Question

When comparison shopping for a refrigerator, you compare two almost identical options, just varying by power and price:

Cost Power Rating SuperCool Fridge $650 780 W
Ice Cold Fridge $700 675 W
On average the cost of electricity is 13.4¢ per kWh (hint: energy can be expressed in kWh instead of J).
Which is the more cost-effective option if you plan on keeping this fridge for at least 5 years?

Answer 1

To determine which fridge is more cost-effective, we need to calculate the total cost over the 5-year period for each option.For SuperCool Fridge:Total energy used = 780 W × 24 hours/day × 365 days/year × 5 years / 1000 = 341,640 kWh

Total cost of electricity = 341,640 kWh × $0.134/kWh = $45,817.76

Total cost of fridge over 5 years = $650 + $45,817.76 = $46,467.76For Ice Cold Fridge:Total energy used = 675 W × 24 hours/day × 365 days/year × 5 years / 1000 = 296,100 kWh

Total cost of electricity = 296,100 kWh × $0.134/kWh = $39,704.40

Total cost of fridge over 5 years = $700 + $39,704.40 = $40,404.40Therefore, the Ice Cold Fridge is the more cost-effective option over 5 years, even though it has a lower power rating.