Here's a couple of screen grabs to help get a better sense of what the fuel-burning heater is doing.
Apologies for the images being small - they are screen grabs from a cheap Android phone running CanIon.
Here, you can see what a large percent of the car's energy is going to just running the heat. That grab is from a few weeks back, when it was rather cold, and BEFORE I had installed the parking heater.
In this screen grab, you can see the difference in heating temperature between the stock electric heater and the aftermarket fuel-burning heater. In the first part of the chart at a little over 160 degrees F, that's the parking heater running. The drop in the chart straight down is when there was a loss in communications, and a long break in time. The temperature around 140 degrees is running the electric heat. Near the end of the chart, where the temperature is rising again, is after I fired the parking heater back up again.