How Long Does Duct Cleaning Take?

Why we will not give you a number of hours

Search this question and you get a confident range, usually three to five hours, presented as though it came from somewhere. We went looking for where.

It is not in the U.S. Environmental Protection Agency’s (EPA) consumer guidance on duct cleaning. It is not in any building standard, licensing rule, federal safety guidance or study in our source base. We checked EPA, the Department of Energy, the Consumer Product Safety Commission, the Centers for Disease Control and Prevention and the National Institute for Occupational Safety and Health, and the standards published by the National Air Duct Cleaners Association (NADCA), ASHRAE, SMACNA and the North American Insulation Manufacturers Association. None of them states a duration. The durations you see published are conventions the industry repeats to itself, not findings Editorial assessment.

We could add our own estimate and nobody would check. But an invented number looks identical to a derived one once it is on the page, and being able to tell the difference is the whole point of this publication. So: no authority has said, one consumer-research organization said something eighteen years ago, and the more useful question is the one underneath.

The one published duration figure, and how old it is

Consumer Reports, in an article dated February 4, 2008, wrote that a quality job should take two technicians using specialized tools “about 8 to 15 hours to complete” Single source. That is the only duration figure from a reputable, non-commercial consumer-research organization that we could find anywhere, and it is a single source.

Two things have to be said about it in the same breath as the number itself.

• It is from 2008. Eighteen years is long enough for tools, crew sizes and typical scopes to have moved. We are not presenting it as a current benchmark, because nobody has republished or re-tested it.
• It describes a “quality job,” not an average one. It is a description of full-scope work by two people, not a survey of what contractors actually spend on site.

The same 2008 article gives an unexpectedly useful cross-check on everything else we publish. It attributed a price of $400 to $1,000 for a typical 2,000-square-foot house to NADCA. Today NADCA publishes $450 to $1,000, and EPA’s identical $450 to $1,000 Single source traces back to at least a January 2021 snapshot of its page — one origin behind both. The headline price range for this service has moved roughly 12 percent in eighteen years, against cumulative inflation far higher than that. That is the signature of a convention being repeated, not a measurement being retaken — the same pattern we document at length in our audit of published cost sources.

The Consumer Reports passage was reproduced and attributed to the magazine in 2017 by reporting on a Montgomery County, Maryland Office of Consumer Protection warning about duct cleaning coupon scams, which is how we were able to confirm the wording independently of our own fetch. Cite the figure to Consumer Reports and to 2008, always.

What the industry’s own bodies say about time

This is where the honest answer to the question actually lives, and no competitor reports it.

NADCA, the industry’s trade association, publishes a page titled “Cost & Time Estimates.” It gives a cost range. It gives no time estimate at all. It says instead that the time required varies with the size of the home, the number of systems, system accessibility and the level of contamination present, notes that the number of technicians affects duration, and defers entirely to the individual contractor, who should discuss those factors with you and offer a general estimate during an initial phone call. No hours. No days. No range.

ACR, The NADCA Standard, 2025 Edition, does not help either, and for an instructive reason: it is written as an outcome specification. It defines what “clean” means and how to verify it, including a vacuum test against a minimum cleanliness level. It says nothing about how long reaching that outcome should take. So “we were here four hours” proves nothing in either direction against the industry’s own standard.

EPA publishes no figure and instead hands the question to you. Its one duration-adjacent instruction, for homeowners dealing with a contractor who charges by the hour, is to request an estimate of the number of hours or days the job will take and to find out whether there will be interruptions in the work. Note the phrase “hours or days.” EPA contemplates that this can be a multi-day job. We would not read a number into that, but it is not the language of a ninety-minute visit.

What actually consumes the time

The stages below are the work itself, in order. None are optional on a full-scope job, and each is a place where hours go. Our step-by-step account of the process covers the mechanics; here the point is the clock.

Add those up for a twenty-vent single-system house and Consumer Reports’ 8 to 15 hours for two people stops looking eccentric. No single step is slow. There are eleven of them and most repeat per run. That is a reason the 2008 figure is worth reporting even at its age: it is at least consistent with the work as the industry’s own standards describe it.

Why one house takes longer than another

NADCA lists the factors that drive price, and four of the five drive time first: the number of systems, the accessibility of the ductwork and components, the type of ductwork, and the level of contamination.

• Vent count. Consumer advertising is dominated by per-vent pricing at $25 to $50 supply and $40 to $75 return Typical range, which only makes sense because labor scales per vent.
• Number of systems. A second system means a second air handler, second plenums, second setup. One trade source prices two systems at $650 to $1,000 and three or more at $1,000 to $1,500 and up Single source — a single-source figure, flagged as such, but it tells you the second system is not a rounding error.
• Access and duct material. A tight crawlspace takes longer than an open basement, and flexible duct with a plastic inner liner damages more easily than rigid metal, which slows careful work. Our fact base contains no published multiplier for either, and we will not invent one.

Why a short quoted duration is a scope warning

NADCA’s consumer guidance is unusually blunt for a trade body. It warns homeowners to be cautious of extremely low-cost whole-house specials, noting they often include only limited portions of the system and may exclude critical components such as the air handler, blower fans, coils, registers, or necessary access openings.

