Hi everyone, I wanted to share my experience setting up Home Assistant for HVAC management in Phoenix Arizona where summer temps regularly hit 115F and attic temps can exceed 160F.
The challenge
Standard thermostat schedules don't work well here because:
- The temperature delta between desired indoor temp (76F) and outdoor (115F) is massive
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- Pre-cooling is essential but timing it wrong wastes energy
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- Electricity rates in AZ have time-of-use pricing with peak from 3-8pm
My setup
I am using a Honeywell T6 Pro with Z-Wave connected to HA. My automations include:
- Pre-cooling trigger - starts cooling to 73F at 1pm before peak pricing kicks in at 3pm
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- Attic temperature sensor (Aqara) - if attic exceeds 140F, fan automation runs the whole-house fan briefly at night
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- Window sensor integration - disables AC if any window is opened
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- Energy dashboard - tracks daily kWh for HVAC specifically using Emporia Vue
Results
After a full summer I saw about 18% reduction in cooling costs compared to the previous year with manual thermostat management. The pre-cooling automation alone probably accounts for most of that savings.
Questions for the community
- Anyone else in a hot climate doing similar automations? What has worked for you?
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- I am considering adding a radiant barrier temperature sensor to optimize whole-house fan timing. Has anyone integrated that kind of monitoring?
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- For those on time-of-use electricity rates, have you built automations around rate schedules?
Happy to share my YAML configs if anyone is interested in the automation details.
- For those on time-of-use electricity rates, have you built automations around rate schedules?