light bulb savings calculations

These calculations display your estimated savings based on assumptions below

For customized calculations enter your own data in the green fields

Wattage
7 watt
Rated Lifetime
8,000 hours
price
$5.25
average incandescant (INC) light bulb
Wattage
watts
Rated Lifetime
hours
price

cost per kilowatt hour
bulb use per day hours

How your savings are calculated

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

8000 / 750 = 10.6667

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

10.6667 * $0.50 = $5.33 cost of replacing the INC bulb

$5.33 - $5.25 = $0.08 replacement savings

Step 3 determine energy usage over the life of this bulb

25 watts * 8000 hours / 1000 watts per kW = 200 kWh

7 watts * 8000 hours / 1000 watts per kW = 56 kWh

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

200 kWh - 56 kWh = 144 kWh lifetime savings

Step 5 find the lifetime energy cost savings

144 kWh * $0.118 = $16.99

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

$16.99 + $0.08 = $17.08 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 / 8000 lifetime hours = 22.81 % of bulb life used per year

22.81 % * 144 kWh lifetime savings = 32.85 kWh yearly savings

22.81 % * $17.08 lifetime savings = $3.90 yearly savings

Savings calculations are presented as an example of potential savings; actual savings may vary based on use, utility rates and other factors. Calculations are based on national averages and assumptions and may be adjusted for a more accurate estimate of individual savings. While EnergyEarth strives to provide the most accurate information, we cannot guarantee the savings displayed.