It's worse than that. He rambles on, and then immediately shifts the metaphor to a more complicated and less clear one. He should have just stuck with the thermostat: if the temperature inside a house is determined by a thermostat, the outside temperature has no correlation with the inside temperature.
I suspect this is because he's already written several other posts (linked at the bottom) with the thermostat example, so is trying a different example here, in the hope that people might pay more attention this time.