Hurricane-season AC prep before and after the storm
Hurricane season in South Louisiana runs June through November. A central AC that survives a named storm still needs a pre-storm shutdown, a post-storm inspection, a flood-line call, and a clear DIY-vs-pro rule. The four-part checklist that protects the unit before the storm — and protects the homeowner after it.
A hurricane-season AC survives on the order of the shutdown and restart
A central AC built in the last 20 years can ride out a Category 1 or 2 storm with little more than a debris wash-down. The damage happens at the edges — wrong-power brown-outs cooking the compressor, floodwater reaching the contactor, a homeowner flipping the breaker back on while the indoor coil is still wet. The unit itself is sturdy; the prep and the post-storm inspection are the parts that decide what survives.
Treat hurricane-season AC work as two ordered checklists — pre-storm shutdown and post-storm inspection — plus two filters that decide which side of the work a homeowner can do: the flood line on the outdoor unit and whether the indoor coil touched water. Get those right and the unit usually survives; get them wrong and a small post-storm moment becomes an insurance conversation.
Pre-storm window
48–72h before landfall
Hours before a named storm hits South Louisiana when pre-storm AC shutdown should be finished
Outdoor flood line
<18in → salvageable
Inches of floodwater on the outdoor pad that still leaves the system salvageable
The two non-negotiables
Breaker stays OFF until indoor is dry. Indoor coil touched floodwater = a pro call, not a homeowner restart.
Rule of thumb: clean visual, dry air handler, no smells, no flooded condenser — safe to restart on a low-cool call. Anything outside that pattern is a tech call before a run cycle.
Four signals a hurricane brings that a normal comfort call does not
None of these are part of a typical summer service call. They are the four conditions that re-frame a normal AC question into a hurricane prep or post-storm recovery question — and that set the rule for which steps a homeowner can run and which need a tech.
Once a hurricane forecast puts Southeast Louisiana inside the cone with 48–72 hours to landfall, the AC prep window starts. The system is normally running hard right up to that point — and the shutdown has to happen in a deliberate order, not in a panic when squalls are already on the coast.
If standing water reached the concrete pad under the condenser, the controls, contactor, and lower coil fins likely took on contamination. Whether the unit survives depends on how high the line got — see the 18-inch rule below — but even shallow contact turns a normal restart into an inspection-first decision.
Repeated brown-outs and momentary surges while the storm was overhead are the most common cause of post-storm compressor damage. The compressor tries to start under load, the voltage sags, and the motor overheats — sometimes silently. A post-storm hard-start inspection is the right move before any prolonged run.
If the storm surge or flooding reached the supply boots, return grilles, or the air handler in the attic or closet, the call is bigger than the condenser. Floodwater in the duct system is a category-3 (black-water) contamination, and the ductwork itself may need professional cleaning — or replacement.
A six-step shutdown that finishes 48–72 hours before landfall
These steps run in this order — filter first, breaker last. The order matters: each step locks in a precondition for the next one, and reversing it (breaker first, filter last) is how post-storm damage shows up that should not have.
A pre-storm filter swap means the system goes into the storm with a clean, unrestricted airflow path. The filter that comes out is the one that gets thrown away at restart — storm debris, moisture, and a week of sitting can turn a borderline filter into airflow blockage on day one of cooling again.
Fresh filter before the storm = clean restart after it.
Let the system run a normal cooling cycle for about 5 minutes right before the shutdown sequence. This burns off surface moisture on the evaporator coil and gives the condensate drain a chance to clear the pan before the unit sits idle through the storm.
5-minute cooldown = dry coil going into the storm.
Pull out the phone and shoot: the equipment plate on the outdoor condenser (model, serial, install date), the air handler label, and a wide shot of the install. Insurance claims move faster with dated, geotagged photos filed before the storm — and you will forget the model number by the time the adjuster calls.
Photos before the storm = no insurance arguments after it.
Before any breaker work, tell the thermostat the system is done. Setting it to OFF first locks out the call for cooling, so nothing kicks back on while you are standing at the breaker with wet hands during a squall.
Thermostat OFF = no surprise restart while you work.
Wrap the small disconnect box beside the condenser in a plastic bag or dedicated weather cover to keep rain out of the pull-out handle and the fuse holder. Do NOT wrap the condenser coils — a wrapped condenser traps moisture against the coil and promotes corrosion.
Cover the box, not the coils.
The breaker is the single point that isolates the whole system. Flip the indoor air handler breaker (and the outdoor condenser breaker if it is separate) to OFF last, after every other step above. The breaker stays OFF through the storm and is not flipped back on until the post-storm inspection has cleared the unit.
Breaker OFF last, breaker ON last — same point, same reason.
Six inspection steps before the breaker flips back on
The post-storm order is the inverse of the pre-storm order — visual first, breaker last. Two non-negotiables sit between them: the indoor side has to be dry, and any metallic or burnt smell keeps the breaker OFF until a tech runs the inspection.
Walk the perimeter of the condenser. Look for: debris against the coil fins, a displaced or shifted pad, sheet-metal damage to the cabinet, a floodwater line on the cabinet or pad, fallen limbs or fencing pressed against the coil, and any sign that the disconnect box took on water. Photograph anything you find.
