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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 26.11p/kWh (Ofgem Q3 2026):
| 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 | £477 | £48 |
| Bulb replacements/year | ~7 bulbs (£14) | ~0.5 bulbs (£3) |
| Total annual cost | £491 | £51 |
| Annual saving with LED | £440/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 223 kg of CO2 (DESNZ 2024 grid factor 136g/kWh). 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
Next up: related pages
How We Calculate This
Frequently Asked Questions
LEDs use 80-85% less electricity than halogen for the same light output. A 50W halogen GU10 is replaced by a 5W LED GU10 producing the same 350-400 lumens. For a home with 20 downlights running 5 hours per day, switching from halogen to LED saves about £430 per year in electricity at 26.11p/kWh (Ofgem Q3 2026).
Most halogen bulbs were banned from sale in the UK from September 2021 under the Ecodesign Directive. Linear halogen tubes (R7s) and some specialist types remain available. If you have halogen fittings, LED replacements are available in all common cap types (GU10, GU5.3, E27, E14, B22, G9, G4).
Not always. Standard halogen dimmers have a minimum load of 25-60W, which may be higher than the total LED load (e.g., 4 x 5W = 20W). This causes flickering, buzzing or failure to dim. Use an LED-compatible dimmer (Varilight V-Pro, Hamilton Litestat, etc.) with a minimum load of 0-5W. LED dimmers also have a maximum VA rating.
Yes, in most ceiling installations. LED downlights must maintain the fire resistance of the ceiling (typically 30 minutes). Fire-rated LED downlights have an intumescent pad that expands in heat to seal the hole. This is a Building Regulations requirement (Part B). Non-fire-rated downlights are only suitable for ground floor ceilings with no room above.
For UK homes: 2700K (warm white) suits living rooms and bedrooms, replicating traditional bulb warmth. 3000K (neutral warm) suits kitchens and bathrooms. 4000K (cool white) suits garages and utility areas. 6500K (daylight) is too harsh for most domestic settings. Halogen is naturally 2800-3000K.
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Last updated: July 2026
Verified against UK standards · estimates only, confirm with your supplier.