Adding air duct cleaning to an HVAC company

A service with a reputation problem

Air duct cleaning is one of the few home services that many homeowners associate with scams: robocalls, door hangers promising a whole-house clean at an impossibly low price, and crews who arrive and find 'mold' in every system. That reputation is an obstacle and an opportunity for an established HVAC company. Customers who already trust your technicians want a straight answer about whether their ducts need cleaning at all.

Be careful with how you market it. The National Do Not Call Registry had 259 million active registrations as of September 30, 2025^[4]; unsolicited sales calls to registered numbers are the fastest way to join the category's bad reputation and to break telemarketing rules. Offer the service to existing customers, on inspection evidence, and let the results do the selling.

What EPA actually says

EPA's consumer guidance is blunt: duct cleaning has never been shown to actually prevent health problems^[1]. It does not say duct cleaning is useless. It lists situations where cleaning should be considered: substantial visible mold growth inside hard-surface ducts, ducts infested with vermin such as rodents or insects, and ducts clogged with excessive amounts of dust and debris^[1].

The same guidance warns consumers not to hire duct cleaners who make sweeping claims about the health benefits of duct cleaning, and to be wary of cleaners who claim to be certified by EPA, since EPA does not certify, endorse or approve duct cleaning companies^[1]. On chemicals, it notes that no products are currently registered by EPA as biocides for use on fiberglass duct board or fiberglass-lined ducts^[1]. Every claim in your marketing and every technician script should be consistent with that page; assume customers will read it.

The industry standard

The National Air Duct Cleaners Association publishes ACR, The NADCA Standard for Assessment, Cleaning, and Restoration of HVAC Systems. Its 2025 edition covers cleaning methods including source removal, and cleanliness verification methods including the Surface Comparison Test and the NADCA Vacuum Test, and it can be downloaded free of charge^[2]. Build your procedure on it, and tell customers which standard you follow.

• Assess first: inspect and photograph the system, including the air handler, coils, blower and representative supply and return runs.
• Clean the whole system, not just the registers: the standard's approach covers components that move air, not only the visible ducts.
• Use source removal: mechanical agitation with the system under negative pressure, so loosened debris is captured rather than spread.
• Verify: test cleanliness against the standard's methods and photograph the results.
• Restore: repair access openings properly and seal them.

Cleaning, sealing or filtration?

Where the efficiency case really is

Homeowners often ask about duct cleaning because they want lower bills or more even temperatures. Those problems are usually about leaks, insulation and installation quality. ENERGY STAR says nearly half of the energy used in a home goes to heating and cooling, that sealing and insulating ducts can improve heating and cooling efficiency by as much as 20%, and that improper installation can reduce HVAC system efficiency by up to 30%^[3].

Ducted systems are common: two-thirds of US households use central air conditioning or a central heat pump as their main air-conditioning equipment^[5]. That is a large market for duct sealing and airflow work, which an HVAC company is better placed to deliver than a cleaning-only operator. Many HVAC companies find duct sealing a more defensible add-on than cleaning, with cleaning offered when inspection supports it.

Equipment and training

• A negative air machine or truck-mounted vacuum with appropriate filtration to keep the system under negative pressure.
• Agitation tools sized for your common duct types: brushes, air whips and skipper balls.
• An inspection camera to document before and after conditions.
• Access tools and approved materials for sealing access openings.
• Protective equipment for attics, crawl spaces and contaminated systems.
• Training on the NADCA standard for at least two technicians before the first paid job.

Selling it honestly

Make inspection the product, and cleaning one of several possible outcomes. Technicians already inspect systems on maintenance visits; add a short duct check with photos and a clear rule for when to recommend cleaning.

A workable script for the technician: 'I took photos of your return and two supply runs. You can see a light layer of dust, which is normal and does not need cleaning. What I would fix is this leak at the plenum and the uninsulated run in the attic; those are costing you comfort and energy.' And when cleaning is warranted: 'These photos show heavy debris and droppings in the return. EPA lists vermin and heavy debris as reasons to clean ducts. We follow the NADCA standard and will show you before-and-after photos.'

• Never claim duct cleaning prevents illness or cures allergies.
• Never call the work EPA-certified.
• Show photos for every recommendation, and give customers the photos.
• Price the full system clearly; avoid low teaser prices that grow on site.

When you find mold or vermin

These are the findings that justify cleaning, and the ones most open to abuse, so handle them carefully. Photograph what you see, describe it plainly and avoid diagnosing it. A technician can say 'there is dark growth on the inside of this sheet metal return' without declaring it a particular mold or a health hazard. If the customer wants to know what it is, recommend testing by a qualified indoor air professional.

• Find and fix the moisture source first, such as a leaking drain pan, condensation on uninsulated ducts or a disconnected run in a humid crawl space; otherwise the growth returns.
• Replace, rather than clean, contaminated fiberglass duct board or lined ducts where cleaning cannot remove the growth.
• Seal off and clean up rodent entry points with the customer's pest control provider before cleaning, or the ducts will be contaminated again.
• Use any chemical product only as its label allows, and tell the customer what was used and why.

Pricing a full-system job

Price the whole system after inspection, not per vent from a phone call. Per-vent pricing invites the bait-and-switch pattern customers fear, and it ignores the parts of the job that take time: the air handler, coils, blower, trunk lines and access repairs. Build your price from the number of systems, total supply and return runs, access difficulty in attics or crawl spaces, and whether components such as the coil need cleaning. Put the scope, the standard you follow and the verification method on the estimate, and attach the inspection photos.

Example: an HVAC company adds duct services

Example (fictional): Westfield Heating had referred duct cleaning requests to a cleaning-only company until two customers complained about aggressive upselling. The owner trained two technicians on the NADCA standard, bought a negative air machine and a camera, and launched a duct inspection add-on for maintenance agreement members.

In the first season, most inspections led to no cleaning; many led to duct sealing in attics. The cleanings that did happen were after renovations or rodent problems, with before-and-after photos attached to each invoice. Reviews mentioning honesty became the main source of new duct work.

Should you offer it?

• Yes, if you can follow the NADCA standard with proper equipment and trained staff, and your technicians will recommend it only on evidence.
• Yes, especially if you also offer duct sealing and insulation, where the efficiency benefit is better supported.
• No, if the plan depends on high-volume marketing to people who do not need it.
• Consider referring to a NADCA-following specialist if volume is low and you would rather protect your reputation than run marginal jobs.

For other add-on comparisons, see building a standby generator division and adding pressure washing.