When Oncor raises delivery rates, or when your retail electrical provider hikes your kilowatt-per-hour (kWh) cost after your contract finishes, you have two choices: suffer the $500 monthly bill, or artificially reduce your gross consumption. The most brutal rate spikes occur exactly when your house uses the most electricity—at 4:00 PM in August.
"Pre-Cooling" and Thermal Mass
If your house is rigorously air-sealed and layered with R-49 insulation, it acts like a giant Yeti cooler. This allows you to deploy a financial strategy known as "Pre-Cooling."
- 1 You deliberately set your thermostat to 68°F during the early morning (when electricity is cheap and the compressor barely works hard).
- 2 At 3:00 PM, exactly when rates spike, you let the thermostat float up to 74°F.
- 3 Because the house is an impermeable thermal cooler, it takes 4 to 5 hours to drift up to 74°F. Your AC effectively turns off during the most expensive peak-rate window of the entire day.
You cannot execute this strategy in an under-insulated house. A poorly insulated home will drift from 68°F to 74°F in less than 30 minutes, turning the AC back on precisely when rates are punishingly high.