LED light bulbs consume power and this power is typically measured in watts (W) or in larger installations kilowatts (Kw). Accurate power consumption is a direct measure of the cost to power the bulb. Traditionally 'Wattage' is used to define the total amount of energy that the bulb uses. For incandescent and halogen bulbs this is simply the amount of energy that a bulb would consume. Because the efficiency of an incandescent was fairly standard, the wattage was also used to define the brightness, with LEDs this is no longer a standard for determining brightness as LED efficiency can vary from other light sources and between different LED applications.
LED Watts in LED Light Bulbs
For LEDs, the term 'Watts' is being measured in multiple places, and in some cases used as a marketing term. This is causing confusion. We will try to outline the various ways that the term is being used with LEDs and shed some light on what really matters most.
An LED light bulb typically has several components that consume electricity: the driver or circuitry that converts and conditions the voltage of the socket to the voltage of the LEDs and the LEDs themselves. If you add the consumption of all the components of the light bulb this will result in the actual power consumption of the bulb. This is what is needed to determine the electrical cost to you.
You may also find the use of the term 'Wattage' to be just the wattage of the LED elements, not including the energy consumption of the other electronics of the bulb. This measure is not a complete statement of the electrical cost to run the bulb. In some cases wattage is also used as a generalized power of the LED, for example some 1.2 watt LED elements are being billed as 2 watt LEDs, and if a bulb uses 3 of them they will state that the LED light bulb is a 6 watt LED when its actual consumption may only be 4-5 watts (the 4-5 includes the wattage required of the electronic components of the bulb).
Using LED Watts to Find LED Electrical Cost to Operate
Electricity cost, in terms of $/Kw is used to equate power consumption to your electricity bill. If you add the power consumption of all your bulbs (in Kw) and multiply by your cost per kilowatt hour, you will determine the cost to operate your bulbs. The math follows:
total wattage / 1000 * $/Kw = total cost to operate for an hour
