A programmable thermostat can automatically adjust the temperature in your home to minimize heating or cooling use when it is not needed. But a recent survey by the U.S. Energy Information Administration finds that few homeowners program their thermostat to meet their cooling needs during the summer.

The Residential Energy Consumption Survey collects data from a nationally representative sample of homes in the United States to determine a number of trends, including the use of appliances, electronics, heating systems, and air conditioning. The most recent survey, conducted from August 2015 to April 2016, collected responses from 5,600 households chosen to represent the approximately 118.2 million primary residences in the nation.

The survey determined that 87 percent of homes use air conditioning, including 65 percent that have a central air conditioning system. Forty-one percent of homes have a programmable thermostat.

Based on the survey responses, the EIA determined that only 12 percent of households in the U.S. actually program the thermostat to meet their cooling needs. Twenty-nine percent do not program the thermostat, and 23 percent have a central air conditioning system that does not use a thermostat.

The Department of Energy says homeowners can save money on air conditioning costs by setting a higher temperature when they are asleep or away from the home. The closer the thermostat is set to outdoor temperatures, the less work the air conditioning has to do. Programmable thermostats can start cooling early to restore a more comfortable temperature before a homeowner wakes up or returns home.

In the EIA survey, 45 percent of homeowners with central air conditioning said they simply set one temperature and leave it there most of the time. Twenty-six percent manually adjust the temperature before going to bed or leaving the home, while 18 percent set up a thermostat program and 11 percent turn the equipment on or off as needed.

Homeowners with individual air conditioning units—including window, wall, and portable air conditioners—were more likely to use the last method, with 45 percent saying they turned the unit on when it was needed and off at other times. Thirty-one percent said they set one temperature, while 18 percent adjust the temperature manually at night or when not in the home. Only 5 percent of homeowners with an individual air conditioner said they used a programmable thermostat with it.

Those with central air conditioning systems maintained a fairly steady temperature range. On average, these homeowners said they kept the temperature at 73 degrees when they were at home, 74 degrees when they were away, and 72 degrees at night.

Those with individual air conditioning units also set an average temperature of 74 degrees when no one was home, but preferred cooler temperatures the rest of the time. These homeowners set an average temperature of 70 degrees at night and 71 degrees when they were at home.

Only 3 percent of homeowners said they have a smart thermostat. This type of temperature control, also known as a learning thermostat, observes household behavior and preferences to adjust household temperature without user input.