AC Not Cooling? 7 Common Reasons and Quick Fixes

If the AC does not cool on a hot day, you may feel discomfort. The house feels warm and the power bill keeps going up. Many homes in Canada and the US rely on air conditioners to stay comfortable. In fact 68 percent of households in Canada use an AC unit during summer. With so much use it is no surprise that common problems show up.

In this blog, Lew Plumbing will walk you through the most common reasons for an AC not cooling.

Dirty or Clogged Air Filter

One of the most common reasons for an AC not cooling is a dirty filter. It blocks the flow of air. When that happens the system struggles to push cool air through the vents. The unit works harder but the house still feels warm.

The good news is that this fix is simple. 

• First, switch the unit off to stay safe
• Next, pull out the old filter and see how much dust it holds
• When the filter looks clogged place a fresh one in its spot

A clean filter keeps air moving well and helps the system run smooth. Most homes need a new filter every one to three months. You can learn more about when and how often to clean your filter in our guide How Often Should You Clean Your Air Conditioner Filter.

Thermostat Problems

Sometimes the issue is not inside the unit at all. A faulty or poorly set thermostat can also leave the AC not cooling. If the thermostat is on the wrong setting the system will not cool down the space as it should.

To fix these issues, 

• Check the display first
• Make sure the mode is set to cool 
• If it is set to “fan” or “heat,” change it 
• Next look at the batteries

Weak batteries can cause the screen to go blank or give wrong signals to the AC. Lew Plumbing can test the device, repair AC faults or replace it if needed.

AC Fan Not Working

The fan inside your AC helps move cool air through the vents. If the fan stops the air will not reach the rooms. You may hear the unit run, yet no air comes out of the vents.

• First check if the breaker has tripped. 
• Flip it back if needed. 
• Next, look at the fan blades. 
• Dirt or small objects can block the blades. 
• Clear them with care if you see anything stuck.

If the fan motor does not turn on, the problem may be more complex. It could be a bad motor or a loose wire. At that point call Lew Plumbing. A pro can test the motor and fix it safe.

Low Refrigerant Levels

Refrigerant is the gas inside your AC that makes the air cool. If the level drops the unit blows warm air instead of cold. You may also hear hissing or see ice on the coil. These are signs of a leak.

Low refrigerant is not a problem you can fix yourself. It needs special tools and training. Only a licensed tech can find the leak and add the right amount of gas

Frozen Evaporator Coils

If it gets covered in ice your system will not cool the rooms well. Weak airflow is one of the first signs. You may also see ice on the coil or near the lines.

• First, turn the AC off and let it thaw. 
• Do not try to scrape the ice off because that can harm the coil. 
• If the coil freezes again, the problem is deeper.

Leaking AC Unit

When your AC leaks the trouble is more than warm air. Water that drips near the unit can harm your floors and walls. A musty smell or wet spots near the system often point to a leak.

The cause may be a blocked drain line or coils that froze and then thawed. Both issues cut down cooling and may lead to mold in the home. The best step is fast repair. Lew Plumbing can check the unit fix the source before the leak spreads further.

Blocked or Dirty Condenser Unit

The condenser unit sits outside your home. It needs clear airflow to work well. If dirt, leaves, or grass block it, your AC runs but the air inside feels warm.

A simple check helps here. 

• Look around the unit and clear any leaves or debris. 
• You can also rinse the fins with gentle water to remove dust. 
• If the AC still does not cool there may be a bigger issue inside the system. 

Call Lew Plumbing to inspect and clean it safe.

FAQs

Why is my AC not cooling even though it runs?

frozen coils, or a fan that does not spin can also cause the issue. If basic checks do not fix it you need a pro from Lew Plumbing to look deeper.

Can I fix a leaking AC unit myself?

Small steps like clearing dirt from the drain line may help, but leaks often point to bigger issues such as frozen coils or blocked parts.