Thermostat logic

[cncjerry]

Silly me, I want to build my own thermostat.  I have the code working with an Arduino Nano 33 IOT and  amazon Alexa.  Question is the control logic.

I have some ideas but was wondering if there is a best practice for furnace control.  We dont have/need A/C here jn San Francisco.

1)  I have temp sensors throughout the house including outdoor temp and humidity
2) only have a single heating zone but priority will go to the bedrooms at night and living during the day.
3)  greater the outside temp / inside delta, the higher the run past the setpoint I would think.
4) I'm basically trying to figure out how tight a loop I should use around the setpoint.  At night I want the loop really loose, for instance.
5) i guess time should also be a factor meaning even if the temperature steps outside the loop, I shouldn't kick it on for a while, but once this happens, the run-over should be greater.

I don't now the correct terms, maybe reading a process control book or two would help.  But for an investment of about $40 plus a couple of remote sensors, I figure I can have something functional.  I'm using DHT22 based sensors and they seem to work well. 

Anyway, that's the basics of this project. I also have a garage door opener roughed out that with a relay block can control the low voltage lights and fountains.   The garage door is closed loop as I am using the limit switches and optical interrupters.

By the way, I'm not trying to save money, just playing around and thought k can add a lot of function cheaply.  But I started thinking about the furnace and thought it takes more code than just: less than setpoint, turn it on;  greater than setpoint turn it off.

Thanks.

Jerry