Background
U.S. residents use more energy now than we ever have in the past. There are many reasons for this. As more people populate the country, energy needs rise. Technology advances, such as industrial processes, sophisticated machinery and computers also require increased energy. Our everyday lives are filled with electrical appliances that our grandparents never used.Why is our energy bill so high? This activity gives you a chance to work on some real-life math problems. This activity bases its numbers on cost figures from one utility. Energy figures in your area may be different. Your local energy utility can give you figures that show the average expenditure per household in your community.
Do this survey twice: once in the morning before school, and once just before dinner. It will help you determine how much energy you use.
| Appliance Electrical Appliance | Multiply by | Subtotal | Total per day |
| Incandescent Lights: Number of lights on = | 1¢ per hour | ||
| Fluorescent Lights: Number of lights on = | 1¢ per every 4 hours | ||
| Television: Number of sets on = | 4¢ per hour | ||
| Radio: Number of sets on = | 1¢ per hour | ||
| Stereo: Number of sets on = | 2¢ per hour | ||
| Microwave oven: Number of ovens on = | 15¢ per hr | ||
| Computer: Number of units on = | 1¢ per hour | ||
| Vacuum cleaner: Number on = |
9¢ per hour | ||
| Portable heater: Number on = |
15¢ per hr | ||
| Air conditioner: Number on = | 55¢ per hr | ||
|
Total for all subtotal usage |
|||
| Total usage in one day | |||
Add up all the numbers in the subtotal column. This subtotal is the total cost for these appliances in one hour.
Some of these appliances will be on for more than one hour, some less. Based on what you know about your household, write the total number of hours and the total cost in one day for these appliances in the Total per day columns above.
Example 1: If two stereos are on for eight hours a day, you multiply 2 (stereos) x 2 cents per hour x 8 hours = 32 cents per day. Example 2: If you vacuum for 1/2 hour, multiply by 9 cents per hour x .5 hours = 4.5 cents per day.
Periodic Appliances
Some items are not used all the time. They create a cost only when they are used.
| Periodic Appliances Appliance and loads per month |
Multiply by | Total per month |
| Dishwasher: | ||
| Loads = | 10¢ per load | |
| Washing machine: | ||
| Loads = | 5¢ per load | |
| Electric clothes dryer: | ||
| Loads = | 67¢ per load | |
| Gas clothes dryer: | ||
| Loads = | 16¢ per load | |
| Total usage for one month |
These answers give you the total cost per month, based on how much your family uses these appliances.
| Periodic Appliances: Appliance and average use per month | Total per month |
| Gas water heater: | $13.00 |
| Electric water heater: | $45.00 |
| Refrigerator: | $16.00 |
| Extra freezer: | $18.00 |
| Electric heating system: | |
| Small home: | $85.00 |
| Large home: | $250.00 |
| Gas heating system: | |
| Small home: | $28.00 |
| Large home: | $120.00 |
| Total for 1 month: |
Try to figure out your home energy costs for one month. Compare it
to the bill that your parents receive each month. How do they compare?My estimate: ______________
My parents' bill: ____________
Did your estimate come close to the actual cost? If not, why do you think they differ?
Credit: The National Wildlife Federation's Animal Tracks Activity Guide for Educators. Copyright © National Wildlife Federation 1995.