LED vs Halogen Bulbs: Energy, Heat, Lifespan and How to Switch

Updated October 2026 · Meteor Electrical guides · 9 min read

If you are weighing up LED vs halogen for your home lighting, this is the head-to-head comparison. We cover energy use, lumens per watt, heat, lifespan, dimming, colour and the UK halogen phase-out, then explain how to swap GU10 and MR16 halogens for LED bulbs without flicker or compatibility problems.

What is the difference between LED and halogen?

The difference is how each bulb makes light. Both fit the same common caps, such as GU10, MR16, G9, E14 and B22, so they can look almost identical, but they work in very different ways.

What is a halogen bulb?

A halogen bulb is a type of incandescent lamp. A tungsten filament inside a small capsule of halogen gas is heated until it glows. It gives a warm, crisp light at full brightness straight away and is cheap to make, but most of the electricity it uses is turned into heat rather than light, and the filament burns out relatively quickly.

What is an LED bulb?

An LED (light emitting diode) bulb passes current through a semiconductor chip, which emits light directly. A small driver in the lamp converts mains power for the chips, and a heat sink in the body keeps them cool. There is no filament to fail, so LEDs use far less power and last much longer.

LED vs halogen: side-by-side comparison

The table shows typical values for household lamps. Figures vary between brands and products, so always check the packaging or datasheet of the lamp you buy.

For bulb-by-bulb replacements, our LED equivalent wattage chart lists the LED wattage and lumens that match each halogen, incandescent and CFL bulb.

How much energy does LED save compared with halogen?

An LED typically uses around 80 to 90% less electricity than the halogen it replaces. A halogen manages about 12 to 20 lumens per watt; a household LED usually gives about 80 to 150 lumens per watt. So a 5W LED GU10 can give the same light as a 50W halogen GU10.

Compare lumens, not watts

Watts measure the power a bulb uses; lumens measure the light it gives. Because LEDs are so much more efficient, wattage is no longer a guide to brightness. A 50W halogen GU10 gives roughly 350 lumens, so look for an LED GU10 of around 350 to 450 lumens with a similar beam angle.

Working out the saving

You can work out the saving yourself: watts saved ÷ 1,000 × hours per day × 365 gives the kWh saved per year. Multiply that by the unit rate on your electricity bill. The example below uses three hours a day.

Lighting that runs for long hours, such as kitchen spotlights, hallways and outside lights, gives the biggest savings. Our guide to energy saving light bulbs covers LED, halogen and CFL running costs in more detail.

Heat and lifespan: which lasts longer?

Heat

Halogen lamps turn most of the energy they use into heat. A halogen spotlight gets hot enough to burn skin and warms the ceiling void around a downlight. LEDs run much cooler: the base and heat sink feel warm, but there is very little heat in the beam, which is better for comfort, fabrics, artwork and food under kitchen lights.

LEDs still need to lose heat through the body of the lamp. Heat shortens the life of the driver, so avoid fully enclosed fittings unless the lamp is rated for them, and do not cover downlights with loft insulation unless the fitting is designed for it.

Lifespan

A halogen lamp is typically rated at about 2,000 hours. Most household LEDs are rated at about 15,000 to 25,000 hours, and some at more. At three hours a day, 2,000 hours is under two years, while 15,000 hours is well over ten years.

Can you dim LEDs like halogen?

Yes, but only dimmable LEDs, and only with a suitable dimmer. Halogen bulbs dim smoothly on almost any dimmer. LEDs contain electronics, so the lamp and the dimmer have to be compatible:

• Buy lamps marked dimmable. A non-dimmable LED on a dimmer can buzz, flicker or fail early.
• Use an LED-compatible dimmer. Most dimmable LEDs work best on trailing-edge dimmers. Many older leading-edge dimmers were made for halogen.
• Check the load. Old dimmers often have a minimum load of 40W or more. Six 5W LEDs only draw 30W, which may be too little, so check the dimmer’s minimum and maximum LED load.
• Keep to one range. Mixing LED brands on one dimmer can give uneven dimming.

Our guide to installing dimmer switches for LEDs explains dimmer types and loads.

Colour temperature and CRI: does LED look as good as halogen?

Colour temperature

Halogen gives one colour: a warm white of about 2800K to 3000K. LEDs come in a range of colour temperatures, measured in kelvin (K). For a look closest to halogen, choose warm white at 2700K or 3000K.

Colour rendering (CRI)

CRI (colour rendering index) measures how naturally a light shows colours, on a scale up to 100. Halogen scores close to 100, which is why it has a reputation for rich, flattering light. Most household LEDs are CRI 80 or above, which is fine for general lighting. For kitchens, bathroom mirrors, dressing areas and artwork, look for CRI 90 or above.

Other LED advantages

• Instant full brightness in cold lofts, garages and outside lights.
• More robust: no fragile filament to break when knocked.
• Choice of beam angle: narrow beams for accent lighting, wide beams for general light.

Can you still buy halogen bulbs in the UK?

