Proportional Setpoint Automation Help

Configuration
1

I have a mini split AC connected to HA with smartthings and a separate temp sensor in the same room as the AC unit. I would like to make an automation so that home assistant reads the room temperature every 5 minutes on the remote sensor and adjusts the setpoint on the AC unit as follows – assuming my goal is to keep the room as close to 76°F…

If the room is 78°F (2 degrees too hot), it pushes the AC down by 2 degrees from its current setting.

If the room is 79°F (3 degrees too hot), it pushes the AC down by 3 degrees from its current setting.

If the room is 74°F (2 degrees too cold), it pushes the AC up by 2 degrees.

If the room is 73°F (3 degrees too cold), it pushes the AC up by 3 degrees.

I appreciate any help to get me started. Thanks.

2

So lets say at 12:00 the setpoint is 76 and the room is 78.
The setpoint becomes 74.

At 12:05 the temperature has not yet reached the new setpoint of 74, let say it's 77. So the new setpoint becomes 71.

At 12:10 the temperature has not yet reached the new setpoint of 71, let say it's 75. So the new setpoint becomes 67.

It spirals quickly with time pattern triggers.

3

This will probably do a better job of proportional control (if you tune it right):

4

Why do you assume that setting the goal beyond the limit changes the rate at which it cools or heats?
As you approach the goal, it can reduce the effect possibly and de-rate the effect to reduce overshoot, but when you are 2 or more degrees out, it will just run at full to catch up regardless..

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5

Thanks for the reply.

I could increase the time period and add a limit to prevent the set point from going too high/low.

6

A properly sized AC is normally expected to be able to drop the temperature 1-3°F per hour, so modifying the setpoint every 5 minutes isn't really useful.

If you are experiencing wide swings or uneven temps in different areas of the room, you may be better served adding a fan to increase the mixing of warm and cool air.

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7

Would this work with an AC connected to HA through SmartThings?