Why Is My AC Running but Not Cooling?

The scene: You live in an area such as Naperville, Aurora, Oswego or Plainfield. It starts getting a little stuffy inside. You open the windows to let in what appears to be a light breeze, but after a bit, you’re still uncomfortable. You close the windows, set the thermostat to the desired cooler temperature and hear the AC turn on.

Nothing really changes. You go to a vent and hold your hand in front of it: The air is blowing but it isn’t cool. What could be wrong?

Air Conditioning Repair

None of us like to be surprised by warm air from our air conditioner when we’re expecting cool air for comfort. It might even have us searching for “air conditioner repair near me” before we can say “where are my shorts?”

In this discussion, we’ll review some ways you can troubleshoot and possibly fix the issue yourself. We’ll also point out when you should contact an HVAC professional about returning your system to its proper function.

Need Air Conditioner Repair Near Me Common Cause 1: Crowded Outdoor Unit

If obstructions and debris have built up around the outside air conditioner – especially during winter – it can limit its ability to cool the refrigerant. Be sure to inspect the immediate surroundings and clear away anything that might be interfering with the unit.

Need Air Conditioner Repair Near Me Common Cause 2: Air Filter

Unless we have a great memory or our own way to track it, many of us can forget how long it’s been since we last replaced the filter.

A dirty filter is a leading reason for AC running but not cooling, because it restricts the airflow over the evaporator coils, which cool the air for recirculation into your spaces. Restricted airflow can also make the coils get too cold and form frost or ice, which slows the air even more. This in turn can overwork the unit’s motor, so be sure to clean or replace the air filter regularly.

(Another thing to watch for in this area is a defective fan motor. If the fan isn’t running or is too slow, it too can lead to restricted airflow and frosty coils, resulting in air that won’t cool. This would require an inspection by an HVAC professional.) 

Need Air Conditioner Repair Near Me Common Cause 3: Thermostat

If the AC is still running but not cooling after you check the outdoor unit and the filter, try the thermostat.

First, verify the thermostat is set to AUTO. If the AC is set to ON, the blower will continue running regardless of the chosen temperature, and it can seem like your system isn’t working because the fan is running without creating cool air. Setting the therm to AUTO lets the system monitor desired and actual temperatures and turn the blower off once your setting is reached.

If you have a programmable thermostat, double-check that it wasn’t set to reduce cooling at the time when you currently want cooler air.

The setting also should be at least five degrees under the room temperature. If it isn’t, lowering the setting can activate the compressor, which circulates the refrigerant between the inside and outside units to cool the air.

If these steps don’t correct the problem, there could be an issue with the temperature control system’s ability to communicate with the compressor. In this case, contact an HVAC professional for more information.

Need Air Conditioner Repair Near Me Common Cause 4: Low/Leaking Refrigerant

Refrigerant is the vital substance for cooling your air, so if there isn’t enough of it, you won’t be able to modify the temperature.

Low refrigerant usually means there’s a leak in the lines that carry it. Signs that your refrigerant is leaking can include a bubbling or hissing noise, a build-up of ice on the outside refrigerant line, and AC that doesn’t cool your spaces on hot days but does on cooler days or at night.

Handling refrigerant can be hazardous, so you will want to have an HVAC professional check and repair any leaks.

Here for Answers and Service

When your system suddenly isn’t working right, we understand you want a swift solution. If you ever have questions about AC that’s running but not cooling, we can help. Simply call (630) 585-6444 to speak with a Beery Heating and Cooling technician.

We are available for skilled, attentive service throughout the area, including Yorkville, Batavia, Plano, Lombard, Bolingbrook and Montgomery.