• Hidden pipe vibrations may raise stress levels in old buildings
• Experiments link inaudible frequencies to mood changes without perception

A new scientific study suggests that the eerie or “creepy” feelings some people experience inside old buildings may not be linked to ghosts or paranormal activity, but rather to low-frequency sounds produced by pipes, ventilation systems, and boilers.

Researchers explain that so-called infrasound—sound waves below the range of human hearing—can still influence mood and physiology even when people are unaware of its presence. These vibrations are often generated by old heating systems or basement piping.

Experiments showed that exposing volunteers to these inaudible waves led to higher stress levels, increased cortisol production, and greater feelings of discomfort and irritation, even though participants could not detect any sound.

Scientists say these effects may not directly convince someone that a place is “haunted,” but they could create a vague sense of unease, especially among individuals already inclined to believe in paranormal phenomena.

One researcher noted that physical discomfort in such environments could easily be interpreted as supernatural presence by believers, while others may simply perceive it as an unpleasant feeling in an old building.

In a previous experiment conducted in a site presented as “haunted,” results were inconclusive, prompting further testing with 36 volunteers who listened to calm or eerie music, sometimes combined with hidden infrasound.

Findings showed that participants did not notice the presence of these frequencies, yet reported higher stress, irritation, and sadness when they were active, along with measurable physiological changes.

Researchers stress that these results do not explain all claims associated with “haunted” places, but may account for part of the unexplained sensations reported in old environments.

Other experts, however, argue that the impact of infrasound remains debated, and that there is no solid evidence linking it to phenomena such as object movement or visual hallucinations, calling for further research to better understand its effects on humans.