Energy Use of AppliancesEvery appliance uses energy, some better than others and there are many variables that go into an estimate of the energy use of appliances.  For example, how often do you use an appliance each day, each week or month? Are they used all year round? What capacity is your appliance? What rate are you currently paying to your provider and do they have a peak rate, a medium rate or an off peak rate. Do you use this appliance in these various time frames that correspond to these rates?

With so many variables, how does the average consumer figure out what an appliance is going to cost him or her and do they really care. Perhaps it is not even worth the effort to figure out all of this stuff. Bottom line is that  if you are not using it and have it turned off, the appliance is not going to use energy unless it has a keep warm feature such as TV’s and computers. In this case they use less energy, but they are still using energy.

If you want to use less energy, essentially turn it off or use it less and you will use less energy. If you still want to calculate relative uses of appliances, you will need to know the following information:

  • Device power  usage
  • Number of hours per day the appliance is used on average
  • Days used per month
  • Months used per year
  • Electrical rate from your power company

Energy Use of Appliances – Device power  usage

Each appliance model has a different usage rate than similar models. Take a fridge for example. The temperature you have it set at, the number of times you open and close the door and the kinds of things you store in your fridge will make a difference in the power usage. When they rate fridges and give you an annual power estimate, it is always under optimum conditions and probably does not correspond to your personal usage. However i can be used as a general guide. You will need the average power rating for each appliance.
Number of hours per day the appliance is used on average

Some people have the TV running all day long whether they watch it or not, while others only turn it on when they are in the same room. The same thing applies to lights, fans heat or air conditioning. You will need to estimate the number of hours per day that your appliance is actually in use. if it is a TV you need to understand the power usage while it is on and the power usage while it is in sleep mode. Many TV’s now have a sleep timer so that it auto shuts off after a specified time frame to conserve power.
Days used per month

How many days per month do you use your appliance. A dryer for example might be used twice a week or 8 times a month, while a TV is used every day and the oven maybe 5 days a week depending on the family.  Each appliance will have a different estimate and it is important to know what these numbers are to estimate your overall usage for that appliance.
Months used per year

Some people go away for the winter e.g. seniors while others it is just for a few weeks a year.  You will only need to be concerned about this factor if it is significant i.e. you are gone for a month or more and do not use your appliances.

Electrical rate from your power company

The rates we pay for electricity vary all over the map depending on were you live and the time of day. Check your latest electrical bill to see what rate you are currently paying and if there is a time of day rate as well. In the writers case we pay 12 cents per kilowatt during the peak of the day which is from 11 am to 5pm. Off peak is from 7pm until 7am and mid peak rates fill in the gaps for the rest. Our off peak rate is 7 cents per kilowatt.

Some examples for our situation are as follows:

Our oven costs us about $25 per year based on running it at 350 degrees for one hour per day on an average of 15 days per month at a 7 cents per kilowatt. Not too bad, so if I use it less I am not going to make a big difference in my annual electrical bill.

We like to have the lights on at the front of the house during the night for security reasons. Using a 60 watt incandescent light bulb, for 9 hours per day average, 365 days per year at 7 cents per kilowatt for 3 lights will cost us $42  a year. Converting to  CFL or florescent lights will cost me $13 per year which is a significant savings and will more than pay for the more expensive CFL  lights.

And my lap top computer only costs $20 per year if I run it every day for 10 hours per day. Focus on the big things to make a big difference in your power usage, however you can save a lot too if you cut back on all of the small items as well


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