from thread].
What happens if I keep the compensating capacitor?
Reactive energy can rise, inflating bills in metered installations. Some makers warn to disconnect the capacitor for that reason [Elektroda, zett1, post #17706654]
Are LED tubes compatible with electronic ballasts?
Most retrofits are NOT; they require direct 230 V. Always check the datasheet. Using an incompatible electronic ballast may destroy the tube or ballast [Osram SubstiTUBE Guide, 2023].
Will light output drop when I replace 36 W fluorescent with 18 W LED?
Modern 18 W LEDs deliver around 1900 lm vs 2800 lm from a fresh 36 W T8. Many workplaces still meet lux targets because fluorescent output falls 20-30 % within 2000 h, while LEDs stay stable longer [Osram Data, 2023].
What is the expected lifespan of retrofit tubes?
Rated life is 30,000–50,000 h (L70), equal to 10–15 years at 10 h/day. Forum users report some budget tubes failing in 3 years due to heat build-up [Elektroda, Strumien…, #18285270].
Edge case: can the fuse in an LED starter blow?
Yes. A ballast short or wiring error can pop the 2 A fuse, darkening the lamp. Replace the fuse or bypass ballast to restore operation [Elektroda, HD-VIDEO, post #17708084]
Does reactive power from LEDs matter in small installs?
With 4.5 kW of LED load, power factor typically >0.9, so extra reactive power is minimal and rarely penalised by utilities [Elektroda, opornik7, post #18301273]
Why do some users report shorter LED life than fluorescents?
Poor thermal design traps the 18 W of heat inside the tube. Over-temperature halves LED lifetime. Choose metal-back tubes and avoid closed fixtures [Elektroda, BikeBarian, post #18285320]
Can I DIY an LED starter from a traditional one?
Yes. Remove the neon and capacitor, twist the two internal leads together, or solder a 2 A glass fuse across them [Elektroda, kierbedz4, post #18300544]
