Rusted AC Unit? How Salt Air Corrodes Outdoor Units in South Florida

If you live anywhere near the coast in Broward County, your outdoor AC unit is fighting salt every day. This condenser is a good example of what years of salt air and moisture can do. Here’s how corrosion happens, what to watch for and how to slow it down.

Why salt air is so hard on AC units

Ocean breezes carry tiny droplets of salt water inland, often for miles. Salt settles on your condenser’s coil fins, copper tubing, cabinet and electrical parts. Add Florida humidity and rain, and you get a constant cycle of wet and dry that speeds up corrosion. Homes along the beach, the Intracoastal and the canals get the worst of it, but we see corrosion well west of US-1 too.

Warning signs of corrosion

• Rust on the cabinet, especially along the base and corners
• Coil fins that look white, flaky or crumble when touched
• Green or white crust on copper lines and fittings
• Refrigerant leaks, which show up as weak cooling or an AC that needs recharging again and again
• Repeated failures of capacitors, contactors and other electrical parts

What corrosion leads to

As fins corrode, they stop moving heat efficiently, so the system runs longer and costs more to operate. Corroded copper eventually develops pinhole leaks. Corroded electrical connections get hot and fail. And when the coil itself is too far gone, replacing it often costs enough that replacing the whole system makes more sense. Many coastal units are worn out well before the 12 to 15 years we’d expect inland.

How to protect your outdoor unit

• Rinse it regularly. Turn the power off at the disconnect, then gently rinse the coil with fresh water from a garden hose every month or two. Never use a pressure washer, which flattens the fins.
• Keep sprinklers off it. Sprinkler water, especially from wells, leaves mineral deposits that make corrosion worse.
• Keep the area clear. Leave about two feet of open space around the unit so it can breathe and dry out.
• Schedule maintenance twice a year. A professional coil cleaning and a check of the electrical connections catches problems early. Our AC maintenance service includes both.
• Ask about coastal-rated equipment. When it’s time to replace, some manufacturers offer coated coils and corrosion-resistant cabinets built for coastal areas.

When it’s time to replace

If your unit has repeated leaks, a badly corroded coil or a rusted-through cabinet, putting more money into it rarely pays off. Here’s the same spot after we replaced the corroded condenser above with a new system:

Hurricane season adds its own risks for outdoor units; see our hurricane season AC tips. If your coastal unit is showing rust or losing cooling, call Bentley HVAC for an honest repair assessment. We serve coastal neighborhoods in Fort Lauderdale, Pompano Beach and Hollywood, and we’ll tell you straight whether a repair or a replacement makes more sense.