In the process of getting solar panels, we talked ourselves into a heat pump with a couple of split heating/cooling units (gotta find something for all those nice renewable kilowatts to do). But it turns out that Mitsubishi designers are either not very smart or really, really want to sell upgrades.
In particular: there’s a button you can push to change from your current setting to a pre-stored alternate setting; there’s also a button for setting a timer to turn the unit on or off according to a schedule. But — unlike pretty much every conventional thermostat built since the energy crisis of the 1970s — there is no way to change the thermostat according to a schedule so that it’s, say, cooler at night than during the day. Some web searches suggest that we might be able to get a wifi-enabled add-on that would let us schedule our heating and cooling with an app. From anywhere in the world.
Oh, and all this is operated by a remote control that is not coded to any specific heating/cooling unit. So if you have two units (say, upstairs and downstairs) and it’s possible for a nice strong IR light to bounce off walls and through doors from the vicinity of one unit to the vicinity of the other…
Maybe when I build the IR-proof flaps that keep both units from doing everything in synchrony I’ll just add a controller that captures some of the signals and includes an RTC. (Even though the local rep has warned me that customers who tried to make their heating/cooling units change their thermostats according to a schedule have experienced unwanted Service Calls.)