HVAC cleaning after a Preston Hollow fire

Large homes commonly have three, four or more air handlers, serving separate wings, floors, a guest house or a wine room. The fire may have started in one zone, but smoke does not respect those lines. It moves through stairwells and open halls to reach return grilles in other zones. Start with the system that served the fire area, then inspect each of the others, with notes and photos for each one. Do not assume that a unit is clean just because its rooms look fine. A filter and a look at the coil can show whether it took in smoke.

Ask for a simple table, listing each unit, the area it serves, what was found, what was cleaned and what was replaced. That one page helps your adjuster and also helps you later, when a smell shows up in a certain room and you need to know which system serves it.

Some homes have whole-house air filtration, humidifiers, dehumidifiers, UV lights or fresh-air ventilation systems. Each of these can hold residue or spread it. Filters should be replaced, and media may be ruined. Humidifier pads should be discarded. Fresh-air intakes may have pulled in smoke from outside and sent it straight into the house. Smart thermostats and zone controllers should be checked by a technician before use, as they could restart a system automatically. Turn these controls off, or set them to hold, until the job is finished.

Long duct runs in large attics are common, sometimes with flexible duct across great distances. Smoke rising into the attic can settle on the outside of ducts and in the insulation around them, and heat can soften or tear flexible duct jackets. Duct that held heavy smoke or was damaged is usually replaced. Metal duct can often be cleaned. Attics under complex roofs may be tall in one place and tight in another, so the crew may need several access points. Ask how insulation and ceilings will be protected as they move around.

Older homes may have hidden chases, old ductwork and materials that may contain asbestos ^[3], including wrap on old ducts and pipes. Test before anything is disturbed. Decorative grilles can often be removed, cleaned and refitted. If a system was added to an older house during a remodel, ask for a tracing of where it runs. Do not let anyone cut into paneling or plaster without talking to you first, as a better access point often exists.

Registers may be set high on walls or in coffered ceilings. Linear slot diffusers in modern rooms can be hard to reach and may hide dirty plenums behind them. Scaffolds or lifts may be needed. Take care with wood ceilings, plaster detail and stone, since dirty air can leave a dark mark around a grille, called ghosting. Ask how those marks will be cleaned, and whether finishes can be protected while the ducts are being worked on.

Gas furnaces and boilers exposed to heat, smoke or water should be checked before use. Gas restoration is a job for Atmos Energy or a qualified technician ^[4]. Wine room cooling, server closets and art storage rooms may have their own systems, and these often need attention first, since what they protect is sensitive to temperature. Replacing major equipment generally needs mechanical permits from Building Inspection ^[5]. Ask your contractor to allow for lead times on specialty units.

On a large job, several trades work at once. If drywall is being cut or floors sanded while ducts are being cleaned, dust goes right back in. Seal the registers and keep systems off during dusty work. Clean the ducts late in the sequence, then change filters more than once in the following weeks. Ask your single point of contact to schedule this, and check whether the air was tested or inspected before art and fine furniture return.

Ask whether the crew has handled homes with several air systems, and whether they will work with your regular HVAC company. Good results often depend on someone who knows how the zones are wired and controlled. Ask how they plan to protect finished ceilings and stone floors, and who will reseal any access panels. Find out how they will document each unit, and ask for inside-the-duct photos taken before and after. Be cautious with anyone quoting a single quick visit for a house of this size. Several systems, tall rooms and long attic runs take time, and rushing tends to leave whole branches untouched.

Ask as well how the work will be staged around other trades, and what happens if a smell shows up once the systems run together. A written answer now is far easier to act on than an argument later, when crews have moved to another job.