Two surfaces, two problems

In a conventional apartment the ducts hide above a drywall ceiling. In many RiNo lofts and newer industrial-style buildings they hang in plain view: round galvanized pipe, sometimes painted, running along the beams with diffusers dropping down at intervals. The outside of that metal sits right in the layer of warm air near the ceiling where smoke collects, so it picks up a tacky coating that also catches dust. You can often see it as a dull brown haze on what should be shiny steel.

The inside matters more for odor. When someone smokes in a unit with the heating or cooling running, the return pulls smoke-laden air through the filter, the air handler and the supply ducts. Some of it sticks. Afterward, every time the system starts, warm air passes over that film and redistributes the smell to every room. Changing the filter helps but does not touch what has already coated the coil, the blower and the ducts themselves.

Working through the duct system in order

Start at the parts you control and move toward the parts that need a professional or building approval.

  1. Find out what you have.Is the unit served by its own furnace or fan coil, a heat pump in a closet, or a central building system? Your lease, HOA documents or the building manager can tell you. This decides who is responsible for the ducts.
  2. Replace the filter, then replace it again.Install a new filter of the rating the equipment is designed for. After deep cleaning the rest of the unit, replace it a second time, since the first one catches the residue knocked loose during cleaning.
  3. Clean the outside of exposed runs.Wipe galvanized or painted duct exteriors with a degreasing cleaner, top surfaces first. A soot sponge can remove dry film before anything wet is used. Protect the floor below from drips.
  4. Remove and wash diffusers and return grilles.These are usually held by a few screws and come down easily. Washing them in a tub removes a lot of concentrated film from the air path.
  5. Have the inside assessed.Interior duct cleaning, coil cleaning and blower cleaning are specialist work. Ask the provider to show you before-and-after photos of the inside of your own ducts, not generic images.
  6. Run a whole-space treatment with the system on.If a whole-space odor treatment is used, ask whether the air system will run during it so the treatment reaches the ductwork, and whether the building allows that if ducts are shared.

Questions for a building manager before duct work

In condos and apartments, ducts may serve more than one unit or connect to shared exhaust.

  1. Does any duct, return or exhaust shaft in this unit connect to another unit or a common corridor?
  2. Who maintains the air handler or fan coil for this unit, and when was it last serviced?
  3. Are there fire dampers in the ductwork that a cleaning provider must not disturb?
  4. Is a whole-space odor treatment allowed if it runs through the air system, and does it need notice to neighbors?
  5. Can maintenance staff confirm the filter size and rating the equipment needs?

Common questions

Can I paint the exposed ducts to seal in the odor?

Painting the outside can cover film on the exterior once it has been cleaned, but it does nothing for the inside of the ducts, which is where most of the odor that moves through the unit comes from.

General information for RiNo, not a quote or professional advice. In an emergency, call 911.