Spooky feelings in old houses may be caused by boiler sounds, study suggests

The findings suggest that even when people are unaware of the presence of infrasound, the inaudible waves may still affect them. Illustration: BrilliantEye/Getty Images/iStockphoto

For believers in the paranormal, unsettling sensations brought on by old buildings can be a sinister hint of loitering spirits. But new research points to a more mundane explanation: inaudible sounds from aged pipes and boilers.

Scientists investigated the impact of infrasound on a group of volunteers and found that even though it was beyond the range of human hearing, people were more irritable and levels of cortisol, the stress hormone, rose when the sound was switched on.