Switching to LED lighting: the complete guide

Lighting is one of the easiest energy wins in any home. The technology has matured — modern LEDs are bright, warm and last for years. The main job is choosing the right one for each fitting.

Why LEDs are worth switching to

Incandescent bulbs work by heating a wire until it glows. That is spectacularly inefficient — most of the energy leaves as heat, not light. Halogen bulbs are a step better but still waste most of their energy the same way. LEDs (light-emitting diodes) work differently: they pass current through a semiconductor, which produces light directly and with far less wasted heat.

In practical terms this means:

• Energy use drops dramatically. An LED producing the same amount of light as a 60-watt incandescent typically draws around 8–10 watts — roughly an 80–85% reduction in electricity for that fitting.
• They last far longer. A decent LED is typically rated for 15,000–25,000 hours, compared with around 1,000 hours for a standard incandescent. You replace them far less often.
• The payback is quick. Because they run for so many hours and use so little power, LEDs pay back their small purchase price through lower bills relatively quickly — especially for lights you use a lot. After that, the savings are pure gain.
• They produce less heat. This matters in summer, and in enclosed fittings where heat build-up shortens bulb life.

How to choose the right LED bulb

Lumens, not watts

Watts measure power consumption, not brightness. With LEDs you need far fewer watts for the same light output, so the number to look for is lumens (lm) — the actual amount of light the bulb produces.

• ~470 lm = similar brightness to a 40 W incandescent
• ~800 lm = similar brightness to a 60 W incandescent
• ~1100 lm = similar brightness to a 75 W incandescent
• ~1520 lm = similar brightness to a 100 W incandescent

Many LED packaging labels include a "replaces X watts" guide, which is helpful, but lumens are the reliable measure.

Colour temperature (Kelvin)

The Kelvin (K) number on a bulb tells you whether the light looks warm or cool. It has nothing to do with how hot the bulb gets.

• 2700–3000 K — warm white. Slightly yellow-toned, close to old incandescent light. Good for living rooms, bedrooms and anywhere you want a relaxed atmosphere.
• 3500–4000 K — neutral or cool white. Crisper and more neutral. Works well in kitchens, bathrooms and home offices.
• 5000–6500 K — daylight. Bright and bluish-white. Useful for tasks needing high alertness or accurate colour — workshops, studios, some bathrooms.

Most people choose warm white for living spaces and bedrooms, and neutral or cool white for kitchens. Try to keep the same colour temperature throughout a room for a consistent look.

Dimmable LEDs

Not all LEDs work with dimmer switches. If you want to dim a light, look for bulbs explicitly labelled "dimmable". Older leading-edge dimmer switches may not be compatible with LED drivers — you may need to replace the dimmer with a modern trailing-edge or LED-compatible dimmer. The bulb manufacturer often publishes a list of compatible dimmers on their website.

Colour Rendering Index (CRI)

CRI measures how accurately a light source renders colours compared to natural light, on a scale of 0–100. For most home use, a CRI of 80+ is fine. For kitchens (where you're judging food), hobby rooms or anywhere colour accuracy matters, look for 90+ CRI. This is usually stated on the packaging.

Base types and fittings

LED bulbs come in all the common fitting types. Check what you have before buying:

• E27 — large screw (standard lamp holders in many countries)
• E14 — small screw (candelabra, some wall lights)
• B22 — bayonet cap (common in the UK, Australia, India)
• GU10 — twist-and-lock spot (common in kitchens and bathrooms)
• GU5.3 / MR16 — low-voltage spot (often requires a compatible transformer)

Smart bulbs — a brief note

Smart LED bulbs connect via Wi-Fi or a hub and can be controlled by an app, voice assistant or schedule. They are genuinely useful if you want remote control, schedules, or colour-changing features. They cost more upfront than standard LEDs. One quirk: if you turn off a smart bulb using the wall switch, it loses its programmed schedule. For most people, a simple timer or standard LED is more practical and reliable. Smart bulbs work best where the switch is left on and the app or voice is the primary control.

