The National Institute of Technology and Evaluation (NITE) issued a warning today regarding fire risks associated with improper air conditioner use.

These safety alerts come as Japan prepares for peak summer heat, highlighting how common household mistakes can lead to fatal accidents. Ensuring units are functioning correctly before high temperatures arrive can prevent avoidable tragedies.

According to NITE, air conditioner accidents occurred between 337 [2] and 345 [1] times over a five-year period ending in the 2025 fiscal year. These incidents resulted in eight deaths [2].

One primary concern involves the placement of objects near the outdoor unit. NITE said that placing water-filled plastic bottles, or other flammable materials, near the unit can cause sunlight to concentrate in one spot, leading to ignition.

Electrical hazards also pose a significant threat. The agency said that extending power cords by adding connectors can lead to electrical fires.

Furthermore, NITE said that "reckless DIY" efforts to install or remove units [3] can lead to ruptures or ignition, creating immediate danger for the homeowner.

To mitigate these risks, NITE is calling for residents to conduct test runs of their cooling systems. While the agency issued this specific warning today, it said that April 10 is designated as "Air Conditioner Test Run Day" to encourage early maintenance.

“Air conditioner accidents occurred between 337 and 345 times over a five-year period.”

The warning underscores a recurring public safety issue in Japan where the intersection of extreme summer heat and improper maintenance creates a volatile environment. By highlighting the specific danger of 'reckless DIY' and the magnifying effect of plastic bottles, NITE is attempting to shift consumer behavior from makeshift home repairs toward professional servicing to reduce the annual spike in residential fires.