How Much Money Do I Save by Recharging My Cell Phone at Work?

Introduction

Recharging your cell phone at work may seem like a way to save money, but the reality is quite different. According to Christopher S. Baird, an Associate Professor of Physics, the savings from charging your cell phone at work instead of at home is negligible.

Annual Energy Consumption

To understand the savings, let’s look at the energy consumption of a typical smartphone. For instance, the iPhone 5 has a battery capacity of $0.00545$ kiloWatt-hours (kWh). If you were to completely drain and recharge this battery every day, the total energy consumed annually would be:

Cost of Electricity

The cost of electricity varies, but according to the US Energy Information Administration, the average residential electricity cost in the United States is approximately $0.12$ per kWh. Thus, if you were to recharge your iPhone 5 every day at home, the annual cost would be:

Maximum Savings

If you were to recharge your iPhone 5 entirely at work, the maximum amount you could save by avoiding that $0.24$ cost at home would be:

Thus, the savings by charging at work would be less than $0.50$ per year.

Conclusion

The amount of money saved by consistently recharging your cell phone at work instead of at home is minimal. Essentially, it is not worth the effort to restrict your charging habits to work for financial reasons. Additionally, it’s important to note that the energy consumed by smartphones is a fraction compared to larger household appliances. For example, a new refrigerator uses about $500$ kWh per year, costing approximately $80$ annually to operate.

Practical Implications

In practical terms, the savings from recharging your phone at work are so small that you should feel free to charge your device wherever it is most convenient for you. Your employer’s electricity costs for providing a well-lit workspace far exceed the negligible cost of charging a cell phone.

In summary, while it may be tempting to consider the potential savings, the reality is that recharging your phone at work yields savings of less than $0.50$ a year, which is effectively negligible.