"They call it ‘Dirty Sock' syndrome because that's what it smells like, just like a gym locker," said David Debien, owner of Central City Air in Houston and known throughout the country as an air conditioning guru.
"It started showing up 10 or 12 years ago and it has been a difficult problem to solve. We thought it only occurred in the hot and humid climates of the South, but recently a contractor in Boston reported a case. It's getting worse every year. Ten years ago we had one or two cases a year. Last year we had 20 cases at our business alone."