Extra Credit $2(10$ points$)$ Should we use more efficient light bulbs? Determine annual energy savings, dollar savings, and pay back period of changing your incandescent lightbulbs to more efficient types. Lightbulb type Incandescent CFL LED Price$/$bulb $$1\mathrm{.}59$ $$3\mathrm{.}69$ $$17\mathrm{.}97$ Life of bulb $($year$)0\mathrm{.}97\mathrm{.}322\mathrm{.}8$ Based on $3$ hours$/$day Price difference $-$ Energy Savings $---$ Bulb Watts $($W$)601412\mathrm{.}5$ Annual Energy Consumption in kWh $(($W$/1000)$ x $3$ x $365)$ Annual energy savings of the more efficient models $($energy consumption difference$)-$ Life time energy savings $($life of bulb x annual energy savings$)-$ Monetary Savings $---$ Annual monetary savings on energy $($energy savings x price of electricity$)-$ Price of electricity $=$ $$0\mathrm{.}11/$kWh Lifetime monetary savings $-$ Pay Back Period and Total Monetary Benefit $---$ Pay Back Period $($price difference$/$annual monetary savings$)-$ Total monetary benefit for changing lightbulb $($lifetime monetary savings $-$ price difference$)-$ Count all the lightbulbs in your house # of bulbs Determine your annual monetary savings you get by using all CFL and LED bulbs as opposed to the incandescent bulbs $-$ Assume all bulbs are the same Watt equivalent as this spreadsheet Which light bulbs would you choose and why?