Salt Air and Coastal AC Corrosion

Who is most exposed

Sarasota County has barrier islands with Gulf beaches along most of its coast (Wikipedia: Sarasota County, Florida). Homes on Siesta Key, Longboat Key, Lido Key, Casey Key and Manasota Key, and those along Sarasota Bay and Lemon Bay, sit closest to salt spray. Corrosion tends to drop off with distance inland, but onshore winds and storms carry salt farther than many people expect.

What salt does to an AC

• Coil fins. The thin aluminum fins on the outdoor coil corrode first, turning white and crumbly. As they break down, the coil loses its ability to shed heat, so the system works harder.
• Coil tubes. Where copper tubes meet aluminum fins, galvanic corrosion can lead to pinhole leaks and lost refrigerant.
• Cabinet and fasteners. Steel panels, screws and brackets rust, and rusted mounting can weaken storm anchoring.
• Electrical parts. Contactors and terminals corrode, causing intermittent starts.

Slowing it down

• Rinse the coil. With the power off at the disconnect, a gentle rinse with fresh water from a garden hose removes salt buildup. Avoid high pressure, which bends fins.
• Regular service. Coastal units benefit from more frequent checks of the coil, electrical parts and fasteners. See maintenance.
• Placement. Where it is possible, a spot sheltered from direct Gulf wind helps, as long as the unit still has room to breathe.

Choosing equipment for the coast

When replacing a coastal system, ask about corrosion-resistant options: coated coils, all-aluminum coil designs, and stainless or coated fasteners and cabinets. Some manufacturers offer seacoast versions of their condensers. Ask how the warranty treats coastal installations, since some limit coverage close to salt water. See AC replacement.

Mounting and storms on the keys

Barrier-island homes are often raised, and condensers sit on elevated platforms. The Florida Building Code addresses wind anchoring and, in flood zones, elevation of equipment (Florida Building Commission (Florida Building Code)). Corroded straps and brackets should be replaced. The Town of Longboat Key and Sarasota County handle permits for their areas (Town of Longboat Key).

After storm surge

A unit that sat in salt water usually has salt in places a rinse cannot reach. Replacement is often the more reliable choice. The old refrigerant must be recovered under EPA rules (U.S. EPA, Section 608 refrigerant management).

Signs your unit is suffering

• White, powdery or flaking fins.
• Rust streaks on the cabinet.
• Cooling that drops off year after year.
• Repeated refrigerant leaks.

Related pages: ac replacement & new systems, ac maintenance & tune-ups, ac repair, and what shapes an estimate.

Sources: Wikipedia: Sarasota County, Florida; Florida Building Commission (Florida Building Code); U.S. EPA, Section 608 refrigerant management; Town of Longboat Key.