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It's a Westchester heatwave, the AC is running, but the house won't cool down. It feels almost as sticky and humid indoors as it does outdoors.

This is one of the most confusing HVAC problems; the system sounds like it's working, but it's just not doing its job. This article covers what to do when your AC is not working.

The Most Common Reasons Your AC Is Running But Not Cooling

Wondering, “Why is my AC not working?” These are the most common issues that affect your AC.

Clogged Air Filter Blocking Airflow

A dirty air filter starves the air handler of return air, causing the evaporator coil to ice over and the system to lose all cooling capacity. Essentially, the AC unit literally freezes. Restricted airflow means your AC won’t work well or at all.

Check your air filter before calling anyone. Here’s the typical replacement frequency:

1. 1-inch filters should be changed every 30 days
2. 4-inch filters should be changed every 6 months

Frozen Evaporator Coil

A frozen coil is often the downstream result of a clogged filter or closed supply vents. If you notice warm air coming from the vents even though the system is running, you may have a frozen evaporator coil.

A full evaporator coil can cause freezing. You also need to check your filter rating and compare it to your AC’s manual, verifying that your filter isn’t too restrictive for your unit. Once you identify the root issue, shut off your AC and let it thaw for at least 24 hours to be safe.

Low Refrigerant or an Aging R-22 System

Low refrigerant may signal a leak that a technician can repair. However, if your AC system is pre-2010, it may use R-22 refrigerant, also known as Freon, which is being phased out in the US.

Fixing refrigerant issues in an R-22 system is a temporary fix and can be more expensive in the long run.

Clogged Condenser Unit—Especially in Wooded Westchester Yards

Dense tree cover in Westchester towns like Pleasantville and Tarrytown may result in a condenser choked with debris that can't reject heat. The system runs, but the refrigerant never properly cools.

Voltage Fluctuations During Westchester Heatwaves

Con Edison, the NYC and Westchester energy company, has specialized in load management during peak heat events, which can reduce voltage on residential circuits. The issue is that under-voltage conditions prevent compressors from starting properly or cause them to trip mid-cycle.

You may notice the system short-cycling, meaning it’s cycling on and off without cooling. Fixing this requires a technician to diagnose compressor health.

When to Stop Troubleshooting and Call for AC Repair

Say you’ve checked the filter, confirmed the thermostat setting, and the system is still not cooling. It’s time to call an expert. Always call a professional if you have:

• Ice on the refrigerant lines
• Breaker tripping repeatedly
• System running non-stop without dropping the temperature
• A home over 85°F with elderly or young children present

Call T.Webber at (845) 443-4815 or schedule service online. We offer same-day emergency air conditioning repair and standard AC repair throughout Westchester and the Hudson Valley.

Why Westchester Summers Are Especially Hard on Air Conditioners

Westchester summers can be tougher on cooling systems than many homeowners realize. In July and August, Hudson Valley dew points often climb above 65°F, making the air feel heavy and harder to cool. Your AC not only has to lower the temperature but also must remove moisture from the air. Systems have to run longer and work harder to keep indoor spaces comfortable.

A system with dirty coils, low refrigerant, airflow restrictions, or aging components may still hit the thermostat setting but fail to dehumidify properly. The result is high indoor humidity, where the house feels sticky or clammy even when the thermostat reads 70°F. Homeowners often describe this as central air not working, even though the equipment is technically still running.

This also affects homes with heat pumps. If your heat pump is not cooling during muggy Westchester weather, the issue may be reduced capacity, airflow problems, or a need for maintenance rather than a complete breakdown. In humid conditions, even small performance losses become much more noticeable.

How to Keep Your AC Running All Summer—Without Emergency Calls

The best way to avoid mid-summer breakdowns is to schedule service before the hottest weather arrives. An annual AC maintenance visit can catch problems before they turn into emergency calls. Routine AC maintenance also helps your system run more efficiently during long Hudson Valley heatwaves. For year-round peace of mind, the Total Care Club is a smart way to stay ahead of summer breakdowns. Check out our special offers, as well.

If your AC is running but your home won't cool down, T.Webber's HVAC technicians are available 24/7 throughout Westchester, Dutchess, Putnam, and the Hudson Valley. Call (845) 443-4815 or schedule online.