A 5-watt LED can provide lumens similar to a 40-watt incandescent bulb. Wattages are used to measure the amount of energy needed to produce light. By using a multimeter, watts can be determined by multiplying voltage and current from the appliance. LED lights have shorter watts but brighter light because of their semiconductor, which filters the electrical energy by releasing light. Incandescent and halogen bulbs have higher watts since they require the filament to be heated first before the light is produced.