We sat down with Martine, the owner of airinspector.com, to talk about clean homes — and to ask what she thought about protecting ductwork during construction. She has spent 26 years on this work: roughly 80% residential, 20% commercial, across thousands of homes.

A note on quotes: every line below in quotation marks is something Martine actually said to us, word for word. The rest is our own narration or cited research — we have not put any words in her mouth.

Why we trust her read

Martine isn't a fringe voice. Her firm, Indoor Environmental Testing, carries years of detailed five-star reviews from homeowners, from physicians who refer their mold- and chemical-sensitivity patients to her, and from restoration professionals. A restoration pro with 15+ years called her team "the best I've worked with… an unparalleled level of dedication & commitment." A Wisconsin builder called her "the state's top building biologist" and credited her with being "instrumental in helping us create healthy standards for new home construction and remodeling projects" [6]. That last part is exactly why we wanted her take.

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New homes are not automatically clean

The people who call her are usually already worried about a house — most often homeowners, in both new and older homes. New construction has its own signature: formaldehyde and VOCs off-gassing from materials. A three-year study found formaldehyde and VOC levels markedly higher in new homes than older ones, persisting well past move-in [1], and an analysis of newly built houses found the same [2].

The reaction doesn't always arrive on schedule:

"Sometimes you feel it immediately, sometimes it takes a while."

Sometimes a long while:

"Had jobs where people react to drywall dust 2–3 years after."

The ducts collect what the build leaves behind

Sawing, sanding, and drywall work put a lot of particulate in the air, and it settles into open ducts and register boots — flex duct especially. A study of new HVAC installations measured the accumulated dust and showed that controlling cleanliness during installation reduced it [3]. That matters because HVAC dust can carry fungal spores into the system [4].

Martine's experience lines up. The mold, she said, mostly isn't in the metal — it's in what falls in:

"Find mold in insulation and debris."

And most builds, in her telling, only get a surface pass at the end — "superficial cleanings." She was blunt about how the trade treats air quality:

"HVAC does not get air quality."

Many crews, she said, "use it as a garbage can."

Higher-end homes aren't exempt

You might assume a bigger budget buys cleaner air. Not necessarily — custom work introduces custom risk. In her experience the higher-end homes can be "more at risk," precisely because they're doing things that haven't been done before. She was candid that real prevention comes down to material selection (low- and zero-VOC products, and gas-phase filtration like carbon or potassium permanganate, not just particle filters) and good ventilation during the build — not budget alone.

On mold, she didn't sugarcoat it:

"Mold can get you sick for two months even for the best mold cleaners."

"Not all mold is created equal — some are bad and some are good."

Whose job is it?

Her read: HVAC contractors aren't the receptive audience here — builders are.

"Your air quality is in their hands."

And the standards haven't caught up. There's no law for it, she said — just classes and building-biology certification, and "only smart good builders" are doing it so far. What moves the needle, in her view, isn't regulation first. It's demand from homeowners. This isn't fringe, either: the EPA's Indoor airPLUS program publishes a technical bulletin specifically on protecting ducts during construction [5]. The guidance exists; the gap is how often it's followed.

We asked whether indoor air is really getting worse than outdoor air. Her answer:

"Oh yeah, except during forest fires."

What this means for what we build

We didn't ask Martine to endorse a product, and she didn't. What she described is a gap: ducts left open through the dirtiest months of a build, a trade that treats air quality as an afterthought, and homeowners who find out too late.

A cover that goes in with the ductwork and comes out at trim-out — keeping dust, paint, and debris out of the system the whole time, with a filter you swap as it fills — is our answer to that gap. See how it works → · For builders →

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Sources

• Interview with Martine, owner of airinspector.com, June 2026. Quoted statements are her own words.

1. Hodgson AT, et al. Variations of formaldehyde and VOC levels during 3 years in new and older homes. PubMed 16507040
2. Indoor Air Quality Analysis of Newly Built Houses. PMC6862697
3. The effect of cleanliness control during installation work on accumulated dust in ducts of new HVAC installations. PubMed 12244749
4. Comparison of methods to evaluate the fungal biomass in HVAC dust. PubMed 27924457
5. U.S. EPA, Indoor airPLUS. Technical Bulletin: Duct Protection During Construction. EPA (PDF)
6. Public Google reviews for Indoor Environmental Testing, Inc. (airinspector.com), Madison, WI. Quoted phrases are reviewers' own words.