Head-to-Head Comparison
| Metric | LED | Fluorescent |
|---|---|---|
| Typical wattage (4ft tube) | 18W | 36W |
| Lumen output | 2,000–2,400 lm | 2,500–3,200 lm |
| Efficacy (lm/W) | 110–140 lm/W | 70–90 lm/W |
| Lifespan | 50,000+ hours | 10,000–15,000 hours |
| Warm-up time | Instant | 1–3 minutes |
| Contains mercury | No | Yes (disposal required) |
| Flicker | None (quality drivers) | Common (especially ageing) |
| CRI (colour accuracy) | 80–95+ | 70–85 |
| Dimmable | Yes (dimmable models) | Limited, expensive |
| Upfront cost | Higher | Lower |
| Maintenance cost | Very low | High (frequent replacement) |
Real-World Payback Calculation
Here's a worked example for a warehouse with 50 fluorescent fittings (2 × 36W T8 tubes each), running 10 hours per day, 250 days per year:
Example: 50-Fitting Warehouse
Fluorescent annual energy
50 × 72W × 2,500h = 9,000 kWh
LED annual energy
50 × 36W × 2,500h = 4,500 kWh
Annual energy saving
4,500 kWh @ 24p = £1,080/year
LED tube cost (50 fittings × 2)
100 tubes × ~£8 = £800
Payback period
Under 9 months
5-year saving
~£4,600 (energy + maintenance)
Based on UK electricity rate of 24p/kWh. Actual savings will vary.
The Case Against Fluorescent
Mercury disposal
Fluorescent tubes contain mercury and must be disposed of as hazardous waste under UK WEEE regulations. LED contains no hazardous materials.
Flicker and health
Ageing fluorescent tubes flicker at 50–100Hz, which can cause headaches, eye strain and reduced productivity. LED with quality drivers produces no perceptible flicker.
Cold temperature performance
Fluorescent tubes struggle to start in cold environments (below 10°C) and take time to reach full brightness. LED performs consistently from -20°C to +40°C.
Ballast failure
Fluorescent fittings rely on a ballast that degrades over time and is often the first component to fail. LED drivers have a much longer service life.
When Fluorescent Might Still Make Sense
In most cases, LED is the better choice. However, there are limited scenarios where fluorescent may still be considered:
- Very short-term installations where upfront cost is the only consideration
- Specialist applications requiring specific spectral output not yet matched by LED
- Existing fittings with very low hours remaining where replacement is imminent anyway
In all other cases — particularly commercial, industrial and retail applications — LED delivers a better return on investment within 12 months in most scenarios.
Common Questions
How much energy does LED save compared to fluorescent?
LED typically uses 50–60% less energy than equivalent fluorescent lighting. A 36W T8 fluorescent tube can be replaced by an 18W LED tube producing the same or greater lumen output. Over a year of commercial use (3,000 hours), this saves approximately 54 kWh per tube — at current UK electricity rates of around 24p/kWh, that is roughly £13 per tube per year in energy savings alone.
How long do LED lights last compared to fluorescent?
LED lights typically last 50,000 hours or more. Standard T8 fluorescent tubes last around 10,000–15,000 hours. This means an LED fitting will outlast 3–5 fluorescent tubes over its lifetime, significantly reducing replacement and maintenance costs — particularly important in hard-to-reach commercial and industrial installations.
Can I replace fluorescent tubes with LED without rewiring?
Yes, in most cases. Type A LED tubes are plug-and-play replacements that work with the existing fluorescent ballast. Type B LED tubes bypass the ballast and wire directly to mains — this requires an electrician but is more reliable long-term. Type A+B tubes work both ways. Always check the tube length (600mm, 1200mm, 1500mm) and cap type (G13 for T8, G5 for T5) before ordering.