Step 1 find the number of INC bulbs needed over this bulb's lifetime

35000 / 750 = 46.6667

Step 2 determine the cost of replacement INC bulbs and the difference with this bulb's cost

46.6667 * $0.50 = $23.33 cost of replacing the INC bulb

$23.33 - $16.95 = $6.38 replacement savings

Step 3 determine energy usage over the life of this bulb

40 watts * 35000 hours / 1000 watts per kW = 1400 kWh

8 watts * 35000 hours / 1000 watts per kW = 280 kWh

Step 4 subtract to find the difference in energy usage between the bulbs

1400 kWh - 280 kWh = 1120 kWh lifetime savings

Step 5 find the lifetime energy cost savings

1120 kWh * $0.118 = $132.16

Step 6 combine energy savings with replacement cost savings to find total lifetime savings

$132.16 + $6.38 = $138.54 total lifetime savings

Step 7 find savings per year

5 hours per day * 365 days per year = 1825 hours per year

1825 hours per year / 35000 lifetime hours = 5.21 % of bulb life used per year

5.21 % * 1120 kWh lifetime savings = 58.4 kWh yearly savings

5.21 % * $138.54 lifetime savings = $7.22 yearly savings