Choosing lamps and light bulbs

Start with the place and the task

Choose the spot before the lamp. Will it light a reading chair, a work surface or the room as a whole? Measure the space available for the base and shade, and note the height you want. For a plug-in lamp, consider the position of the socket and where the cable would run. Keep these notes beside you when comparing models.

Separate light output, colour and power

Lumens (lm) describe how much light a bulb produces. Kelvin (K) describes its warm or cool colour appearance. Watts (W) measure power input.

Make a separate note of each value when comparing bulbs. If you like your current light, its specifications can be a useful starting point.

Check the lamp and bulb together

Look up the exact lamp model in the manufacturer's instructions. Check the required fitting, such as E27 or E14, the permitted bulb dimensions and shape, and the maximum rating. Compare that rating with the bulb's actual wattage.

Also check the intended room and use, whether a bulb is included and, if you want dimming, compatibility with your particular dimmer. A dimmable bulb still needs a compatible dimmer. When information is missing, confirm it before ordering.

Your checklist before buying

• Write down the task, position and available space.
• Compare lumens, Kelvin and watts separately.
• Match the fitting, shape, dimensions and permitted rating.
• Confirm intended use, included parts and any dimmer compatibility.

Sources in English: US Department of Energy, Understanding lumens and Light bulb buying advice; Philips Hue, LED dimming compatibility.