Compatibility of Minisplits and Smart Thermostats
Recent discussion on Remote Control for MiniSplits got me thinking about whether “smart” T-stats (remote or not) are even compatible with MiniSplit Systems. These systems claim to adjust the HVAC based on whether or not they sense motion (ie occupancy).
1. With a mini-split, isn’t it supposed to be more efficient to let it run 24/7 at the same temp, rather than allowing it to idle, then needing to ramp up at a certain time?
2. At what duration of vacancy does it make sense to let the system idle or to change the setpoint to something less comfortable?
– Previous reading here indicates day/night programming & setback for a mini split may not be efficient. OK.
– If one day setbacks are inefficient, how many days does the place need to be unoccupied for it to be efficient to invoke setbacks? If you are gone for a week, surely you could let the house get to an uncomfortable 85 in the summer; 60 in the winter, and let the system ramp back up shortly before or upon your return? Or is this still inefficient?
3. Even if you don’t invoke setbacks at regular day/night occupancy, does it make sense to allow the HVAC to run while the doors are open? I get that it makes sense to dehumidify, but as someone with a separate dehumidifier that runs on humidity alone, I cringe whenever I see the outside unit for the minisplit ramp up while the doors are open with screens closed to “get some fresh air” (and yes, I have an ERV for fresh air, but try explaining that to a non building science person). I’m tempted to try to get my t-stat connected to my smart home system so that I can write a rule for the HVAC to stay off while the doors are open…but maybe the HVAC running to maintain temp for a few hours is more efficient than running at full ramp up once the doors are closed?
Some definitions for the discussion
1. Lets define “Remote” as the ability to view and revise the temp settings when NOT in the house (ie from a remote location). This is different than merely being able to walk around your house with a wireless controller that may use IR, Redlink or another short range protocol to communicate with a nearby receiver wired to the mini split.
2. Lets define “Smart T-stats” as those with internal ability to automatically adjust the system temperature based on occupancy, or other algorithms, without connection to any system other than the HVAC.
3. Lets define a third category as “Smart Home connectable” as t-stats that can be connected to smart home systems and allow the USER to program the HVAC system operation based on parameter data in the smart home system that goes beyond what a smart t-stat would do (such as if x door is open for more than 5 continuous minutes, turn off conditioned air at y zone).
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