LEDs are more expensive, but their energy consumption is extremely low, and can save you between £4 and £15 a year per bulb, depending on what kind of bulb you’re replacing. LED lighting is measured in lumens. Lumens are a measure of the total amount of visible light from a lamp or light source. The higher the lumen rating, the brighter the lamp, and the lower the lumen rating, the dimmer the lamp. Using lumens lets you choose and buy the amount of light you want. Watts on the other hand, are a measurement of power consumption and energy used.