What Happens When an AC Unit Freezes and Leaks
Summer in North Carolina often brings long stretches of heat and high humidity. During these times, many of us instinctively lower our thermostats in hopes of quickly cooling our units. However, if an air conditioning system is already struggling to keep up, lowering the temperature too much can cause more harm than good.
Here’s what happens step by step:
1. The AC is set too low for the outside conditions
When an upstairs owner turns their thermostat far down in the middle of a hot, humid day, the system works nonstop to try to reach a temperature it may not be capable of holding. The coils can get too cold, especially if air flow is restricted by a dirty filter, closed vents, or high humidity.
2. Ice builds up inside the AC system
Instead of cooling the air properly, condensation on the coil begins to freeze. The ice spreads, wrapping the coils in a solid block of frozen condensation. The AC unit is then working harder, but cooling less and less efficiently.
3. The system shuts down or stops cooling
Eventually, the AC can no longer move air across the frozen coils. You’ll notice little to no air coming out of the vents, or the air will no longer feel cool. At this point, many owners think their AC has “broken,” when in reality it has frozen.
4. The thaw—and the water leak
Once the system is turned off or stops running, the ice begins to melt. That meltwater has to go somewhere. Often it overflows the condensate pan or drips into surrounding areas, which can mean leaks into the ceiling or walls of the unit below.
5. Risks for you and your neighbors
At Wafco Mills, where units share walls, ceilings, and floors, a frozen AC that defrosts can create damage not only in your unit but also in the one below you. Water stains, ceiling damage, or even mold can result. Under the Wafco Mills Declaration of Condominium and Bylaws, owners are responsible for damage that originates from their unit and affects a neighbor’s property.
6. Your responsibilities under NC Law and our Governing Docs
North Carolina Condominium Act (N.C.G.S. § 47C-3-107) states that unit owners are responsible for maintenance, repair, and replacement of their own systems and equipment serving only their unit.
The Wafco Mills Maintenance Responsibility Chart confirms that HVAC systems are the responsibility of each individual unit owner.
If a leak from your system causes damage to another unit or to the common elements, the cost of repair may be charged back to you under both the Wafco Mills Bylaws and NC real estate law.
Preventing AC Freezing and Water Leaks
Set a reasonable temperature. Try not to lower your thermostat more than 20 degrees below the outside temperature.
Change your filter regularly. A clogged filter reduces air flow and makes freezing more likely. Use a quality filer with a high MERV rating.
Schedule regular maintenance. Having a licensed HVAC technician inspect your system in the spring can prevent summer breakdowns.
Act quickly if you notice a problem. If air stops blowing cold or you see ice on your unit, turn it off immediately and contact your HVAC service provider.
Key Takeaway for Owners
If you notice water leaking in the summer months, it may be the result of a neighbor’s frozen AC defrosting. Please remember: each owner is responsible for maintaining their HVAC unit and for any damages caused if it fails. Preventive maintenance is always less expensive than repairs—both for your own home and for your neighbors.
For more information on maintenance responsibilities, please review the Wafco Mills Chart of Maintenance Responsibility and our community’s Declaration of Condominium available on the Owner Portal.
