Hurricane season and your HVAC: before, during and after a storm

What should you do before the season starts?

Atlantic hurricane season runs from June through November. The useful preparation happens before anything is in the forecast:

• Have the cooling system serviced in spring, so a storm does not find a weak capacitor or a blocked drain
• Check that the outdoor unit is fastened to its pad; coastal installations often use tie-down straps
• Photograph the indoor and outdoor equipment and their model and serial labels for insurance
• Know where the outdoor disconnect and the breaker for the system are
• Fit carbon monoxide alarms on every level and outside sleeping areas, and test them

What should you do when a storm is coming?

Bring in or tie down anything that could become debris near the unit — patio furniture, grills, planters. Wind-driven objects do more damage to condenser fins than rain does.

If flooding or storm surge is possible and it is safe to do so, turn off electricity at the breaker. Ready.gov's advice is blunt: do not touch electrical equipment if it is wet or you are standing in water.

A cover over the outdoor unit does little against wind-driven debris, and it must come off before the system runs again. Securing the unit and clearing what is around it does more.

How do you run a generator safely?

The Consumer Product Safety Commission's rules are specific: operate a portable generator outdoors only, at least 20 feet from the house, with the exhaust pointed away from windows, doors and vents. Never run one in a garage, a basement, a crawlspace or on a porch, even with the doors open.

Install battery-operated carbon monoxide alarms, or alarms with battery backup, on every level and outside sleeping areas, and test them monthly. If an alarm sounds, get outside first and then call 911.

Most portable generators cannot run a central air conditioner. Connecting a generator to the house wiring needs a transfer switch installed by a licensed electrician — never plug one into a wall outlet.

What if water reached the equipment?

Do not turn it on to see whether it works. AHRI, the industry body for heating and cooling manufacturers, advises that flood-damaged equipment should be replaced rather than repaired, and that inspection should be done by qualified contractors, not by homeowners.

Gas furnaces are the most serious case: their gas valves and controls are especially vulnerable to water, and the damage is not always visible. The CPSC advises having gas control valves, wiring, circuit breakers and fuses that were under water inspected and replaced by a qualified professional before use.

Ductwork that sat in floodwater, in a crawlspace or an attic that took water through the roof, usually needs cleaning or replacing as well — it will otherwise circulate what the water left behind.

What if the unit was knocked about but not flooded?

If the outdoor unit has shifted on its pad, even slightly, the refrigerant lines may have been strained or cracked. Have it checked before running it. Power surges during a storm also take out capacitors and control boards; if the system starts but makes new noises or does not cool, switch it off and call.

What helps with the insurance claim?

Photograph the damage before anything is moved or repaired, keep receipts, and ask the technician for a written assessment of what was found and why. A dated description of the equipment's condition is far more useful to an adjuster than a verbal one.