Pick the right cap fitting, brightness and colour temperature so your new LED bulb actually fits and works properly.
LED-01Switch off and let the old bulb coolTurn the light off at the wall switch before you touch the bulb. If it's been on, give it a couple of minutes to cool, especially halogen bulbs, which get very hot. You don't need to turn anything off at the consumer unit for a simple bulb change.
LED-02Check the old bulb's cap fittingLook at the base of the bulb you're replacing. Common UK fittings are bayonet (B22, the standard push-and-twist cap) and Edison screw (E27, the standard screw-in cap), plus smaller versions (B15, E14) for lamps, and GU10 for kitchen or bathroom spotlights. The new bulb must match this exactly, or it won't fit the holder.
LED-03Match brightness by lumens, not wattsLEDs use far fewer watts than old bulbs for the same brightness, so watts alone won't help you compare. Check the lumens (lm) figure on the old bulb's packaging or on the bulb itself if it's printed there. As a rough guide, a 40W old-style bulb is about 400-470lm, a 60W bulb is about 700-800lm, and a 100W bulb is about 1500-1600lm.
LED-04Choose a colour temperature to suit the roomThis is measured in Kelvin (K) and shown on the box. Warm white (2700-3000K) suits living rooms and bedrooms and looks like traditional bulbs. Cool white or daylight (4000-6500K) suits kitchens, bathrooms and workspaces where you want a brighter, whiter light. Mixing warm and cool bulbs in the same room looks odd, so keep it consistent.
LED-05Check if you need a dimmable bulbIf the light is controlled by a dimmer switch, you must buy an LED marked "dimmable" on the packaging. Fitting a non-dimmable LED on a dimmer circuit can cause flickering, buzzing, or the bulb failing early. If you're not sure whether the switch is a dimmer, check for a rotary knob, slider, or touch-dim pad instead of a simple on/off flick.
1 each · Dimmable LED bulb (E27 or B22, warm white)
LED-06Buy the bulb and fit itWith the fitting, lumens, colour temperature and dimmable status all matched, fit the new bulb: push and twist gently to lock for bayonet, screw clockwise until snug (don't overtighten) for Edison screw, or push and turn for GU10 spotlights. Handle LED bulbs by the base or plastic body, not the glass or heatsink fins, to avoid marks or damage.
1 each · LED bulb (bayonet B22, 806lm, warm white)
LED-07Test the bulb and check the fittingSwitch the light on and check it comes on properly, with no flickering, buzzing, or delay. If it flickers and you're sure it's dimmable-rated, the dimmer switch itself may be an older type that isn't LED-compatible and may need replacing separately. If the fitting feels loose, hot to the touch, or scorched, stop and get an electrician to check it rather than continuing.
LED-08Dispose of the old bulb properlyDon't put old bulbs in general household rubbish. LED and CFL bulbs contain small electronic components, and CFLs also contain a small amount of mercury, so take old bulbs to a recycling point at a large supermarket or your local household waste recycling centre.
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