Duct cleaning is the most scam-prone HVAC service category — "$99 whole-home" bait-and-switch, blow-and-go visits that move dust without removing it, fake-mold scares used to upsell thousand-dollar sanitization. The pros worth hiring either hold NADCA certification (the industry standard, requires demonstrating process competence) or do this work in-house with HEPA-filtered negative-pressure rigs — not subbed to a carpet-cleaning shop.
Signals we look at
Each provider earns a fit score for this service from a blend of the signals below. When a signal is missing for a provider, it's not penalized — the absence is just absent, not held against them.
Duct work specialization. Provider lists duct cleaning, sealing, or testing as a distinct service line. The bait operators don't — they list "duct cleaning" only when they bid for it.
Duct testing capability. If a shop can test duct leakage (Duct Blaster, blower door), they have the diagnostic mindset that separates real cleaning from cosmetic spray-and-vacuum.
NADCA membership. National Air Duct Cleaners Association membership is the industry's primary process-quality standard (ACR Standard 2021). Held by a relatively small fraction of duct-cleaning shops — most operators in the residential market are not members.
Aeroseal certification. Aeroseal is a proprietary internal-pressurization duct-sealing system requiring manufacturer training to install. A certified Aeroseal dealer is materially distinct from a "we seal ducts" claim — Aeroseal applications can be measured by before/after leakage and produce verifiable improvement, not just visual cleanup.
Google rating. Duct cleaning generates very polarized reviews — happy customers gush, scammed customers warn. A strong rating floor is the minimum trust threshold for a high-fraud category.
Google review volume. 100+ reviews means a meaningful sample. Below that, a single $99-bait happy customer can spike the average; a 5-review shop with a perfect rating is not enough evidence.
How the star score is calculated
The star score blends two things: the provider's overall quality (our 0–100 Vouched Score — see the general methodology) and how strongly they specialize in this service based on the credentials they publish.
Specialization rests on a mix of editorial assessment and verifiable structured fields — manufacturer authorization, technical certifications, response capability, warranty length, and similar signals. The specific mix varies by intent. We give credit for credentials that are publicly verifiable; we don't infer what isn't published.
Visible ranking puts the "Best for" editorial award holder first within each star tier so the badge and the star bar always agree. Providers without an award sort by overall quality. Correction requests are honored — if we missed a credential you hold, the contact at the bottom of this page is the fastest way to fix it.
For duct cleaning, the full-stack operator who publishes duct cleaning, duct testing, AND duct sealing is the gold standard. Cleaning alone is the low end of the category — often "$99 special" outfits without diagnostic capability. NADCA membership (when published) is the strongest single trust signal for this category, with Aeroseal certification a close second — both require manufacturer / association training and are held by a small fraction of the operators in the residential market.
How we build the page title and heading
The page title and visible heading are generated dynamically from the providers actually rendered on this page, not from a static template. Every intent carries a list of wedge candidates ordered most-specific → most-generic; the first candidate whose evidence is satisfied by at least two providers on this page wins. The wedge surfaces in three places: the <title> tag ("Best [intent] in [City], [State] | [wedge]"), the visible H1 ("Best [intent] Companies in [City], [State]"), and the hero subtitle ("See who provides [wedge in noun form]."). The two-provider floor is a Headline-Content Alignment safeguard — a wedge claim must represent a verified pattern across multiple providers, not a single outlier. When no wedge meets the floor, the candidate list falls through to a generic fallback so the page still has a clean heading.
Threshold to appear on the page
To appear on the duct cleaning page, a provider needs a documented duct-work service line and a minimum intent-relevance bar. Duct cleaning is a low-barrier category — many HVAC shops offer it without specializing, and many specialty "duct cleaning" companies aren't true HVAC pros. Providers who clear the bar split into Top picks (editorial "Best for" awards, multiple verified intent-specific credentials, or strong overall Vouched Score) and a directory row of additional area providers.
How customer reviews factor in
Beyond the structured credentials above, we mine each provider's reviews from Google, Yelp, and BBB for explicit mentions of duct cleaning. This serves two purposes — informing who appears on the page, and surfacing real customer voice on each provider card.
