Buy a fancy 5-year eco-lightbulb for $9.79?

Or pay 70 cents per lightbulb, but replace them every 5 months?

h/t @mrvaudrey

Whichever answer you choose, please justify your reasoning using mathematics.

Buy a fancy 5-year eco-lightbulb for $9.79?

Or pay 70 cents per lightbulb, but replace them every 5 months?

h/t @mrvaudrey

Whichever answer you choose, please justify your reasoning using mathematics.

MCAnd …. CFL bulb uses 24 watts, regular bulb uses 100W

Cost of electricity is $0.13 per kilowatt-hour.

watts/1000 = kilowatts.

kilowatts * hours on = kilowatt-hours

So 100 watt bulb left on for 12 hours per day would be 1.2 kWh which would cost $1.56

hannahi would prefer regular bulbs over the eco bulb because its a dollar cheaper for each 5 years