Do not flip the breaker back on yet. Before power returns, look at the indoor air handler, the drain pan, and the duct boots visible at the attic hatch or closet. If any of those shows standing water, the breaker stays OFF — running the blower across a wet coil redistributes contamination into every supply register.
Open the air handler access and look at the secondary drip pan under the coil. Standing water, slime, or an off smell here is the clearest post-storm signal that something failed during the storm. Pour a cup of distilled white vinegar down the condensate line to clear any algae blockage that opened during the outage.
Stand near the air handler with the blower access still open. A sharp metallic smell, ozone, or any burnt-insulation odor means an electrical component shorted during the storm. Do not energize anything that smells wrong — call the tech before you flip the breaker.
Even a pre-storm fresh filter may have pulled in storm debris and humidity while the system sat idle. Pull the old one out, install a clean replacement, and save the old filter in a bag — it is part of the post-storm record if anything downstream misbehaves.
Flip the breaker back ON, set the thermostat to FAN-ONLY, and listen for a clean 2–3 minute run. No odd sounds, no smells, no tripped breaker — then move to a low-cool call (78° setpoint, not 72°) for the first 30 minutes. Watch the Entergy meter or smart-meter app; a runaway amperage reading means the compressor is failing under load.
The 18-inch rule on the outdoor pad — and what changes above it
The most common post-storm question in South Louisiana is "how high did the water get on the condenser?" — and the answer has three zones. Below 18 inches, the system usually survives with inspection. Above 18 inches, the conversation changes.
A wet pad with no waterline on the cabinet is the safest case. The contactor stayed dry, the motor housing stayed dry, and the lower coil may have been hit lightly by splash. After a fresh-water rinse, a tech can hard-start the compressor and confirm draw.
Standing water reached the lower cabinet but did not pass the control box or contactor. This is the borderline case — the compressor likely survived but the electricals need a megger check and a hard-start amp test before any prolonged run.
Water reached the contactor, the fan motor housing, and into the lower coil assembly. This is not a service call; it is an insurance and replacement conversation. Anything past this line generally cannot be restarted safely after submersion.
Indoor half of the rule: any floodwater touching the evaporator coil, the secondary drain pan, or the duct boots is a category-3 (black-water) contamination. The blower cannot run across a wet coil — the call is a duct cleaning or replacement, not a filter swap.
What a homeowner can run, and what needs a tech — after a named storm
Post-storm, the DIY-vs-pro question is sharper than during a normal service call. The homeowner-safe steps match a clean visual and a dry air handler — anything outside that pattern crosses into a tech call.
A homeowner can safely run the post-storm filter swap, the condensate drain pour, the perimeter visual on the outdoor unit, and the breaker-on / fan-only step — as long as the air handler side is dry and nothing smells wrong. These are the steps in this guide that assume a clean visual and a clean nose.
If floodwater reached the evaporator coil, the secondary drain pan, or any ductwork boot, call a tech. Category-3 (black-water) contamination in an indoor coil is a cleaning-or-replacement decision, and a blower running across a wet coil spreads contamination through every supply register in the house.
A burning smell, ozone, a tripped breaker that will not reset, or visible scorch marks around the disconnect mean the post-storm hard-start resistance of the compressor is compromised. The call is a hard-start test, a megger check, and possibly an insurance documentation visit.
If standing water reached higher than roughly 18 inches up the side of the outdoor cabinet — above the control box, the contactor, and most of the lower coil — the electricals and motor have likely been submerged. This is a total-loss conversation with the manufacturer warranty and the homeowner's policy.
Hurricane prep is the seasonal cap on the comfort and cost guides we already wrote
The same houses we wrote about in the comfort, smell, duct, and replace-vs-repair guides are the houses hurricane prep protects. Every one of those conditions has its own page — and one good seasonal habit is to read all of them before the storm, not after it.
Quick stats — mental checklist before landfall
South Louisiana season
Hurricane season runs June 1 through November 30. The peak landfall band for Southeast Louisiana is mid-August through late September.
Brown-out damage
Repeated power blinking during a storm is the most common cause of post-storm compressor failure. A hard-start inspection is cheaper than a compressor swap.
Equipment plate photos
A pre-storm photo of the equipment plate and a wide install shot is the single biggest help in any post-storm insurance claim.
Breaker, last in, last out
The breaker is the single point that isolates the whole system. It flips OFF last in the pre-storm order and ON last in the post-storm order — same logic, same point.
Questions homeowners in your situation actually ask
The hurricane-season version of the same South Louisiana HVAC conversation — answers that assume a named storm has either just been forecast or just passed through.
Related reading
Comfort-side lens →
The indoor humidity and short-cycling problems a hurricane makes worse — run the comfort checklist before the storm, not after the first restart.
Musty AC smell →
A post-storm musty smell usually means the coil sat wet during the outage — the same mold physics, framed for storm-impacted drain pans and biofilm.
Attic duct diagnostics →
A storm that pushes surge into the attic compromises the duct side of the system too — disconnected boots and displaced flex are post-storm common calls.
Replace vs repair →
For an aging SEER-10 that needs a storm-recovery conversation AND a replace-vs-repair one, the four-question grid is the same — decide equipment first, hurricane prep second.
Replace vs repair HVAC →
The repair-cost / humidity-lifespan / scored-checklist version of the same decision — when $1,500 in 24 months and a single $2,000 repair flip the math on a 15-year-old SEER-10.