LED vs Halogen Lighting — UK Energy Guide
Comparing LED and halogen lighting — power consumption, lifespan, colour temperature, dimming compatibility and energy cost savings.
Side-by-Side Comparison
| Property | LED | Halogen |
|---|---|---|
| Power (equiv. 50W halogen) | 5-7W | 50W |
| Lumens (typical GU10) | 350-400 lm | 350-400 lm |
| Efficacy (lm/W) | 70-130 lm/W | 15-20 lm/W |
| Lifespan | 15,000-50,000 hours | 2,000-3,000 hours |
| Cost per bulb | £2-8 | £1-3 (where available) |
| Annual cost per bulb (5hrs/day) | £2.50-3.50 | £23-25 |
| Heat output | Low — cool to touch | Very hot (250-350°C surface) |
| Colour temperature | 2700-6500K (selectable) | 2800-3000K (fixed) |
| CRI (Colour Rendering) | 80-98 (varies by quality) | 100 (perfect) |
| Dimmable | Yes (needs LED dimmer) | Yes (any dimmer) |
Energy Cost Savings
For a typical UK home with 20 downlights, running 5 hours per day at 25p/kWh:
| Metric | Halogen (20 x 50W) | LED (20 x 5W) |
|---|---|---|
| Total wattage | 1,000W | 100W |
| Daily consumption | 5 kWh | 0.5 kWh |
| Annual consumption | 1,825 kWh | 182.5 kWh |
| Annual electricity cost | £456 | £46 |
| Bulb replacements/year | ~7 bulbs (£14) | ~0.5 bulbs (£3) |
| Total annual cost | £470 | £49 |
| Annual saving with LED | £421/year | |
When to Choose Each
Choose LED (Almost Always)
- Every new installation
- Replacing halogen downlights
- Where heat is a concern (insulation contact)
- High-use areas (kitchens, hallways)
- Smart home integration (colour changing)
Halogen May Still Suit
- Specialist fittings (oven lights, some R7s)
- Where CRI 100 is critical (art galleries)
- Very rarely used lights (cost not a factor)
- Legacy fittings where LED does not fit
Environmental Considerations
Switching 20 halogen downlights to LED saves about 1,640 kWh per year — equivalent to 300 kg of CO2. LED bulbs last 10-15 times longer, generating far less waste. While LED bulbs contain small amounts of electronic components, their energy savings over their lifetime far outweigh the manufacturing impact. LEDs are WEEE-classified and should be recycled at local recycling centres.
Related Calculators
- Lighting Layout Calculator — plan lighting by room and lux level
- Lux Level Calculator — calculate fitting count from CIBSE lux tables
How We Calculate This
Frequently Asked Questions
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Last updated: April 2026
All calculations are estimates. Verify with your supplier.