Contents of this guide
When cleaning is due
The signal is not the passing of time but what the inspection shows. NADCA, the air systems cleaning association, recommends cleaning when an inspection or the building’s history reveals any of these conditions:
- accumulated particles or performance affected by dirt;
- unacceptable odors or visible dirt discharged into the space;
- mold at condition 2 or 3, or an infestation of birds, rodents or insects;
- smoke or water damage, or fire risk in the components.
The EPA agrees on the essentials for homes: it recommends cleaning if there is substantial visible mold, pests or ducts clogged with dust, and not cleaning routinely. That guide is written for homes and does not cover commercial buildings. The EPA also adds that duct cleaning has never been shown to prevent health problems.
Between cleanings, what is due is inspection. The ASHRAE 180 standard sets these checks:
| Component | What is checked | Frequency |
|---|---|---|
| Exposed ducts | Integrity of insulation and vapor barrier | Annual |
| Internally lined ducts | Water damage or biological contamination, up to the first bend or 20 feet (6.1 m) from a moisture source | Annual |
| Grilles, registers and diffusers | Dirt accumulation; cleaned if needed | Semiannual |
| Drain pan, drain line and coil | Biological growth; cleaned if needed | Annual |
Tasks from the 2012 edition of ASHRAE 180. EPA source: Should You Have the Air Ducts in Your Home Cleaned?
How to check it was done right
- Prior assessment and a written proposal. NADCA’s checklist for hiring cleaning in commercial buildings asks for an assessment before the work, a written proposal and a work plan. See the checklist.
- Inspection before and after. The ACR standard requires inspecting before and after cleaning, and recommends a qualified inspector.
- Containment under negative pressure. While cleaning, the section must be kept under negative pressure relative to occupied spaces, validated with a manometer.
- Source removal. NADCA asks for mechanical source-removal cleaning, with vacuums using HEPA filters of 99.97% efficiency and safety data sheets for any chemicals used.
- Verification before putting the system back in service. Each component must be visibly clean, checked right after cleaning and before the system runs. If in doubt, there is a vacuum test with a limit of 0.75 mg of residue per 100 cm². It measures particles, not microbial contamination.
- Written and visual records. The standard recommends delivering an organized, legible record of all the work.
Requirements from the NADCA ACR standard, 2021 edition and the NADCA general specification guide. NADCA published a 2025 edition; confirm with the contractor which applies.
Restaurant kitchens: a different standard
Kitchen exhaust ducts accumulate grease, and the risk there is fire. The NFPA 96 standard asks that a trained and certified person inspect the whole exhaust system at this frequency, depending on the type of kitchen:
| Type of operation | Inspection |
|---|---|
| Solid fuel | Monthly |
| High volume (24-hour kitchens, charcoal grills, woks) | Quarterly |
| Moderate volume | Semiannual |
| Low volume (churches, camps, seasonal businesses, senior centers) | Annual |
Cleaning is triggered when the inspection finds grease buildup. After cleaning, the standard asks for a label on the hood with the date and the technician, and a written report for the owner.
Table 12.4 of NFPA 96, consulted in a third-party copy with no edition indicated. The applicable edition for each premises should be confirmed with the local authority.
The Climatiza Panamá process
Climatiza Panamá, based in Panama City, publishes the step-by-step of its air duct cleaning (page in Spanish). Its page cites NADCA as a reference for execution and ASHRAE for indoor air quality.
| Step | What it does, according to its page |
|---|---|
| 1. Prior inspection | A camera walkthrough of the system, recording the initial state of sections, grilles and the air handling unit. |
| 2. Work plan | Defines access points, sectorization and schedule, to work without stopping operations. |
| 3. Mechanical cleaning | Brushing the inside of the duct with simultaneous vacuuming and filtration. |
| 4. Grilles and diffusers | Removal, cleaning and reinstallation. |
| 5. Air handling unit | Cleaning of the coil, the drain pan and the drain. |
| 6. Disinfection | A disinfectant product suitable for HVAC ducts. |
| 7. Verification | A second camera inspection at the same points. |
| 8. Report | A report with compared photographs and recommendations. |
The delivery includes a written report with scope, date and the team that worked, photographs and video from before and after at the same points, a record of the sections cleaned and those without access, and a frequency recommendation based on how the building is used. That logic of inspection before and after with records is what NADCA and ASHRAE ask for.
Climatiza also serves kitchens with its kitchen duct and hood cleaning service and has pages by zone, for example Costa del Este, Punta Pacífica and Casco Antiguo.
How long since the ducts in your building or kitchen were inspected?
Climatiza Panamá starts with a camera inspection and delivers a report with compared before and after photographs.
Frequently asked questions
How often are air ducts cleaned?
There is no fixed calendar. NADCA recommends cleaning when inspection justifies it, and ASHRAE 180 sets inspection: annual for ducts and coil, semiannual for grilles. Climatiza says frequency depends on occupancy, the type of activity, filtration and whether there have been condensation problems.
How do I know it is time to clean them?
There are odors, visible dirt on the grilles, mold, pests, water damage or affected performance. A camera inspection confirms it.
How do I know the cleaning was done well?
With inspection before and after, written and visual records, and a check that the components are visibly clean before the service resumes.
Are restaurant kitchen ducts cleaned the same way?
No. Exhaust ducts follow NFPA 96, which sets inspection frequency by cooking volume and cleans when grease has built up.
Does cleaning the ducts improve health?
The EPA says there is no evidence that duct cleaning prevents health problems or that a light layer of dust is a risk. Ducts are cleaned for mold, pests, obstruction or fire risk.
Related articles
- Air conditioning maintenance contract for businesses in Panama: what it should include
- The office air conditioning stopped cooling: what to check in the first hours
Sources
- NADCA, ACR: The NADCA Standard, 2021 edition, when to clean, inspection and verification.
- NADCA, commercial building checklist.
- NADCA, 2021 general specification guide.
- EPA, Should You Have the Air Ducts in Your Home Cleaned?
- ASHRAE, Standard 180, inspection of ducts, grilles and coil.
- NFPA 96, ventilation and fire protection in commercial kitchens.
- Climatiza Panamá, duct cleaning process.
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