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The original was posted on /r/homeassistant by /u/froggtech on 2026-06-22 19:38:52+00:00.
My utility (Consumers Energy, Michigan) switched to summer time-of-use pricing on June 1 — ~24.5¢/kWh weekdays 2–7 PM, ~19.7¢/kWh every other hour. So I built a system to shift my AC load out of that expensive window automatically. The standard advice is "pre-cool then back off the thermostat," but I didn't want to babysit it, and a flat schedule is dumb on days that aren't average. So I made it adaptive to the forecast.
The shape is three beats — pre-cool, coast, restore — plus a comfort layer for my office.
The clever bit: the setpoints scale to the day's forecast high. A helper grabs the OpenWeather forecast high each morning, and the pre-cool depth keys off it:
- ≥90°F → pre-cool to 66
- ≥82°F → 68
- ≥76°F → 70
- below 74°F → skip entirely (house coasts fine on its own)
Then at 2 PM the coast ceiling scales inversely — hot days coast lower (74), mild days higher (78) — because on a brutal day I'd rather the compressor kick back on than cook the office. Measured ~2.2°F/hr pulldown and ~1°F/hr drift, so on a normal day the compressor stays off the whole 2–7 window.
Comfort layer: an Apollo MSR-2 mmWave sensor runs the office fan at 33% only when I'm actually in the room (mmWave, so it doesn't quit when I'm sitting still). The fan buys ~4°F of felt cooling for pennies. A guardrail drops the thermostat to 72 only if the office passes 83°F for 10 min and it's occupied — so an empty office never triggers the expensive override.
Two helpers hold it together: a master-enable boolean (one toggle kills the whole system) and the forecast-high number. Seven automations total.
Honest caveat: I don't have whole-home energy monitoring yet, so I can't show a dollar figure — just the mechanism, which is sound. That's the next build.
Full writeup with all seven automations as copy-paste YAML (genericized):
https://testing12.org/i-taught-my-house-to-dodge-peak-rates-a-home-assistant-peak-shaving-system/
Happy to answer questions on any of it.