The Ideal Thermostat Settings for a Lancaster Summer

Don't bankrupt yourself trying to hit 68°F in July.

Posted on July 5, 2025 | Location: Lancaster, CA

We've all been there. It's 4:00 PM on a Tuesday in Lancaster, it's 108°F outside, and your thermostat says 78°F even though you set it to 72°F. You keep pushing the button down, but nothing happens. Is your AC broken?

Probably not. You're just fighting physics.

The 20-Degree Rule

Most residential air conditioning systems are designed to lower the indoor temperature about 20 degrees below the outdoor temperature. If it's 105°F outside, achieving 85°F inside is easy. Achieving 70°F is essentially impossible for a standard unit without massive amounts of insulation.

Related: Does maintenance help efficiency? Yes.

Our Recommended Settings

To balance comfort and cost in the Antelope Valley, we recommend:

Pre-Cooling (The Secret Weapon)

If you have Time-of-Use rates with SCE, electricity is most expensive between 4 PM and 9 PM. We recommend "pre-cooling" your home by setting the thermostat to 72°F from 10 AM to 3 PM. Then, when the rates spike at 4 PM, bump the thermostat up to 78°F. Your home acts like a battery, storing the cold air.

If your system can't even hold 78°F, you might need a maintenance tune-up to check your refrigerant levels.

AC Struggling to Keep Up?

Let us check your refrigerant charge and coils. A clean system cools faster.

Book a Tune-Up