Why Is My AC Not Cooling After Filter Change?

You may be shocked at how much dust and debris accumulates in air filters. Changing your air filters on a regular basis keeps dust and debris out of your air conditioner, preventing problems caused by clogged filters and ducts.

When your AC filter gets clogged, dust and dirt start getting into the air conditioner itself, causing wear and tear on the parts. You probably know what that means: the more wear and tear on the components, the sooner they wear out, and the sooner you deal with your AC breakdown.

The clogged filter also prevents enough air from flowing through the system to keep it working correctly. According to Energy Star, you should check and change the AC filter every month during peak season.

But there are instances when your AC fails to cool your indoor air even after the filter change. In this cases, there could be other causes for this failure.

Read this post to find out the possible causes of your ac not cooling after filter change.

Power supply

Sometimes, your ac not cooling after filter change is because it is not turned on. If there is electricity but your air conditioner is not turning on, check the breaker. You can reset it if it was tripped by flipping that switch.

Improper Settings are on Your Thermostat


You can help your AC work efficiently by keeping the thermostat set at a steady temperature. You must set the dial to a comfortable temperature but not too cold for the best efficiency.

The Department of Energy recommends having a fan on and setting the temperature at 78 degrees as the perfect energy-saving method. So the AC unit may have to kick on and off constantly all day to keep the temperatures low.

Check Your Circuit Breaker

Breakers always trip, but when your AC isn’t blowing cold air, your mind may think of the worst. Your air conditioning unit connects to two circuit breakers; one is for the outside and the second for the inside unit.

If the outside circuit breaker trips and the inside breaker is still working, the air won’t be cooled.

Reset the circuit breaker, and if it happens again, wait to reset it as it could cause damage to your AC.

Dirty or Wrong Size Air Filter


AC not cooling after filter change is also because of the smaller filter size. Probably the AC is running but not cooling the house. Maybe the filter you placed was dirty, the wrong size, or you’ve delayed changing it. Still, to add, the AC blower must work even more complex than usual, which can lead to internal damage.

So, for maximum results, replace your filter every three months on average, but inspecting it monthly during periods of high pollen counts or significant dust is also a good idea.

The frequency with which you change your filter isn’t the only reason your air conditioner isn’t blowing chilly air but is still functioning. Your air conditioner may also be overworked if you utilize the improper size air filter. Always double-check that the correct filter size is purchased for the unit’s make and model.

If the old filter you’re changing does not have labels with the size, take a tape measure or ruler and measure by looking at guidelines on how to measure your air filter.

Faulty Switch

When the blower continuously pushes cooled air through the ducts, your air conditioner performs well. This means that the chilly air remains in the system, causing internal components to freeze or potentially stop working. The main cause of weak airflow is a clogged air filter or faulty fan switch.

If a filter change does not fix the problem immediately, you may need a licensed HVAC professional to perform additional diagnostic tests.

Closed Vent Flaps


Closed vent flaps are another reason for your ac not blowing cold air after changing the filter.

The AC unit uses exterior vent flaps to free warm air and moisture from the cooling process. When the vent flaps are changed to the closed position, the warm air stays in the case and propels the system into overdrive.

When this occurs, you will see that the air getting out of your interior vents feels warmer than usual.

Wrong Unit Size

When you buy a new AC, it is viable to match its size to the square footage of your home to limit overworking the system.

An incorrectly sized air conditioner may work too hard and too long as it tries to cool the space. This will make it develop premature wear and damage, which often leads to the failure of internal parts.

Clogged Drain Lines

The drain lines in the AC unit become clogged with debris over time. When the drain lines become clogged, the air conditioner is unable to remove enough moisture from the air to cool it to the desired temperatures, resulting in your home’s central air conditioner not blowing cold air.

As part of your routine maintenance, make sure to empty out the drain lines so that your AC unit can continue to produce cool air. If you are not sure of the location of your drain line, contact an expert who may be able to show you the location of your drain line.

Un-insulated Ducts


Your ac not working after filter change is also a result of damaged insulation of your air conditioner ducts. When the air ducts are insufficiently insulated, the cooled air can make the temperature increase before it enters the room.

Since wildlife like squirrels and raccoons can take this material from the ducts, be sure to double-check the insulation frequently to avoid accidentally overworking the cooling system.


Although regularly changing your air filter is an excellent way of keeping your AC unit working adequately, there are other things to consider. For example, your fan setting, filter, and breaker can be the reasons why your AC isn’t blowing cold air.

Other problems include faulty condenser coils, refrigerants, compressors, or wiring. You can prevent these issues with regular maintenance, cleaning the coils and condensate drain line, and calling a technician twice a year to inspect.

Nevertheless, if freezing continues to occur after using the above tips, your heating and cooling system may require proper diagnosis and repair by a certified HVAC technician. If you’d like to learn more about these solutions, check out Anderson Air.

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