Choosing LED Bulbs: A Plain Guide for Reading Homes

For decades, buying a lightbulb was simple. You picked a 40, 60 or 100 watt bulb, and you knew roughly how bright it would be. Now the shelves are full of LED bulbs with labels like "806lm", "2700K" and "GU10". Many of our customers around Tilehurst and Reading tell us they find it confusing. This guide explains what those labels mean.

Why watts don't tell you brightness any more

A watt measures how much electricity a bulb uses, not how much light it gives. Old incandescent bulbs wasted most of their electricity as heat, so a brighter bulb always needed more watts. That's why we all learned to read watts as brightness.

LED bulbs give the same light for a fraction of the power. A modern LED that matches your old 60 watt bulb might use only 8 or 9 watts. So the watt number on an LED box no longer tells you how bright the bulb is.

Lumens: the new way to measure brightness

Brightness is now measured in lumens, often shortened to "lm" on the packet. More lumens means more light. Use this rough guide to match your old bulbs:

• Old 25 watt bulb: about 250 lumens
• Old 40 watt bulb: about 470 lumens
• Old 60 watt bulb: about 800 lumens
• Old 100 watt bulb: about 1,500 lumens

Many packets also say "equivalent to 60W" somewhere on the front. That's a helpful shortcut when you're in the shop.

Colour: what the Kelvin number means

Old bulbs all gave the same warm, slightly yellow glow. LED bulbs come in a range of colours, from warm yellow to crisp blue-white. The colour is shown as a number followed by a K, which stands for Kelvin. The lower the number, the warmer and cosier the light. The higher the number, the whiter and cooler it looks.

• 2700K (warm white): closest to your old bulbs. Ideal for living rooms and bedrooms.
• 3000K (soft white): still warm, but a little crisper. Good for hallways and dining rooms.
• 4000K (cool white): bright and neutral. Useful in kitchens, utility rooms and garages.
• 5000K to 6500K (daylight): very white, slightly blue. Good for reading or close work, but it can feel harsh in a sitting room.

If you want your home to feel the way it always has, choose 2700K warm white. Try to use the same colour throughout a room, because mixing them looks odd.

Bulb fittings: making sure it fits

The fitting is the part that goes into the light. Check your old bulb before you go shopping, or take it with you.

• B22 (bayonet): the classic push-and-twist fitting with two small pins. Most common in older British homes.
• E27 (large screw): a screw-in fitting, often found in lamps and newer light fittings.
• E14 (small screw): a thinner screw fitting, often used in chandeliers and small lamps.
• GU10: a small spotlight with two stubby pins. You push it in and twist it. These are common in kitchen and bathroom ceilings.

A word on dimmer switches

Not every LED bulb works with a dimmer. If your light is on a dimmer, look for "dimmable" on the box. Even then, some older dimmer switches flicker or buzz with LEDs. An LED-compatible dimmer usually fixes that.

When to call an electrician

Changing a bulb is a job you can do yourself. Call an electrician if a new bulb flickers, a fitting feels hot, a light keeps tripping your fuseboard, or you'd like to swap old spotlights for modern LED fittings.

If you're in Reading, Tilehurst or the surrounding villages and you'd like a hand, get in touch with Beckley Electrical. We're always happy to talk you through the options with no pressure.