Planning on stringing up zillions of flashing lights on your house to outshine your neighbor this year? Well Commonwealth Edison has a step-by-step guide to help you figure out how much that friendly competition will cost you: 
    
    Tips for calculating added energy costs:
    1. Determine how many bulbs are on your strands of decorative indoor and outdoor lights. For example:  1,000 total bulbs.
    2. Check the wattage per bulb - one watt per bulb is common.  For example:  1 watt.
    3. Multiply watts per bulb by number of bulbs. For example: 1 x 1,000 = 1,000
    4. Convert to kilowatts (kW) - 1,000 watts equals 1 kilowatt.  For example: 1 kW 
    5. Estimate the number of hours in a month the lights are on.  For example: 5 hours per day x 30 days = 150 hours
    6. Multiply the total kilowatts by the total number of hours the lights will be on to get the total kilowatt-hours (kWh).  For example: 1 kW x 150 hours = 150 kWh
     7. Multiply the total kilowatt-hours by the total cost of electricity.
     And voila — there’s your bill. For typical ComEd customers, the total cost of energy supply, transmission and distribution of their electricity will be 8.6 cents per kilowatt-hour through the end of the year.  For example, 150 kWh x .086 = $12.90. 
     So, will you still be putting up as many lights are you planned….or maybe adding a few more?