Understand Your Usage

Electric usage varies from day to day and month to month, depending upon a variety of factors including your daily habits, the weather, and the time of year. An increase in your electric usage could be caused by a variety of factors:

Warm Weather

Electricity bills may be higher during the summer months, due to the increased energy needed to cool your home on hot, muggy days. It's simple math:



For example: How much energy does my air conditioner use?

A medium-sized Air Conditioner = 900 watts
Divide that wattage by 1,000 to get the # of kilowatts = 0.9 kilowatts
Multiply the kilowatts (0.9) by the number of hours used (8) =7.2 kWh (number of kilowatt hours used for one night of cooling)
Multiply the kWh (7.2) by the cost (22.5 cents per kWh*) = $1.62 (cost per night to run your air conditioner)

*The total cost per kWh for customers taking Standard Service generation supply is 22.5 cents
(UI delivery is 14.2 cents and Standard Service supply is 8.3 cents) Your supply rate may vary – check you bill.


  • To estimate the hours used, think about how your appliances operate – does the appliance cycle on and off all day? Is it on steady for 8 to 10 hours?
  • Think about how you use your appliance. For example: using an air conditioner while sleeping = 8 hours, times 3 nights a month = 24 hours of use in a month.
  • Look at your bill to understand your billing cycle – it may run mid-June to mid-July, for example, so what you call your July bill may be half June!
  • Look at your bill to find the cost of your delivery charges (page 2) and your electricity supply (page 3).

Now you have an idea of the impact of hot weather and cool comfort on your bill!




Access our FREE tools to help you better understand your electricity use.

  • Our Energy Analyzer tool gives you targeted energy efficiency information, advice and support to help you achieve savings
  • Review our free and low-cost Energy Savings Tips
  • Visit our Smart Energy section to view our menu of energy efficiency programs


Malfunctioning Appliances

A sudden increase in energy usage may indicate a problem with an appliance, heating or cooling system, or water heater. A spike can also be caused by a period of very hot, muggy weather in the summer. Don't forget that since billing cycles are about a month long, sometimes it can be a few weeks before the effect of a heat wave will be seen on your bill.