You can easily calculate the energy cost of seasonal usage, in this case air conditioning. Whether you use all electric or have a combustion source for heat, such as natural gas or propane, using your power bill is a handy tool.

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You will need to have a twelve month history of your power consumption. Most invoices will have a graph that will allow you to approximate the usage, although you may need to call your utility for the information. You will be determining your baseload consumption and seasonal consumption. Baseload consumption are things that don’t vary with the seasons like lighting, the refrigerator, and other appliances. Seasonal energy use includes heating and cooling. We will focus on cooling here and the energy costs associated with it.

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With twelve months of electricity consumption in front of you, find the three lowest months and add them together. Then divide this amount by three (this will give you an average for the lowest months of the year). Then multiply this amount by 12 for the approximate annual baseload energy usage. You now have your annual baseload figure. *Be careful here as some utilities will show daily usage by month, in which case you will need to multiply this baseload figure by 365 to get the annual figure. You will need to read your bill to determine if you need to do this.

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To determine the seasonal use for your cooling, add the actual kWh (Kilowatt hours) used for all twelve months to arrive an an actual electric usage. Now we just need to subtract our baseload figure from the annual figure to arrive at the seasonal consumption in kWh. Then multiply this kWh by the cost on your power bill to get your dollar cost of seasonal cooling.

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