Thermostat settings that actually save money in a Texas summer

The Department of Energy's figure is 78 degrees when you are home, and the reason it holds in Texas is that every degree lower adds roughly three percent to cooling cost over a season. A house held at 72 in August pays for it. Ceiling fans let most people sit comfortably at 78 by moving air across skin; turn them off when the room is empty, because a fan cools people, not rooms.

In a mild climate you set the thermostat up to 85 while you are at work and the system catches up in an hour when you get home. In Collin County the attic is 140 degrees at five in the afternoon, the ducts run through it, and the house has been soaking up heat through the roof all day. A system asked to pull a house from 85 to 76 at 5:30 pm on a 103-degree day may run until midnight and never get there. Set the away temperature four or five degrees above the home temperature, and let the schedule start cooling an hour before you arrive.

When the compressor stops, the indoor coil is wet with the moisture it pulled out of the air. Fan on Auto lets that water drain. Fan on On blows air across the wet coil and puts the humidity straight back into the house, which is why homes run with the fan On feel clammy at 76. The exception is a house with a filtration system that needs constant airflow, and that is a conversation with a technician.

If your outdoor unit runs in winter, you have a heat pump, and in heating mode a jump of more than two degrees at the thermostat usually turns on the electric backup strips, which cost three to four times what the heat pump does. Set it and leave it, or use a thermostat that knows it is on a heat pump and ramps gently. The Emergency Heat setting is for when the heat pump has failed, not for cold mornings.

They are worth having for the schedule, the remote control when you forget, and the alerts when the house will not hold temperature, which is how a lot of our customers learn their system is struggling before it fails. Two cautions. Most need a common wire, and some older systems do not have one at the thermostat; a technician can add one. And the learning features sometimes learn bad habits, so set a schedule yourself and turn off the automatic eco settings if the house feels wrong.