Hi all,
So I would like to share my thoughts around heating, because this what was really got me in to openhab in the first place.

So there are several heating options on the market: Water heating, radiators,hvac, air conditioner, heating cables etc.

To control these you would typically set desired temperature and the heating itself will have some kind of regulator inside(maybe just on/ off with an error margin of 1F or so). Second thing we need to know which can only be found out by experiment, is how fast the heating is responding to a set temperature change. We only need it roughly in my opninion, lets say we want to have 20C at 8 in the morning and we know it takes about 30 min from 16C, then we need to switch on 7.30 right. So we assume that the heating grading is 8C per hour.

So we have to options, we either use that value or we adjust our timers by guessing that the temperature is 16C at7.30 and ignore the fact the it is actually 18C and we could have waited another 10min before turning heat on.

So now the intersting part comes which I would like to discuss with you guys.

So what I have done is that I have created a new sitemap which I call admin, and here I have added some items. Here I have created items for each set point temperature for each room and for each mode.

I have then made 4 modes,

in addition have two modes which are not displayed in the gui, windows open, and night mode(will add these as well)

So my rules are not perfect, but I use presence, ifttt and google calender to try to set the correct mode.

So idea is:
When mode is home, living room set temperature is 20C, when I am away its 16C and holidays I lower it to 4C, and soon home I just turn on heat on maximum untill home temperature are reached.

So my question is what should the ideal temperature be for the differnt modes? Is there any scientific suggestions? I have bathrooom, living room, hallway,2 bedrooms, where one bedroom is combine bedroom and office(guest bedroom)

Do we actually save some energy by turning on and off heat while being away? Is it worth the effort?

How has other done their heating?

I will upload my items and rules if that is of interest.

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Some smart thermostats use current or forecast external temperatures as input to their “time-to-temperature” algorithms, but must also learn and tune over time their estimations for time to temperature, because there is a long list of data that would be required for a more accurate estimation – external surface area, R value of insulation, building materials used, elevation, etc. You could probably gather sufficient inputs in openHAB to do the same estimation calculation that smart thermostats do and adjust over time as your code observes the time difference between calling for heat and reaching the target setpoint. Or, you could let the smart thermostat do that work.

If you are in North America, the ecobee3 thermostat is an excellent choice because it supports wireless sensors placed throughout the house that measure temperature and occupancy, so your thermostat only calls for heat for rooms that are occupied and the average of occupied rooms’ temperatures is below the target setpoint. The thermostat does time-to-temperature estimation over time and knows the local weather forecast, so you can have all of the logic and the inputs to drive in one simple consumer product. And you can watch it all from openHAB, too!

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Here are my set items for reference

Number Heating_LivingRoom_Setpoint (Temperature, Group_LivingRoom)
Number Heating_BedRoom_Setpoint 	(Temperature, Group_BedRoom)
Number Heating_MasterBedRoom_Setpoint 	(Temperature, Group_MasterBedRoom)
Number Heating_BathRoom_Setpoint 	(Temperature, Group_BathRoom)

Number Heating_LivingRoom_Setpoint_Night (Temperature, Group_LivingRoom)
Number Heating_BedRoom_Setpoint_Night 	(Temperature, Group_BedRoom)
Number Heating_MasterBedRoom_Setpoint_Night 	(Temperature, Group_MasterBedRoom)
Number Heating_BathRoom_Setpoint_Night 	(Temperature, Group_BathRoom)

Number Heating_LivingRoom_Setpoint_Day (Temperature, Group_LivingRoom)
Number Heating_BedRoom_Setpoint_Day 	(Temperature, Group_BedRoom)
Number Heating_MasterBedRoom_Setpoint_Day 	(Temperature, Group_MasterBedRoom)
Number Heating_BathRoom_Setpoint_Day 	(Temperature, Group_BathRoom)

Number Heating_LivingRoom_Setpoint_Away (Temperature, Group_LivingRoom)
Number Heating_BedRoom_Setpoint_Away 	(Temperature, Group_BedRoom)
Number Heating_MasterBedRoom_Setpoint_Away 	(Temperature, Group_MasterBedRoom)
Number Heating_BathRoom_Setpoint_Away 	(Temperature, Group_BathRoom)