Safety & energy-efficiency in large reptile enclosures

Step 6: Fun with algebra....

To calculate the energy consumption of a device per day, I used this equation:
a (b/1000) x c = d

a = the number of like devices (in my case, either lights or heat cable)
b = the wattage of an individual device
c = number of hours it is on per day
d = this is the answer, equal to the amount of kWh (kilowatt hours) used per day

The old setup (2 60W incandescents):
2 (60/1000) x 12 = 1.44 kWh per day
1.44 x 365 = 525.6 kWh per year

The new setup (2 20W CFL's, 2 15W heat cables)
2 (20/1000) x 12 = 0.48 kWh per day
2 (15/1000) x 18 = 0.54 kWh per day
365 (0.48 + 0.54) = 372.3 kWh per year

My energy savings:
- per day: 0.42 kWh per day
- per year: 153.3 kWh per year

I think that's pretty good.
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