Summer is upon us, which means in offices across the land the annual battle of the thermostat is about to begin. As the weather gets hotter, suit-clad men crank up the AC until their female colleagues' teeth chatter. Women respond by trying to turn the dial make up or resort to stashing sweaters and blankets under their desks.

It is a long-running problem (and one startups have tried to cash in on), but there's always something new to learn about even the most discussed office phenomenon. A new paper published last week in the journal PLOS One, shows that over air conditioned offices aren't just uncomfortable for women, they actually might be making them dumber.

Too much air conditioning makes women dumber.

The research set up was simple: get 500 student volunteers to take a series of straightforward tests containing word and logic puzzles and math problems in rooms that ranged from a brisk 61 fahrenheit to a sweltering 90 degrees.

If you looked at the students' performance on average it didn't appear temperature made much of a difference, but when the researchers separated the men's and women's scores, a much different picture emerged, at least on the math and verbal parts of the test.

"If temperatures are cold, men are much better than women," economist and study author Agne Kajackaite explained to the New York Times. "So there is this gender gap, but then when temperature increases, the gender gap disappears." Increasing the temperature from 70 to 80 raised women's scores by a hefty 27 percent on the math portion of the test. 

Women's cognitive performance starts to take a hit when the temperature falls below 70, or in other words, at the temperatures many companies keep their offices in the summer. It isn't that women's IQ is affected, of course, it's just harder to persevere through tricky problems when you're uncomfortable, meaning you perform at less than your best.

So how should I set my thermostat?

This is only one study testing the effect of cooler or warmer temperatures over just the short period of time it took the volunteers to complete the test. Kajackaite claims it would be premature to use it as a basis to announce a single temperature that best balances the preferences of men and women at work. (Sorry.)

Nevertheless, these results should be useful ammunition for women in the thermostat wars. But keep in mind it is also true that science proves being too hot really does tend to make people lazy, cranky, and quarrelsome. That includes the men you work with. So making the guys sweat it out isn't a great answer either.

As with many things in life, the solution is probably good old-fashioned compromise (or possibly fancy temperature-controlling tech). But if you're making your female team members shiver with the AC this summer, you should know you're also making them into less effective employees than they could be.