Demand real equipment and NADCA-standard source removal
The single biggest difference between a quality job and a scam is the equipment. A legitimate cleaning uses source removal: a rotary brush (Rotobrush) physically scrubs debris loose inside each duct while a truck-mounted or high-powered portable vacuum holds the entire system under HEPA-filtered negative pressure, so dislodged dust is captured instead of pushed into your living space.
Ask directly: do you follow NADCA standards, and do you put the whole system under continuous negative pressure? If the answer is a household shop vac and a duster on a stick, that is not duct cleaning — it is theater. NADCA (the National Air Duct Cleaners Association) sets the industry standard for how the work should actually be performed.
Verify the license and ask for before-and-after photos
In Florida, the contractor should hold a verifiable state license you can look up — for example, Tampa Duct Cleaners operates under FL DBPR Certified A/C Contractor license CAC1822636. A company that dodges the licensing question, or works under no license at all, is a hard pass.
Then ask for before-and-after photos taken from inside your own ducts, not stock images. A reputable crew documents the work with a camera so you can see the actual contamination removed. Refusal to show you photos of your system is a red flag — there is nothing to hide on an honest job.
Insist on flat written pricing — and watch for the $49 bait
The classic scam is the $49 or $79 "whole-house special." Once the crew arrives, the price balloons with per-vent fees, "extra" returns, sanitizing add-ons, and pressure to upgrade on the spot. Honest pricing is flat and disclosed up front, in writing, before anyone touches your home.
Tampa Duct Cleaners charges a flat $624 per HVAC system for air duct cleaning ($1,248 for two systems) and a flat $275 for dryer vent cleaning — no surprises on arrival. Hales Comfort Club members save 20%. Anything quoted under $100 by phone, sight unseen, almost always becomes a high-pressure upsell at the door.
Red flags vs. green lights
Walk away from: phone quotes under $100, hard upsells the moment the technician arrives, refusal to show photos or a license, vague answers about NADCA or negative pressure, and a "cleaning" that wraps up in twenty minutes. A real, thorough cleaning of a typical system takes roughly two to four hours.
Green lights: a verifiable license, NADCA-standard source removal with HEPA negative-pressure equipment, before-and-after documentation, flat written pricing, and a real track record. Tampa Duct Cleaners is a division of Hales Air Conditioning, serving Tampa Bay since 1986 — a 40-year HVAC contractor, not a here-today-gone-tomorrow door-hanger crew.