Qualifying-evidence path. When a provider's published credentials are thin but their customer reviews repeatedly name duct cleaning, that real customer voice carries weight too — we'll surface them on the page so visitors can see what their customers actually say about this work.
Per-card customer-voice block. When matching reviews exist for a provider, you'll see up to two quoted snippets directly on their card, with the matching keyword highlighted (e.g. heat pump, no heat, after hours). Long reviews are excerpted to keep the matched keyword visible — cuts always land at sentence or word boundaries, never mid-word.
Strict matching, not topic-adjacent. Reviews must explicitly name duct cleaning or close synonyms (brand names like Mitsubishi / Daikin / Fujitsu count for heat-pump and mini-split installs; "no heat" / "heat exchanger" count for furnace repair; "after-hours" / "no cool" / "same-day" count for emergency). A generic "they did the install" doesn't count for this page — that word appears in every HVAC review.
Source labels. Each snippet shows where it came from. via Google snippets include the reviewer name, star rating, and timestamp because Google exposes that metadata publicly. via Yelp and via BBB snippets are unattributed because those sources don't expose per-review metadata.
Editorial filter. This is a \"Best\" page, not a complaint feed — we curate snippets to ones that genuinely speak to duct cleaning service quality.
How to read each provider card
★ Best for Ductwork & Sealing badge — awarded for distinct duct-work specialization with corroborating sealing or testing capability.
Duct Cleaning score (★★★★★) — how strongly this provider's profile matches duct cleaning / sealing.
Vouched Score sub-line — small "Vouched Score: N/100" under the star bar gives a quick overall-quality cue alongside the intent-specific star score. When two providers tie on stars, this is the second sort key.
"Driven by:" line — a short editorial summary above each card's facts strip listing the 2–3 credentials that most influenced this provider's ranking for the intent in question. Surfaces the evidence behind the score without redundantly restating every credential we look at.
Clickable thumbnail — the provider image links to the same dedicated provider page as the name; both target the full credential profile.
External ratings in the footer (Google, Yelp, and BBB when available) — independent multi-source customer-experience signal. Review counts are rounded to the nearest 5+ so the number reflects "size of sample" rather than implying we have today's exact count.
Intent-relevant review snippets — when matching customer reviews exist, up to 2 quoted snippets appear with the matched keyword highlighted (see "How customer reviews factor in" below).
Inline credential marks (✓) — each ✓ is a deterministic word-boundary match against the provider's published text (not LLM-inferred). When a credential isn't shown, the provider hasn't published it in a machine-readable form — that doesn't mean they lack it; ask when scheduling.
Tier 2 directory row — providers in the "Other" section serve the area but don't yet have an award or multiple verified intent-specific signals. Shown with name + Google rating only; confirm credentials by phone before scheduling.
What we don't verify
This page surfaces what providers publish about themselves. We're explicit about the gaps so you can fact-check the high-stakes items before scheduling:
Active NADCA certification (registry lookup at nadca.com is the verification step) — we accept self-claimed.
Equipment used (HEPA-filtered negative-pressure rig vs portable vacuum) — ask before scheduling and request photos if you want to be sure.
Whether "sanitization" upsells use EPA-registered products — most don't; ask for the product name and registration number.
Before/after particulate or mold testing — the EPA's official guidance is that duct cleaning isn't shown to improve health outcomes in absence of visible contamination. Be skeptical of vendor-provided "results".
Our score is a research starting point, not a substitute for getting written quotes and verifying license status with your state board.
How this connects to the overall Vouched Score
The Vouched Score (0–100) is our composite quality score across every category. The fit score on this page is intent-specific — a provider can have a strong Vouched Score overall but a weaker fit score for Duct Cleaning (e.g. a generalist contractor without a specific service specialization). Both numbers tell you different things.
If a provider believes they were ranked low for Duct Cleaning because we missed a credential they hold (NATE certification, manufacturer authorization, labor warranty, etc.), email vouchedpros@gmail.com with the provider name, city, and a link to the published credential. We accept correction requests.