How to implement temperature curve to heating/cooling

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Hi,

Thanks for the great community. I have been now tinkering with Home Assistant for about 15 months and at that time got almost 31 million rows at separate DW database where I’m moving the state history each night. I could say I have now learnt the basics.

However one thing I cannot figure out fully is using HA as central controller for house heating/cooling. To pinpoint the problem, most of the stuff HA controls is just putting on/off something with for example using generic thermostat. I feel that that is not good enough since most of the devices have some kind of levels how much those are heating of cooling (like low, med, high).

This is what I got so far for heating/cooling.

  1. Geothermal heating pump. Just integrated for monitoring trough cloud service (Nibe uplink). This is adjusted with predefined heating curve. (When outside temperature gets colder the water for floor heating gets hotter). Works well but I’m dreaming of integrating weather forecast for temporary adding or taking off from heating curve to anticipate quick changes in outside temperature since floor heating is reacting slowly. This requires some custom script to update cloud service and is out of scope for this topic.

  2. For cooling I got geothermal cooling convectors and I use IR blaster to turn them on or off. Generic thermostat is monitoring indoor temperature and triggering then the IR blaster. This works fine but I would still like to have some steps here. More the indoor temperature increases over the limit, more fan speed is added.

  3. Got also central ventilation device. This got most potential for adjustments since it is integrated with modbus, it affects directly to incoming air temperature and could level out some variation in indoor temperature. Currently I am using 2 generic thermostats for this. One in cooling mode and one in heating mode. When baseline adjustment is 20 C, cooling is triggering it to 18 C and heating to 22 C. In a perfect solution I could populate some curve table with 0.1 C steps. Specific indoor temperature would result specific amount of heating.

See image below. There is indoor sensor I’m using for adjustments. See min/max for scale. Second image is about ventilation heating. T2 is before heating and T5 is after heating. Those steps on T5 is about 2 C. Time period for both is 72 hours.

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image499×844 38 KB

Any suggestions for this temperature curve idea? It seems that the problem is pretty generic since not all heaters work just on/off but have actually various heating power levels.

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You can implement equations relating a process variable to a set point with templates.

Here’s an example of controlling light brightness based on a lux sensor: Is there a better way to control lighting than using scenes?

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Thanks Tom. :+1: That is actually a good idea. Then I could throw in some elifs in case the curve is not linear.

Edit: Actually in my case this won’t work since Modbus integration got only “write_register” service which can only write input registers. I’m currently using Modbus Switch to bypass this limitation and write values to holding registers.