Calculate natural gas costs.

Natural gas costs are calculated in a way nearly identical to electric power. You have monthly use in hours that you came up with in Step 2. You'll convert that figure into a gas measurement called Btu (or a related one called therms), which measures how much gas the appliance will use over the course of an hour. Finally, find out what rate you are paying per Btu (or therm). Then you'll multiplty that figure by the power company's charge per Btu. To find out the rate that you're paying for each Btu, look at your gas bill or call the gas company.

• For each item on your list which uses natural gas, find out its hourly Btu usage by looking at its serial plate or the EnergyGuide label attached to it.
• Multiply each item's Btu usage by the hourly usage per month that you calculated in Step 2.
• Now multiply the item's Btu usage by the rate you pay per Btu. (If your gas company charges per therm, first divide the Btu by 100,000, and then multiply it by the gas company's rate per therm.) The result is how much you pay to run the appliance each month. You've now done a careful estimation of the energy consumption and costs of a single appliance.

Tips:
Too often people replace an appliance only when it has broken down and cannot be repaired (or the cost of repairing it is too high). This can be a costly mistake. If an old appliance uses a tremendous amount of energy, you may actually save money by discarding it before it breaks down and replacing it with a new, more energy-efficient model.

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