We clean the ducts behind every vent

Every duct cleaning follows the same order

Every job starts with a look inside before anything gets cleaned. We take off a couple of vent covers and open the return, so we can see the filter and the blower cabinet. That shows where the dust is heaviest and whether any duct is torn or holding water. You get to see the inside of your own ducts, instead of taking someone's word for what is in there.

Next the whole system goes under suction. A large vacuum hooks to the main trunk, the big duct that feeds the smaller ones, and pulls air out the entire time we work. That way loosened dust moves toward the vacuum and away from your rooms. We then clean the supply ducts, the ones that blow air into the rooms, one vent at a time. Brushes and blasts of air knock dust off the duct walls, and the suction carries it down the trunk and out of the building.

Return ducts get the same work, and they usually need it more. The return is where indoor air gets pulled in, so it catches pet hair and fine desert dust first. We clean the return duct and its grille, then vacuum out the blower cabinet. Vent covers get washed before they go back on. When we finish, you turn the system on and no gray puff comes out of the vents.

• A look inside before any cleaning starts
• Whole system held under suction while we work
• Every supply duct cleaned back to the trunk
• Return duct and blower cabinet cleaned out
• Vent covers washed before they go back on

Phoenix heat keeps your system running hard

In most of the country an air conditioner gets a few months of work. Here in Phoenix it runs from spring well into fall, and on the worst afternoons it barely shuts off. The whole time it runs, it pulls the air in the building through the return and pushes it back out the supply vents. That is far more air and dust moving through the ducts than a building in a milder place ever sees.

Then the monsoon comes. Summer dust storms push a wall of dust across the Valley, and the fine grit gets in around doors and windows. Once it is inside, the return pulls it straight into the ductwork. After a rough storm season, the return side of a Phoenix system often has a gray lining you can spot with a flashlight. That dust is finer than ordinary indoor dust, and it packs into corners and bends.

Monsoon season also brings the muggiest weather of the year. The cold coil in your indoor unit pulls water out of the air, and that water runs into a pan and out a drain line. If the drain backs up, or a duct stays damp, the dust inside gives mold something to grow on. The EPA has said that ducts that are not kept up can collect dust and debris, and that moisture raises the chance of mold. So we check for wet spots on every job.

The type of building changes the job

Most newer buildings around Phoenix, from Gilbert and Chandler out to Surprise and Goodyear, are wood frame covered in stucco. Their ducts run through the attic, and much of that duct is flex: a plastic sleeve over a wire coil, wrapped in insulation. Flex tears under a stiff spinning brush, so we clean it with softer brushes and air. Summer attic heat also dries out the tape at the joints. A joint that lets go on the return side pulls attic dust and insulation straight into the building.

Older neighborhoods in central Phoenix and Tempe are full of concrete block buildings built on a slab. Many have metal ducts in a shallow attic, and some have ducts that run through the slab under the floor. Metal duct can take firmer brushing than flex. Ducts under the floor are harder to clean. They sit below the rooms, and they can pick up dirt or water that seeps in from the ground. We look down those runs with a light before we push anything through them.

Many flat-roof buildings in older parts of Phoenix have the air conditioner up on the roof. So do most office suites and restaurants around the Valley. In a commercial space the ducts usually sit above a drop ceiling. We get to the main trunk from the roof and reach the smaller runs by lifting ceiling tiles. At a restaurant, the return can also pull in grease from the kitchen. Grease turns loose dust into a sticky coat that takes longer to break free.

A skipped step puts the dust back

The first shortcut to watch for is cleaning with no suction on the system. Brushing a duct that way just pushes the dust along to the next vent. Some of it lands in your living room, and you see it the next morning as a fine gray film on the furniture. The vacuum has to be running before the first brush goes in, and it stays on until the last vent cover is back.

A second shortcut is cleaning the supply side and skipping the return. It looks fine at first, because the vents you can see are clean. The return feeds every one of them, though, so a dirty return lines the clean ducts with dust again before long. Dust that slips past the filter also settles on the blower and the cold coil. A coated coil makes the system run longer to cool the same building, which means bigger power bills and more wear on the parts.

Last is the vent-only job. Someone vacuums the grilles and calls it duct cleaning. Take a vent cover off afterward and shine a flashlight up past the bend, and the gray lining is still there. That is the check we want you to make after we leave. If we come across mold or wet insulation along the way, we will show you. Cleaning a duct does not stop the leak or clogged drain line that caused it.