Air conditioning units will be working overtime during the triple-digit temperatures this week. Credit: Bonnie Arbittier / San Antonio Report

Triple-digit temperatures bring with them all manner of unpleasantness, including, for most people, higher energy bills.

That’s because air conditioning is not designed to cool homes beyond what some call the “20-degree differential,” or about 20 degrees cooler than the outside temperature.

When air conditioners are tasked to close a larger gap — say from 101 degrees outside to 76 degrees inside the home — they tend to simply run continuously in an effort to get there, pushing electricity bills up as a side effect. And since air conditioning can account for nearly half of a residential electric bill, according to CPS Energy, that increase can be significant.

CPS Energy spokeswoman Christine Patmon said that after every heat wave, customers call CPS Energy seeking to understand why their bills are higher even though they didn’t change the setting on their thermostats. In 2020, she wrote a blog post about how the the 20-degree differential can affect AC performance and bills — and to remind customers there are ways to mitigate those higher costs.

In her post, she linked to several other blog posts, all from air conditioner companies throughout the U.S., that explain basically the same thing: No, your air conditioner is not broken because it isn’t cooling like it usually does. It simply isn’t designed for such extreme temperatures.

With San Antonio facing several more days — OK, likely an entire summer — of extreme heat, now is a good time to review conservation measures that can reduce your bill:

  • Set your thermostat to between 78 and 80 degrees. Raise it 2 to 3 degrees when you leave the house. “Bumping up the thermostat truly makes a difference,” Patmon said.
  • Use fans to feel cooler. Make sure they’re spinning in the correct direction: In the summer, fans should spin counterclockwise, so air blows down.
  • Change your AC air filter every two weeks during the summer.
  • Close your curtains and blinds in the morning and leave them closed through the hottest part of the day.
  • Install solar screens on windows to reduce sunlight heat.
  • Take advantage of CPS Energy’s My Energy Portal, which shows a customer’s energy use in near real time, and includes a full library of conservation tips.

While these tips will help moderate the effects of extreme temperatures on energy bills, CPS Energy also routinely asks customers to conserve energy to help stabilize the state’s electrical grid.

An energy conservation guide informs customers on power usage during peak demand days.
An energy conservation guide informs customers on power usage on a variety of power scenarios. Credit: Courtesy / CPS Energy

This week, the utility launched a new, color-coded conservation level program. It’s aligned with the City of San Antonio’s “Beat the Heat” education campaign, which highlights the dangers of heat and precautions to stay safe during heat waves, like the one currently oppressing the city.

Under the new program, San Antonio is experiencing a string of “yellow” days, signifying “peak energy demand.” CPS Energy’s social media posts ask residents to conserve power between 2 p.m. and 7 p.m., when demand is highest. According to the color-coded chart, that could mean, in addition to the conservation tips outlined above, not using major appliances or charging an electric vehicle until nighttime.

Most days that aren’t scorching will be “green” days. Orange and red alerts will only be issued when the Electric Reliability Council of Texas, the state’s grid operator, declares that grid reliability is at risk.

CPS Energy is a financial supporter of the San Antonio Report. For a full list of business members, click here.

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San Antonio Report Staff

This article was assembled by various members of the San Antonio Report staff.