8. So, according to this information we can conclude that if we switched to energy efficient bulbs… Total Cost… Week: $ .28 Month: $1.13 Year: $13.66 WE SAVE… $30.45 / year 217.24 KwH / year Old School Bulbs (Incandescent) Wattage Lumens Energy Efficient Bulbs Wattage 40 450 9-13 60 800 13-15 75 1100 18-25 100 1600 23-30 150 2600 30-52 Total KwH… Week: 2.01 Month: 8.03 Year: 96.38