This is a common question for any person who wants to try this product. We need some proper authority approval or scientific backing to believe.
In the year 1984, University of Nebraska – Lincoln, United States did a comprehensive testing on different samples of ultrasonic devices in various closed chambers for number of days with live rats and published a comprehensive report.
The report EFFICACY TEST PROTOCOLS FOR EVALUATION OF ULTRASONIC RODENT REPELLENT DEVICES is published in the university official website. Link: http://digitalcommons.unl.edu/vpc11/37/
Stephen A. Schumake
Denver Wildlife Research Center
G. Keith LaVoie
Denver Wildlife Research Center
Kenneth Crane
Denver Wildlife Research Center
The report can be download and printed – PDF format
The report concludes as –
“Both the laboratory and field test protocols were found to be easily applied for the efficacy
evaluations of ultrasonic rodent repellent devices. Repellency effects on existing rodent infestations
were evaluated with six official EPA sample devices. Devices were assessed in wood, brick, and metal
structures ranging in floor space from 6.5 to 197 sq m. In all cases, rodents under test could either
leave the buildings or move to alternate non-ultrasonically treated areas. Separate evaluations were
conducted to assure that adequate food, water, and harborage were available at these alternate locations.
Tabulated data from these efficacy tests can also be used to evaluate ultrasound repellency threshold
levels and potential habituation effects.”
Therefore, we conclude that “Ultrasonic Rat Repellent” works best if it is used in any closed premises, car bonnet area, etc. But, please do not use in Open outdoor areas, you will not get the results as the ultrasonic sound gets diluted in the open air.