It’s summer. For summer, I have a variable compressor mini-split A/C unit which works great — it can cool the place rather quickly, so we don’t have to live at 35 degrees Celsius in our home.
The mini-split is driven using an extremely cheap infrared ESP device, running a custom component for ESPHome which I wrote. It’s nice to change temperatures and fan speeds, or shut the unit off completely, directly from our Home Assistant dashboards.
One issue remained: the girlfriend and I were routinely arguing about the temperature. If we set the unit to 25 degrees, it’s perfect for me, but it’s too chilly for her. If we set the unit to 26 degrees, I’m sweating, but she’s happy. If the fan of the unit is set to low, it won’t appreciably cool the home (especially if it’s too warm outside). If the fan of the unit is set to high, it’s too noisy to sleep.
What if, instead of letting the A/C’s thermostat control the operation of the A/C, we instead had sub-degree (tenth-of-a-degree) automatic control of the unit? What if we don’t have to fiddle with the thermostat at all? Maybe then we can select a temperature that both of us are happy with — and even reduce the fan noise when the place is at a nice, comfortable temperature already.
That’s exactly what I did – and now we don’t touch the A/C at all. Read on to the article to find out how I did it, and to get the code.