After a renovation, clean your ducts only if an inspection shows construction dust inside them. In South Florida the air conditioner runs for much of the year, so dust from a renovation can travel through the system. The better plan is to protect the system during the work and to check it afterward.
Renovation dust finds its way into the ducts
Sanding, cutting drywall, and tearing out tile all put fine dust into the air. Your air conditioning system moves air through return grilles, and it can pull that dust into the return ducts and the indoor unit. NADCA, the trade association for duct cleaners, says HVAC components often collect significant debris and particulate during construction. It lists contamination with construction particulate or debris as a condition that can call for cleaning.
Protect the ducts during the work
The EPA gives clear advice. During construction or renovation work that produces dust, seal off the supply and return registers, and do not run the heating and cooling system until after the dust has been cleaned up. In South Florida, that can be hard in summer, so plan the work with your contractor. Ask how they will contain dust and how long the system will be off.
- Before the work: Ask your contractor to cover supply and return registers with sealed covers.
- During the work: Keep the system off, or ask your contractor how to run it safely.
- After the work: Clean up the dust first, using a HEPA vacuum or the highest-efficiency filter bags you can find, as the EPA suggests.
- Before you turn the system on: Remove the register covers, and put in a new filter.
- After a few days: Check the new filter. If it is already dirty, dust may still be moving through the system.
Lead safety for renovation dust in an older home
If your home was built before 1978, ask first. The EPA says homes built before 1978 are more likely to contain lead-based paint, and it recommends hiring a contractor who is certified and trained in lead-safe work practices. Cleaning ducts afterward is not a substitute for lead-safe work during the renovation. If you are not sure, ask your contractor about their certification before work starts.
When do ducts need cleaning after a renovation?
NADCA recommends that the HVAC components of a construction, retrofit, or remodel project be inspected and verified as clean before the system is allowed to run. You can use the same idea at home. Look first, then decide.
| Situation after the work | What to check |
|---|---|
| Small job, system was off and registers were covered | Filter and a few vents. A camera inspection may be all you need. |
| Heavy dust job, system ran during the work | Return ducts, the indoor unit, and the supply ducts. |
| Visible dust or debris coming out of the vents | A look inside, by camera where the system allows it, then cleaning if debris is confirmed. |
| Water was involved (plumbing or roof work) | Look for moisture stains and wet insulation. The EPA says wet or moldy duct insulation should be replaced. |
| Home with old ducts or unknown materials | Ask the technician to check the system before any cleaning. |
A dusty return grille alone is not a sign of a problem. The EPA says it is normal for return registers to collect dust, and that this does not show heavy contamination inside the ducts.
A camera inspection after a renovation shows the dust level
It shows whether dust is a thin film or heavy build-up. It can also show debris, such as drywall pieces or screws, and damage to the ducts. Our guide on what a duct camera inspection shows lists what the pictures may mean. Wherever your system allows it, we start with a camera look inside, and we show you what we see. If it shows only a light layer, you may not need cleaning. If your ducts do not need cleaning yet, we will tell you.
When cleaning is needed
The EPA says cleaning should open the whole system for cleaning and inspection, use vacuum equipment that exhausts outside or has a HEPA filter, and protect your floors and furniture. We follow an inspect, clean, and inspect again process:
- Inspect. Wherever your system allows it, we start with a camera look inside.
- Remove. We remove construction dust, along with the dust, allergens, pet hair, debris and bacteria that have settled in the ducts.
- HEPA-filtered vacuum. Rotary brushes loosen the buildup, and a HEPA-filtered negative-pressure vacuum keeps the ducts under suction and removes it from your home. Debris is collected through HEPA-filtered equipment, never blown into your living space.
- Whole system. We clean every duct and vent in your home.
- Botanical finish. We finish with a botanical product made with thyme oil, with no harsh chemicals.
- Check again. We finish with an airflow and system check, and we show you the result, with photos whenever possible.
Every visit starts with a free Whole-Home Air & Attic Check. The technician confirms the price, you approve it, and nothing is added without your approval.
We do not promise health or energy results. Cleaning removes dust that has built up in the system, and results vary by system age, condition, and access. To learn more, see our air duct cleaning page, or book your free Whole-Home Air & Attic Check.
Sources
- EPA, “Should You Have the Air Ducts in Your Home Cleaned?” (seal registers and do not run the system during dusty work; HEPA vacuum; dusty return registers; what to expect from a provider; wet or moldy insulation): https://www.epa.gov/indoor-air-quality-iaq/should-you-have-air-ducts-your-home-cleaned
- NADCA, “ACR, The NADCA Standard,” 2021 edition (Section 1.6, inspection of components in construction, retrofit, and remodel projects; construction particulate as a condition for cleaning): https://nadca.com/sites/nadca/files/docs/2021/acr_the_nadca_standard_2021_edition.pdf
- EPA, “Renovation, Repair and Painting (RRP) Program: Consumers” (homes built before 1978 more likely to have lead-based paint; hire a lead-safe certified contractor): https://www.epa.gov/lead/renovation-repair-and-painting-rrp-program-consumers
