Japan's National Institute of Technology and Evaluation (NITE) said that placing trash or cardboard around outdoor air-conditioner units can cause fires [1].
This safety alert comes as temperatures rise during the current summer heat wave. The risk is significant because common household habits can turn essential cooling equipment into a combustion hazard, potentially leading to equipment rupture or explosions [1, 2].
NITE identified a specific pattern of misuse involving the accumulation of objects such as cardboard and general waste near the external machinery [1]. According to the agency, these items often serve as habitats for insects and small animals [2].
When pests are attracted to the debris, they may enter the internal components of the air-conditioning unit [2]. Once inside, these animals can come into contact with the power board or electrical wiring [1, 2]. Such contact can trigger a short circuit and subsequent ignition [2].
In severe cases, the resulting fire can cause the compressor to rupture, which may lead to an explosion [1, 2]. NITE said the practice of placing cardboard and trash around the units is a primary cause of these risks [1].
Officials said residents should keep the area surrounding their outdoor units clear of all debris to ensure proper airflow, and prevent animal infiltration [1, 2]. This preventative measure reduces the likelihood of electrical failure during periods of high demand when units run continuously to combat the heat [1].
“Placing cardboard and trash around the units is a primary cause of these risks.”
This warning highlights a critical intersection between urban sanitation and electrical safety. As extreme heat becomes more frequent, the increased duty cycle of air conditioners puts more stress on electrical components. When combined with biological contaminants—such as rodents or insects attracted by nearby waste—the probability of mechanical failure increases, transforming a routine appliance into a potential public safety hazard.