Mostly not. Under ecodesign rules, most halogen bulbs for general household lighting were phased out of sale in Great Britain from September 2021, and most fluorescent lamps followed from 2023. Shops could sell existing stock, and a few specialist types are exempt.

The rules stopped new halogens being placed on the market; they did not make existing ones illegal. You can keep using halogens you already have until they fail. When they do, an LED is the like-for-like replacement, and replacement halogen lamps are becoming harder to find. Northern Ireland and the Republic of Ireland follow EU ecodesign rules, under which most halogen lamps have also been phased out.

How to switch from halogen to LED

For most mains-voltage lamps, switching is a simple bulb swap. Low-voltage MR16 spotlights and dimmed circuits need a little more care.

1. Identify the cap. Check the old bulb or the marking in the fitting: GU10, MR16 (GU5.3), G9, E14, E27 or B22.
2. Match the brightness. Choose by lumens. Around 350 to 450 lumens replaces a 50W halogen GU10.
3. Match the beam angle. About 36° to 40° for general downlighting; 24° or narrower for accent lighting.
4. Pick the colour. 2700K to 3000K for a halogen-like warm white.
5. Check dimming. On a dimmer, buy dimmable LEDs and check the dimmer is LED compatible.
6. Isolate and swap. Switch off, let halogens cool before touching them, then fit the LED.

GU10 halogen to LED

GU10 lamps run directly on 230V mains, so there is no transformer. A GU10 swap is a twist-and-lock bulb change. See our guide to GU10 lamps for lumens, beam angles and dimming.

MR16 halogen to LED: transformer and driver compatibility

MR16 (GU5.3) lamps run on 12V from a transformer or driver in the ceiling. This is where most LED upgrade problems come from:

• Electronic transformers made for halogen often have a minimum load, such as 20W or more. A 4W LED MR16 can fall below it, so the LED flickers, strobes or fails early.
• Old magnetic (wire-wound) transformers can work with some LED MR16s, but check the lamp maker’s compatibility guidance.
• LED drivers. Replacing the transformer with a suitable 12V LED driver matched to the lamp load is usually the reliable fix.
• Convert to GU10. Many people replace 12V MR16 fittings with mains GU10 downlights, which removes the transformer altogether.

Room-by-room tips

• Living rooms and bedrooms: 2700K to 3000K, dimmable, CRI 80 or above.
• Kitchens: 3000K to 4000K with CRI 90 for worktops; check the beam angle covers the counter.
• Bathrooms: use fittings with the right IP rating for the zone; 3000K to 4000K works well at mirrors.
• Hallways and outside: LEDs come on instantly and suit sensors and timers.

LED vs halogen: the verdict

In the LED vs halogen comparison, LED wins for almost every home. It gives the same light for a fraction of the energy, runs cooler, lasts many times longer and offers a choice of colour, and with most halogens phased out it is now the standard replacement. Match the cap, lumens, beam angle and colour, use dimmable LEDs with a compatible dimmer, and check transformers on 12V MR16 fittings.

Need help choosing? Call our team on 028 8675 1515 (048 from ROI), Monday to Friday, 8am–5pm.

FAQs

Is LED better than halogen?

For almost every home use, yes. An LED gives the same light for around 80 to 90% less electricity, runs much cooler and typically lasts 15,000 hours or more against about 2,000 for halogen. Halogen still has excellent colour rendering, but good LEDs with a CRI of 90 or above come very close.

What LED replaces a 50W halogen GU10?

A 50W halogen GU10 gives roughly 350 lumens, so choose an LED GU10 of around 350 to 450 lumens, which is usually about 4W to 6W. Match the beam angle and colour temperature too, and pick a dimmable LED if the light is on a dimmer.

Can I still buy halogen bulbs in the UK?

Most halogen bulbs for general household lighting were phased out of sale in Great Britain from September 2021, with retailers allowed to sell existing stock. A few specialist types are exempt. You can keep using halogens you already have, but LED is now the standard replacement.

Why do my LED bulbs flicker on a dimmer?

Usually because the dimmer was designed for halogen loads. Older leading-edge dimmers often have a minimum load far higher than a few LEDs draw. Use dimmable LEDs with an LED-compatible, usually trailing-edge, dimmer and check its minimum and maximum LED load against the lamps.

Do I need to change the transformer when switching MR16 halogens to LED?

Often, yes. Many 12V transformers were built for 20W to 50W halogen loads, and a 4W LED can fall below their minimum load, causing flicker or failure. Check the transformer is LED compatible, fit a suitable 12V LED driver, or replace the fittings with mains GU10 downlights.

Do LED bulbs get hot?

LEDs get warm, mainly around the base and heat sink, but far less hot than halogen, which turns most of its energy into heat. That makes LEDs more comfortable to live with and safer near insulation and fabrics. They still need ventilation, so avoid fully enclosed fittings unless the lamp is rated for them.

Related guides

• Energy saving light bulbs: LED vs halogen vs CFL
• What are GU10 lamps? GU10 bulbs explained
• LED equivalent wattage chart
• Can I install dimmer switches in my home?