Professional Evaporator Coil Services in Durham, NC

A frozen evaporator coil isn't usually a catastrophic emergency, but it is urgent. Your AC will not cool your home while the coil is frozen, and letting it run in that condition can damage the compressor — which turns a $200-$800 coil repair into a $2,000-$4,000 compressor replacement. If you see ice on the indoor unit or the refrigerant line, turn the system off immediately and call for service.

Frozen coils are one of the top three summer AC calls our techs see in Apex and Cary, and the Triangle's humidity makes coil problems more common here than in drier climates.

What Causes a Coil to Freeze

The evaporator coil sits inside your air handler and absorbs heat from the air blowing across it. When something disrupts that process, the coil drops below freezing and ice starts building up. There are a handful of common causes, and they range from simple fixes to more serious repairs.

Restricted airflow is the most frequent culprit. A dirty filter, closed vents, or a failing blower motor reduces the amount of warm air passing over the coil. Without enough warm air, the coil gets too cold. We see this constantly — a homeowner forgets to change the filter for six months, and the system freezes up in July. Checking and replacing your filter every 30 to 90 days prevents this entirely.

Low refrigerant is the second most common cause. When refrigerant levels drop (almost always due to a leak), the remaining refrigerant expands too much and supercools the coil. This is a professional repair — the leak has to be found and fixed before recharging, or the problem comes right back.

A dirty coil itself can cause freezing. Dust, pollen, and grime accumulate on the coil surface over time, creating an insulating layer that traps cold in instead of letting it transfer to the air. Triangle homes deal with this faster than homes in other regions because our combination of humidity, pollen, and long cooling seasons means the coil processes more dirty, moist air per year.

A malfunctioning blower motor or fan that's running at reduced speed creates the same effect as a clogged filter. Less air across the coil, more ice formation.

A faulty expansion valve or metering device can send too much refrigerant into the coil at once, dropping the temperature below freezing.

What to Do When You Find a Frozen Coil

Step one: turn off the AC at the thermostat. Let the fan run by switching from "auto" to "on" — this pushes warm air across the coil to help it thaw.

Step two: check your air filter. If it's clogged, replace it. In about 30 percent of frozen coil calls, the filter was the entire problem.

Step three: wait one to three hours for the coil to fully thaw. Don't chip ice off the coil — the fins are fragile aluminum and bend easily, which creates more airflow problems.

Step four: once the ice is gone, turn the AC back on and monitor it. If it freezes again within 24 hours, you have a refrigerant or mechanical issue that needs professional diagnosis.

When to Call a Tech

If the coil refreezes after you've replaced the filter and given it time to thaw, something else is wrong. Our $49 diagnostic covers a full inspection of the coil, refrigerant levels, airflow measurements, and blower motor performance. We identify the root cause and fix it the same day in most cases.

Call immediately if you see water damage around the air handler. A frozen coil that thaws can overwhelm the drain pan and condensate line, sending water into your ceiling, walls, or floor. In Triangle homes with attic-mounted air handlers — which is most of them — this can cause significant drywall damage before you even notice the leak.

Coil Cleaning and Maintenance

An annual cleaning prevents most coil-related problems. During a tune-up, our techs inspect the evaporator coil for dirt buildup, check the fin condition, clean the coil surface with an approved solution, and verify proper airflow. In the Triangle's environment where humidity and pollen combine to create faster buildup, annual cleaning is especially important.

If the coil is heavily soiled and a surface cleaning won't restore performance, we can do a deep chemical cleaning. In rare cases where the coil has corroded, developed pinhole leaks, or been physically damaged, replacement is the better path. We'll show you what we find and let you make the call.

Coil Replacement

Evaporator coils do eventually wear out. Corrosion from years of condensation, chemical exposure from cleaning products, or leaks from manufacturing defects all shorten a coil's life. Replacement involves removing the old coil from the air handler, installing a matched replacement, evacuating and recharging the refrigerant, and testing the full system.

The coil has to match your outdoor condenser unit in capacity and refrigerant type. Mismatched coils cause efficiency losses and can void manufacturer warranties. Our techs verify compatibility before ordering parts.

Element Service Group serves the Triangle area with same-day coil inspections and repairs. We're veteran-owned, we've earned over 700 five-star reviews, and our techs carry the common parts and refrigerant to handle most coil issues in a single visit.