Line that up against the table. Every component NADCA names is a component that takes time. Remove the air handler, blower, coil, register removals and access openings, and what remains is a hose pushed a short way into each vent. That job genuinely can be done in ninety minutes — which is the problem. The duration is honest, and it is honest about a much smaller job than the advertisement implied.

We are not going to force the arithmetic further than it goes. Consumer Reports’ two technicians for 8 to 15 hours, from February 2008, multiplied by the $90 to $150 published hourly rate for this work Typical range, produces a number well above the $450 to $1,000 that EPA and NADCA quote for a full-scope cleaning. Those figures come from different sources, different decades and different purposes — one is a billing rate that appears mainly on unusual or heavily contaminated jobs, the other a quoted job price — and multiplying them together would be a fake calculation. What survives the mismatch is only the direction: no credible source describes this as a ninety-minute service.

The enforcement record shows what happens at the cheap end. Washington State’s attorney general won a $10 million judgment in a case where the advertising omitted that only half of the heating and cooling system was included, and a 2013 Better Business Bureau study in Denver found one firm advertising a $242 “whole house” cleaning whose fine print limited it to five rooms and ten vents. The owner conceded it was not the whole house. Either the job shrinks to fit the price, which is what “blow-and-go” describes, or the price grows on site to fit the job.

What to ask before you book

1. “How many hours, and how many technicians?” Get both. Consumer Reports’ figure was two people, and one technician for six hours and three for two are not the same job. One technician for ninety minutes is a different job again.
2. “Does that include removing and cleaning every register and grille?” Vague answers here are informative.
3. “Does it include opening the air handler and cleaning the blower and coil?” The most commonly excluded component, and the one that most changes the hours.
4. “Will you cut access openings, and is closing and sealing them in the price?” A job with no access work could not have reached most of the system.
5. “Can I have the scope in writing before the crew arrives?” A written scope is the thing you can hold up later. Our full list of questions worth asking before booking goes further.

If the crew is packing up after 90 minutes

1. Do not sign or pay yet. Ask for the walkthrough first. A competent contractor expects it.
2. Ask to see the collected debris. The collection is the deliverable.
3. Go component by component with the written scope in hand: registers off, cabinet opened, blower and coil cleaned, access openings cut and sealed.
4. Look yourself. Pull a register, use a flashlight, look into the plenum. EPA’s position is that a homeowner may ask for proof of what was found and done, which makes this your right rather than a favor.
5. Ask what was not included. Sometimes the honest answer is that the coil was never in the price — in which case the disagreement is about the advertisement, not the workmanship.
6. Get the outcome in writing before the crew leaves: a return visit at no charge, a revised invoice, or a written statement of what was excluded.

If that does not resolve it, the escalation path is your state attorney general’s consumer protection office and the Better Business Bureau — the two routes through which the documented cases in our fact base actually surfaced. Keep the advertisement, the scope, the invoice and any photographs.

Common misconceptions

“Three to five hours is the industry standard.”

It is a widely repeated figure with no source we could trace to a regulator, standards body or study. It may describe many real jobs. It is not a standard, and treating it as one gives it authority it has not earned.

“A state attorney general found that jobs advertised at two to three hours really take five to eight.”

No. We published that ourselves and it was wrong; this page has been rewritten because of it. The statement that a real job takes five to eight hours rather than two to three was made by the general manager of a competing Colorado duct-cleaning company, quoted by CBS Colorado in its November 25, 2013 report on the state’s action against several firms. It appears in no attorney general filing. It is a rival contractor’s estimate given to a reporter, and it carries the commercial interest that implies. Our note on this correction is in the corrections policy.

“A fast crew is an efficient crew.”

Sometimes. Speed and scope are indistinguishable from the outside, which is why the component checklist matters more than the clock. Two technicians working in parallel legitimately finish sooner than one.

“A long job means they found something.”

This cuts the other way as a warning. NADCA names being told without a proper inspection that mold or another dangerous substance is present as a common red flag. A job that expands on site, with a new finding and a same-day price, is the documented upsell pattern.

“If it takes eight hours, my ducts must have been filthy.”

Duration reflects the size and complexity of the system as much as its condition. EPA is clear that a light amount of household dust in ducts is not evidence of a problem, and a large multi-system house takes a long time either way.

Related questions

Do I need to be home for the whole job?

The two moments that matter are the inspection before work starts and the walkthrough after it finishes. They are also the only two moments when a homeowner can verify anything.

Does the duration tell me the price?

Only loosely. Most residential work is quoted per system, per vent or as a flat whole-home price; hourly billing at $90 to $150 per technician appears mainly on unusual or heavily contaminated jobs. Our cost analysis explains why the published ranges disagree far less than they appear to.

Is a two-hour job ever legitimate?

For a small system with few vents and easy access, potentially. The test is not the hours but whether the component list was completed. Ask what was included, then confirm it was done.

Should the duration be in the contract?

The scope should be. Hours are a useful sanity check on the scope, but the enforceable thing is the written list of what is being cleaned. Get that and the duration question largely answers itself.

What to do next

• The full step-by-step process — the thirteen stages, and what to watch for during the visit.
• Questions to ask before booking — phrased so the answers can be verified.
• What it should actually cost — fifteen published sources, three real price origins.
• Whether you need it at all — the question that comes before scheduling anything.