BY JOHN SCOTT LEWINSKI
Thursday, August 27, 2015
Maybe this sounds familiar: It’s a summer evening, and you and your significant other are headed to bed. She sets the temperature at 72, because she says it’ll save money on your electricity bill. But you want it at 67, because it’s more comfortable, and what real difference could a few degrees make?
You argue, but nobody ever wins. It can feel like debating whether Christmas is more awesome than Halloween. You’re talking about personal preference, right?
To some degree, sure. Men and women are built differently, and they have very different ideas about what constitutes a “comfortable” temperature.
You probably notice it at the office. If somebody is complaining that it’s too cold, it’s probably not a guy. And there’s a reason for that.
A study released earlier this month—by researchers at the Maastricht University Medical Center in the Netherlands—found that many modern office buildings follow a “thermal comfort model that was developed in the 1960s.” The temperature is based on the metabolic rate of an average 40-year-old man who weighs 155 pounds.
Women in general have lower resting metabolic rates—they aren’t producing as much body heat when they’re sitting behind a desk as men are. So a temperature that guys think is perfect for the work environment is cold enough to have your female colleagues reaching for their sweaters.
And that’s just at the office. At home, in your bed, when neither one of you wants to be shivering or sweating, finding a happy middle ground becomes more vexing.
Dr. Rachel Salas, MD, a neurologist at Johns Hopkins University who specializes in sleep medicine, cites a National Sleep Foundation study that puts the magic number at 65 degrees.
Why so low? Your body's core temperature is naturally low during deep sleep. It starts to raises towards the end of your sleep cycle, as a sort of signal to your body that it's time to wake up.
By keeping the temperature low, you're helping your body do its job. Too hot and it can interfere with your body’s natural temperature adjustments and create restlessness throughout the night. That’s a recipe for insomnia.
But 65 is just a ballpark number. “Most of us tell patients to try between 65 to 69 degrees,” says Dr. Salas. “Personally, 68 works for me.”
And then there’s the matter of your electricity bill. Will you save money by giving the thermostat a break overnight?
Mike Bieschke is a Controls System Design and Support Specialist for Minvalco, a Midwest-based climate engineering firm. Put simply, his job is to consider a building’s overall size and volume during construction or renovation—from a house to a Walmart—and calculate how much climate control is necessary to keep it livable.
Bieschke says that during the summer, you should keep your A/C within a tighter range. If 68 degrees is your comfort zone, don't go too far above or below that—only a couple of degrees in either direction—even when you'll be asleep or away from the house.
Why? “In a cooling system, the compressors use more energy when they start, compared to when they run,” he says. You’ve seen the lights flicker in some places with the A/C activates. That’s because an A/C compressor kicking in takes a big punch of electricity.
If you force your A/C unit to work toward a sudden change in the morning or when you come home from work, with the initial oomph of getting the freon squeezed, it’s going to take a big chunk of energy. And that means bigger electric bills.
But when winter comes—and it'll be here soon enough—the rules change.
Lowering your thermostat by even a few degrees can save you bucks. You don’t have to get ridiculous—it shouldn’t be cold enough that you’re wearing a down jacket to bed—but if your temperature is set at 70, bringing it down to 67 or 66 at night will definitely cut your heating costs.
The Department of Energy recommends turning down your thermostat between 10 and 15 degrees for 8 hour stretches, which admittedly sounds a little nuts. If you like it at 70, you’re probably not going to want to sleep in a bedroom that's just 55 degrees. But according to the government agency, you can save as much as 1% on your monthly heating bill for each degree you lose. That's reason enough to put on warmer pajamas and tough it out.