I want to write a script to change HVAC mode between cooling and heating.
Do I change on time of the year ? (for ex between oct and febr I heat, all other cool ) On what date do I start ?
Or changing by temperature ? On what temp ?
Or does it not matter if it is cooling to lets say 21degrees or heating to 21 degrees ?
How the heck should we know?
This is entirely dependant on the seasonal variability of your local climate and your house insulation properties.
sorry to ask.
thanks
You could do something scientific and use the mean temperature of the last week or something.
Set up the sensor and wait for the time of the year when you think it’s time to switch and note down the temperature.
Then next year you use this value for your automation.
It probably won’t be perfect, but at least your taking some steps in the right direction.
Many years in the future you might get a good value of what outside temperature you need to switch it.
Maybe explain more what you’re trying to accomplish. I know I reach a point where I think there will be no more heat, or no more cooling, for the rest of the season. But more often than not, we get an exceptionally cold or warm day, and I end up switching back. I don’t see any way to predict when that magic day will come, or if I might have to revert back for a few days.
One thing I know people hate is when landlords set an arbitrary date to shut off the heat (or cooling) in a building. There are always exceptionally warm or cool days in the Spring and Fall.
The only use I could see for something like this in my climate would be to “lock out” people from using heat on a warm day, or cooling on a cool day. That would have to be tied to the actual outside temperature though, not to the calendar. Maybe other climates are more predictable than mine.
Your country’s weather bureau may offer historical data, for “heating degree days” that can help you identify the heating season for your location.
I have an air conditioning unit in the bedroom and if the room temperature drops below 18 degrees, the air conditioning starts heating. If the room temperature rises above 26 degrees, the air conditioning will cool.
If the room temperature is between 18 and 26 degrees, the air conditioning is turned off.
Exactly what i was going to say, except that i am using 20 and 24, and it works just great!
I think that “general change” can’t be done, or at least it’s not practical neither sensable. Weather is unpredictable… it can be freezing today and darn warm again next week. Beside that, it entirely depends on you: your house, insulation, location, and above all: your feeling. Some people live comfortably at 18 degrees inside, some at as high as 28 (celsius), so it’s entirely up to you when to do this switch.
I think that there’s no need for “general switching”. As two guys above wrote: you make two automations: one for cooling, one for heating. That’s what i have, too. I have input number helpers created and with them i can change desired toggle temps for starting to heat or cool, depending on my feeling etc… but generally i start to heat below 20 and cool above 25-26.
Climates generally have auto mode, where this switching is made automatically inside climate itself, but that would mean that climate must be constantly switched on. I never use this mode.
Perhaps I’ll throw in a quick summary at this point.
I understood Jo’s question to be: “What mechanisms can I employ?”, rather than: “What should my specific settings be?”
So far, the answers are:
I live in a place where temperatures are seldom unbearable (but can be quite uncomfortable).
I’ve been asking myself a similar question. I’ve been recording a temperature difference statistic for more than a year now (specific rooms inside and the outside temperature). So far, I don’t have a clear signal – at least not something I feel I can trust and won’t override. More analysis is needed.
I’ve also been playing with various thermal indices to use a more interpreted form of temperature (better than a “feels like” temperature, I think). As has been said, this is quite a subjective matter. Note that humidity plays a vital role in how you perceive the climate — not only temperature.
I used that at very first when i installed my climates, but not for long - it turned out a bad idea. First, it changes too often from heating to cooling, back to heating, cooling again… too much energy is wasted when climate is converting phases, plus you don’t need up to one degree accurate temperature in the room, floating from, say, 20 to 25 is quite ok.
Second, since climate is always on it consumes way too much energy. Way more than needed.
Here weather is opposite from you: at the winter it can be below zero (celsius) while at the summer right now it’s above 38 (they call it “heat wave”), so we should ask ourselves if Jo’s intention is to use climate “in between” periods (spring, autmn) when you have your central heating system turned off and you just need to adjust room temperature when needed or the intention is to use it 365 days/year. Those are two different situations. The basic question was placed way to general to assume what he actually means to ask.
Personally, I agree. I think the fundamental change between a cooling and heating mode will always be problematic in this way, until humankind figure out a way to have a smooth transition (maybe the AC experts will point out that there’s a way to achieve this).
I was summarising the three points already made, before adding my own thoughts. 
Completely agree. It would be for Jo to clarify. I think there isn’t a single, general answer to the question as it was stated.