Where I’m at, the temps flip-flop day to day, even hour to hour. In the morning it’s 35° outside, and by evening it’s 79°. I gave up keeping up with the temps and shut my unit off for the time being.
My question is why can’t HVAC units be programmed to say that if the outside temp reaches n° and the inside temp reaches m° cold, turn on the heat; conversely, if the outside temp rises to n° and the inside temp reaches m°, then turn on the AC?
My thermostat already knows the outside and inside temp, but I still have to manually switch it back and forth. I want a system that I can just set it and forget it all year round.
You don’t really need complicated control theory for HVAC (at least, on a per-room or house basis) , since the system has such a huge heat capacity and takes a long time to change. Simple set point control with 100% on/off operation and a 2 degree dead zone gets the job done
“Bang-Bang”, the simplest feedback controller in control theory.