The short answer: before you hire anyone to clean your air ducts, ask whether they're NADCA-certified, whether they clean the whole system or just the vents, what equipment they use, and whether the price is fixed after they've seen the job. A good company answers all four without squirming. A bad one changes the subject to how much dust they found.
Duct cleaning is one of those trades where the work happens out of sight. You can't easily check what was done after the truck leaves, so the questions you ask before it shows up matter more than usual.
1. Are You NADCA-Certified, and Can I Check?
NADCA is the national certification body for air duct cleaning, and most duct cleaning companies in this region don't carry it. Certification means a trained technician on the job and a set of inspection and cleaning standards the company has agreed to follow.
Don't take a logo on a van as proof. NADCA keeps a public directory, and it takes about two minutes to look a company up. Here's how to verify a duct cleaner is actually NADCA-certified.
2. What Exactly Gets Cleaned?
"Whole house" can mean a lot of things. A proper job covers the supply ducts, the return ducts, the registers and grilles, and the parts of the system the air passes through on the way: the air handler, the blower, and where accessible, the coil and drain pan. Cleaning the supply vents and skipping the returns is like mopping half a kitchen floor.
Ask them to walk you through it room by room. If you want to know what that should sound like, here's what actually happens during a duct cleaning.
3. How Do You Do It?
The industry standard is source removal: putting the duct system under negative pressure with a powerful vacuum so loosened debris gets pulled out of the house instead of into your living room, then agitating the inside of the ducts with brushes or air whips to break things free. A shop vac on the end of a hose through the register is not that.
It's also fair to ask how they'll protect your floors and furniture, and whether they'll show you before-and-after photos from inside the ducts.
4. Is the Price Fixed After You See the Job?
This is the one that saves people the most money. The "whole house for $99" offer is a classic for a reason: it gets someone in the door, and the real number shows up once the work has started. We wrote about the hidden costs of cheap duct cleaning if you want the long version.
A legitimate company will tell you what drives the price, look at your system, and then give you one number that doesn't move. Here's what goes into a fair duct cleaning price.
5. Do I Actually Need This?
A company that's willing to tell you "not yet" is a company worth calling back. If your system was cleaned two years ago and nothing has changed, an honest technician will say so. If you're unsure, this decision guide can help you sort it out before anyone shows up.
A Few More Worth Asking
- Are you insured, and can you send proof?
- How long will the job take? (A typical home runs a few hours, not forty-five minutes.)
- What isn't included, and what would it cost to add it?
- Is there a guarantee if I'm not satisfied?
For Businesses
Facility managers and restaurant owners should add one question: can you document the work for an inspector? Commercial kitchen exhaust cleaning has to meet NFPA 96, and the paperwork matters as much as the cleaning when the fire marshal comes through.
The Bottom Line
These are the questions we'd want you to ask us. Any company doing honest work will be glad you did.
