How much energy do you use and when?

Most people in the southeast will start to see their consumption of energy at home on the rise as the heating season approaches and the heat pumps kick on daily.  Unlike office buildings that are predominately cooled throughout the year due to people and equipment loads, the single family home is more affected by the temperature outside.  When it’s hot or cold outside it’s hot or cold inside.  We typically spend our daytime hours away from the house during the hottest part of the summer day but we are usually at home during the coldest parts of the winter which is at night.  So, our heating bills tend to be higher versus our cooling bills.

One way to confirm this in a graphic snapshot is to utilize your utility company’s online Energy Dashboard.  In my case, this is Duke Energy.  The attached image is of my past 24 months of all electrical energy consumption in my home.  The blue bars are of each months energy consumption (kwH).  The plotted line with dots are the “Cooling Degree Days (CDD)” and the shaded area is the “Heating Degree Days (HDD).”  CDD and HDD values are units of demand for energy to either heat or cool a building in a specific geographic location.  Cold climates will have high HDD values and hot climates have High CDD values.  Charlotte is a temperate climate, on average, but we still use more heating energy in our homes than cooling.  As the HDD values decrease the CDD values increase and vice-versa, reflecting the change in the seasons.

One clear way to tell if your energy consumption is above or below the locally assumed averages is by noting if the energy consumed (blue bars = kwH) are above or below the plotted CDD and HDD values.  If above, then you have consumed more than the external temperature may suggest you would.  If below, then you have used less than the external temperatures would suggest that you would use for that season’s needs.

A particular time of the year where energy consumption tends to be indifferent to the HDD and CDD values is during the Spring and Fall when the outdoor temparature is comfortable, the time when many of us open our windows.  Many times your home interior can be the same temperature as the outside, say 75 degrees, without mechanical assistance.  So, if your heat pump is not heating and your air conditioner is not cooling at this time of year then where is the energy consumption?  Well, it’s in your water heater, your refrigerator, your oven, your television, your lights, your cell phone charger.  Plug loads (wall outlets) account for a large portion of overall energy consumed during this time of year.

The first goal in reducing your energy load is to measure what you use, THEN, take action.  Without knowing how you use energy throught the seasons leaves you with assumptions that can sometimes be inaccurate.  Setting up a profile with your utility is easy, just basic input of your home type and systems and the dashboard does the rest.

For more information on how to set up your account information with Duke Energy go to the following link:  http://www.duke-energy.com/north-carolina/savings.asp

You can only Manage what you Measure.