Where to start in your home

You don't need to replace every bulb at once. Prioritise by usage — a bulb on for many hours a day saves far more than one used occasionally.

• Kitchen — often on for many hours; usually has multiple spots that add up quickly.
• Living room — main overhead and lamp lighting used every evening.
• Hallways and landings — on frequently, sometimes all day.
• Home office — if you work from home, the desk light runs all day.
• Bedrooms, bathrooms, utility rooms — used less; replace as old bulbs fail.
• Outdoor and security lights — often left on overnight; LED replacements pay back well here.

Replace a bulb the smart way

1. Turn off the power at the switch before touching the fitting. For ceiling fittings, it's good practice to turn off at the circuit breaker too, especially if the fitting has been running recently and the old bulb is hot.
2. Note the base type. Look at the base of the old bulb — is it a screw, bayonet, or pin type, and what size? Take a photo or bring the old bulb to the shop.
3. Check the fitting's wattage limit. Many fittings (especially enclosed or decorative ones) have a maximum wattage printed inside. LEDs draw far less than incandescents, so a 10 W LED is safe in a fitting marked "max 60 W."
4. Choose the right lumen output and colour temperature for the room — see the guide above. If you are unsure, start with 800 lm and 2700 K, which suits most living spaces.
5. If you have a dimmer, check compatibility before buying. Look up the dimmer model and check the bulb brand's compatibility guide. If the dimmer is old, it may be worth replacing it at the same time.
6. Fit the new bulb and test it before putting back any covers or glass shades. If it flickers or buzzes on a dimmer, the dimmer may need replacing.
7. Keep the old packaging until you're happy the bulb works well in that position. Good quality LEDs carry a warranty of two to five years.

Disposing of old bulbs safely

Different bulb types need different handling:

• Old incandescent bulbs — not recyclable in most countries (the glass is not standard cullet). Wrap them and place in general waste. Do not put them in glass recycling bins.
• Halogen bulbs — same as incandescents: general waste in most countries.
• Compact fluorescent lamps (CFLs) — these contain a small amount of mercury and must not go in general waste. They need to be recycled at a designated point. Most supermarkets, DIY stores (B&Q, Leroy Merlin, Home Depot etc.) and household waste recycling centres accept them. Handle them carefully — if one breaks, ventilate the room for a few minutes.
• LED bulbs at end of life — LEDs contain electronic components. Where WEEE (waste electrical and electronic equipment) recycling exists, recycle them at a local collection point rather than putting them in general waste. Many retailers that sell LEDs also accept old ones for recycling.

Common myths about LEDs

• "LEDs are dim." This was sometimes true of early LEDs. Modern LEDs produce full, bright light from the moment they are switched on. Choose the right lumen output and you will not notice any difference in brightness.
• "LEDs are expensive." The price of LED bulbs has fallen substantially and continues to fall. A basic LED bulb costs very little more than a halogen equivalent in most markets, and the running cost savings mean the total cost over the bulb's life is much lower.
• "The colour is cold and unpleasant." This is a matter of choosing the right Kelvin. Warm-white LEDs (2700 K) look essentially identical to incandescent light. Many people cannot tell the difference once the fitting is in place.
• "LEDs don't work in enclosed fittings." Some lower-quality LEDs can overheat in fully enclosed fittings. Look for bulbs specifically rated or approved for enclosed fittings if yours are sealed. Most quality brands now offer these.

Your LED lighting checklist

• Identify the most-used lights in your home — these give the fastest return.
• Note the base type of your current bulbs before shopping.
• Choose lumens for brightness, not watts.
• Match the Kelvin (colour temperature) to the room — warm for living spaces, neutral for kitchens.
• Check dimmer compatibility before buying dimmable LEDs.
• Do not bin any CFL bulbs — take them to a recycling point.
• Replace remaining bulbs as old ones fail, rather than all at once.