A new national survey on optimal room temperatures required for sleeping, which was conducted by Google Consumer Surveys last month and commissioned by heating and cooling company Aire Serv, shows that nearly 40% of American adults prefer to set their thermostats between 66 and 69 degrees Fahrenheit while sleeping.

According to the poll, nearly 30% of those surveyed prefer to sleep with their thermostat set between 62 and 65 degrees Fahrenheit, while 22% favor temperatures between 70 and 73 degrees Fahrenheit, and approximately 9% of people prefer to set their thermostats between 74 and 77 degrees Fahrenheit. The data coincides with a recent study conducted by researchers at the University of California, Los Angeles that indicates under typical conditions, temperature is important for regulating sleep.

“Aside from owning a comfortable mattress, a person’s comfort level with their bedroom temperature is a major determining factor as to how well and long he or she will sleep,” says Steve Truett, president of Aire Serv, in a release. “That’s why Aire Serv stresses the importance of routine air conditioner maintenance. It’s not only important for extending the lifespan of the unit, but it also will prevent the unit from not being be able to effectively regulate room temperature.”

Mark Aloia, PhD, associate professor of medicine for National Jewish Health in Denver, has studied health behavior change for the last 20 years. “The results of the survey demonstrate that most people are aware of the relationship between room temperature and sleep. During sleep, our heart rates slow down and body temperatures drop because our bodies want to be at its coolest while resting,” says Aloia. “This recent study also shows that quality is as important as quantity and we know Americans, in general, are not getting enough sleep. In addition to temperature, other external conditions that will promote better sleep include keeping the bedroom quiet and dark.”