For those of you just stumbling upon this site, I have demand billing from my wonderful power company. There's a long discussion of this here <link>, but suffice it to say that from noon to 7PM I carefully control the usage of power around the house to reduce the power bill. A single mistake that lasts for 15 minutes during this period could cost me a LOT of money. Enough to buy several little computers to control things around the house.
So, I looked at adding the usages and creating a new graph to show the total use from my two freezers and refrigerator over a period of time, but had a brainstorm along the way. I could simply use HighCharts ability to stack graphs. It worked, and now I have a better understanding of my usage that I want to illustrate for people out there that are considering (or doing) the same kind of thing I do.
First though, a recap of the appliances and what their power usage profile is. Here's my refrigerator graph as an area chart: