One in eight U.S. homes uses a programmed thermostat with a central air conditioning unit

Programmable thermostats are designed to help manage energy use, but most of the U.S. households with these controls do not choose to program their thermostats. Based on information collected through EIA’s Residential Energy Consumption Survey (RECS) for 2015, only 12% of the nation’s 118 million households had a central air-conditioning unit that is actually controlled using the programmed thermostat. About one in three households using central air conditioning do not have a programmable thermostat. But even for those households that use central air conditioning and have a programmable thermostat, more than two-thirds of those households control temperatures without actually programming the thermostat.

Programmable thermostats were certified as an ENERGY STAR product beginning in 1995. However, just the presence of a programmable thermostat does not save energy without the appropriate programming. Programmable thermostats were thus removed from the program in 2009 given concerns about realized energy savings. ENERGY STAR still maintains guidelines for the proper use of programmable thermostats.

In EIA’s 2015 RECS, respondents were asked how they set indoor temperatures during the summer. Almost half (45%) of households using central air-conditioning units said they set the thermostat at one temperature and left it there most of the time. The second most common approach was to manually adjust the temperature at night or when no one was at home (26%). Using a programmable thermostat to automatically adjust indoor temperatures was the third most common approach (18%), and it was more common than manually turning equipment on or off as needed (11%).

For households using individual window, wall, or portable air conditioners, close to half (45%) chose to turn the equipment on or off as needed. Programmable thermostats are relatively less common on individual units, as only 5% of households with that equipment reported using a programmable thermostat.

RECS respondents using central air conditioning or individual units were also asked to provide the typical indoor temperature during the summer when someone was at home, when no one was at home, and at night. Although households with central air conditioning and individual units reported similar temperatures when no one was at home (74 degrees on average), those with individual units kept their homes at cooler temperatures at night and when someone was at home.

Smart thermostats, also known as learning thermostats, observe household behavior and create a temperature-setting profile without the need for user intervention. About 3% of RECS respondents reported having a smart thermostat.

More information on household energy use is available in the 2015 RECS reports, tables, and microdata.

Principal contributors: Chrishelle Lawrence, Maggie Woodward, Chip Berry