Does anyone know if this could be used to "cap" the AC settings ? It could be useful in an airbnb place, where I want to limit the lowest (e.g. 18 degres Celsius) or hottest (e.g. 22 degres Celsius) the guest can set the AC.
Or multiple AC units can be networked and managed over Ethernet: https://www.mitsubishielectric.co.jp/ldm/control/function/
People do start placing hand warmers on the panel if you lock them down too much, but what you asked should be possible in principle.
Edit: Looking through the repo and the article I see nothing blocking you. You certainly won't break anything!
Some AC can go ridiculously low (http://news.bbc.co.uk/2/hi/uk_news/england/3144803.stm). I do not want to change the temperature remotely, I just want to not have the AC used to extremely cold temperature. I am fine to advertise it to weed of people who like it very cold.
Most programmable thermostats in the US do have built-in limits for device protection.
I've never met anyone who sets AC in a home to lower than 68F and that is an absolute extreme. Most central AC systems are designed for ~20 degree temperature differential so on really hot days you'd have trouble getting it that low anyway unless the system is oversized.
Yeah, why set the upper limit to 22 and not like 24-25? It will save you even more power for those that don't sit in your airbnb in a 3 piece business suit...
18C is not uncommon in the UK. They seem to like it colder. Italy is down south so 25C may already be getting cold for them. Then there's the Indians who like it closer to 30C...
Did you just post a link to a 23 year old news article with no sources on an http-only site as supporting evidence that your airbnb unit's AC unit can go dangerously low?
You really think your guests will get frostbite if you don't do them the favor of limiting the AC temperature (with the unintended side-effect of saving you some money)?
Of course any guest is free to write in their review “can’t make temperature lower than 18°!” but the number of people choosing not to book for that reason in any given year is likely 0 or very close to it.
There are a lot of people who don’t “get” thermostats and their intuitive model of ACs is like that of getting a bath to a particular temperature by turning a faucet to full hot or cold to get what they want.
And if these people are out of the room when it reaches the actual temperature they want (and would change it), then the AC is left possibly for hours working full time, burning maximum energy and related wear and tear by trying to hopelessly achieve an unattainable temperature.