Family X's Home Utility Usage

Below are plots of Family X's utility usage over the past few years on a monthly basis. The first is their electrical usage where the average energy used per day is plotted for most months since 2003. For eight months (August 2004 through April 2005), an electric vehicle was not being charged. Every other month includes charging of an electric vehicle. From this we can see that this 1100 sq ft home uses about 10 -12 KWH/day without an electric vehicle. Perhaps a goal might be to reduce the usage to less than 1 KWH/day for each 100 sq ft of living space.



The family's natural gas usage is plotted in a similar manner: the average number of therms per day for each month over the past few years. In August and Sep of 2003 the family was doing a little experiment which was a very expensive failure.



Since they have gas heat, they use more in the winter than in the summer. In the future, we will plot their average monthly gas usage vs. the average local temperatures. The slope of this plot will be an indication of the "efficiency" of this home, in therms per degree. Improvements in insulation, new windows, etc., should change the slope of this line. Changes in the gas consumption that is independent of average outside temperature (like insulating the hot water tank, lowering hot water temperature, etc.) should change the intercept. We'll post these data at a later time. It will be very interesting to compare this plot for other houses.

Below we've plotted water usage as average gallons per day. Since a "gallon" has a more visceral meaning than either "therm" or "KWH", this plot generates more of a reaction. Note that this household never uses less than 100 gallons of water per day. But at least they've reduced that over the past two years.




Please refer to this attachment for a pdf version of these plots.

These plots were all generated using Calc from OpenOffice.org.