Preventing Air Conditioning Odor Complaints During Peak Summer: Standardizing Cleaning and Anti-Mold Treatment for Interior of Air Vent Louvers – HONU Co., Ltd.

HONU Co., Ltd. (Headquarters: Akasaka, Minato-ku, Tokyo; CEO: Kenichi Uchida), a company specializing in smoke-free room conversion, odor elimination, and commercial air conditioning dismantling and cleaning, announces the standardization of interior cleaning and anti-mold treatment for air vent louvers in concealed air conditioning units at hotels and inns, effective from services performed on and after July 15, 2026.

With the upcoming peak summer season, it is increasingly important for accommodation facilities to proactively prevent complaints such as "the air conditioner smells moldy when turned on," "there's an unpleasant odor upon entering the room," or "the odor returns during cooling operation." While dismantling and cleaning the air conditioning unit is essential, HONU has identified the air vent louver and its interior—often overlooked and prone to odor issues—as a critical area requiring attention.

[Air Conditioning in Accommodation Facilities]

Guest rooms in hotels and inns commonly use concealed air conditioning units, with the main unit housed within the ceiling. While these units offer aesthetic advantages, their internal condition is difficult to inspect during routine cleaning, and only a limited number of specialized contractors can perform dismantling and cleaning.

Typically, odor prevention focuses on dismantling and cleaning key internal components such as the heat exchanger, drain pan, filters, and interior of the unit. However, the louver—the final passage through which air is blown into the room—and its interior are frequently excluded from cleaning procedures.

The interior of the louver is particularly susceptible to mold growth, as it is where conditioned air from the heat exchanger meets indoor air. During cooling operation, temperature differences easily cause condensation, creating a humid environment where dust and dirt accumulate—ideal conditions for mold.

If mold and dirt remain inside the louver, odors may still spread into the guest room even after thorough cleaning of the main unit. Therefore, effective odor complaint prevention requires not only dismantling the main unit but also cleaning and treating the interior of the air vent louver.

Why Louver Interiors Are Often Overlooked

The interior of the air vent louver is difficult to access through routine cleaning. While the visible outer surface can be wiped, internal mold, dust, moisture-related dirt, and odor sources are often left untouched.

Additionally, few specialized contractors fully understand the structure of concealed air conditioning units and can comprehensively inspect both the main unit and the air vent area. As a result, the interior of the louver remains untreated in many accommodation facilities.

Through its experience in over 6,000 hotel rooms nationwide, HONU has confirmed cases where odor recurrence could not be fully prevented by cleaning the main unit alone. Therefore, by including the interior of the air vent louver—the final outlet of air—as part of its standard service, HONU delivers more effective odor control.

Standardized Service Components

Effective from services performed on and after July 15, 2026, HONU’s concealed air conditioning dismantling and cleaning service for hotels and inns will standardize the following as an all-in-one solution:

- Dismantling and cleaning of the concealed air conditioning unit (including heat exchanger, drain pan, and blower area) - Cleaning of the air vent louver - Removal of mold, dirt, and odor sources from inside the louver - Anti-mold treatment applied to the interior of the louver - Airflow verification before and after service - Odor control recommendations as needed

This enables comprehensive inspection and cleaning of the entire airflow path—from the main unit to the air vent outlet.

HONU’s Key Principles for Air Conditioning Odor Control

1. Inspect not just the unit, but the air outlet

Odors do not originate solely within the main unit. The entire airflow path—including the heat exchanger, drain pan, blower, ducts, louver, and surrounding areas—must be inspected.

2. The louver interior is prone to mold

The interior of the louver, where conditioned and indoor air mix, creates temperature differences and humidity—ideal for mold growth. Wiping only the outer surface may leave internal mold and dirt, which can become odor sources.

3. Preventive maintenance before peak summer is crucial

During prolonged heatwaves, guest rooms operate air conditioning for extended periods. Odor complaints, once they occur, can negatively impact room sales and online reviews. Preventive maintenance before the busy season is essential.

4. As odor control specialists, view air conditioning and odor as an integrated system

HONU has identified the root causes of odor recurrence through on-site experience in smoke-free conversions, odor elimination, and air conditioning cleaning. Its strength lies in combining equipment cleaning with a strategic focus on odor source elimination.

CEO Statement

While dismantling and cleaning the main air conditioning unit often receives attention in odor control, the interior of the louver—the final outlet of air into the guest room—is frequently left untreated.

The louver interior is a location where conditioned and indoor air intersect, making it prone to condensation and moisture. If mold and dirt remain, even a thoroughly cleaned main unit can become a source of odor recurrence.

As odor control specialists, HONU will standardize comprehensive services that cover the entire airflow path—not just the main unit—to help prevent odor complaints in hotels and inns.

Future Outlook

Based on its track record of over 6,000 hotel room projects nationwide, HONU has provided services including smoke-free conversions, room refreshments, concealed air conditioning cleaning, bathroom refinishing, and odor-elimination and antimicrobial coatings.

Going forward, HONU will continue to focus on overlooked odor sources and cleaning challenges in accommodation facilities, supporting improvements in guest room quality and complaint prevention for hotels and inns.