6 Quick Fixes for an AC Not Blowing Cold Air

Quick Fixes for an AC Not Blowing Cold Air

To fix an AC not blowing cold air:

  1. Check if your aircon is even operational
  2. Look for refrigerant leaks
  3. Clean air filters
  4. Clean evaporator and condenser coils
  5. Ensure that your airflow is not blocked
  6. Recalibrate your thermostat settings

Read along for more details.

Article Summary

  • Regular maintenance, including checking the operation of the air conditioning unit, proper refrigerant levels, and clean air filters, is essential for efficient cooling and preventing mechanical issues.
  • Refrigerant leaks can lead to higher energy costs, reduced efficiency, and even complete system failure if not addressed promptly, indicated by hissing sounds, ice formation, and reduced cooling capacity.
  • Ensuring unobstructed air flow by checking for blocked registers and ensuring duct integrity, as well as correctly sizing your AC unit prevents inefficiencies and uneven cooling.

Check If Your AC Unit is Running

First, see if your AC is even functioning.

This might seem obvious, but sometimes, the most glaring issues are the easiest to overlook.

Check for the humming sound of the compressor or the fan spinning. If these signs are absent or if you hear unusual noises, it could indicate a mechanical issue.

Also, make sure your circuit breaker hasn’t tripped. That’d cut off power to your air conditioning unit.

Conduct a manual inspection. Look for visible signs of damage. Any dents in the fans or external condenser damage.

These could be telltale signs of internal mechanical issues. Verifying the air conditioner operation is critical to identify and address the root problem accurately.

Look for Signs of Refrigerant Leaks

Refrigerant Leak Signs

You can detect refrigerant leaks by looking and listening to the following signs:

  • Hissing or gurgling sounds can be a dead giveaway that refrigerant is escaping from the coils.
  • Look for ice formation on the outdoor condenser.
  • Strange noises like hissing or bubbling from the unit can also indicate potential leaks.

Loss of cooling capacity in your aircond can also be a sign.

If you notice a puddle around the indoor unit, it could be a sign of frozen coils thawing and dripping.

Sometimes, you might also find an oily residue around the AC.

Understanding Refrigerant’s Role

Your AC cools because of the refrigerant in it. Hence the name “refrigerant”. Duh!

It extracts heat from the indoor air. The compressor circulates it between the evaporator and condenser coils.

What Happens If You Ignore This

Working your aircon with low refrigerant levels can increase energy costs and reduce efficiency.

It can also cause insufficient lubrication for the compressor. This can cause mechanical issues in the compressor or even failure.

Over time, a small leak can drain all of the refrigerant. Your AC will stop functioning and require significant repairs or replacement.

So, if your AC is blowing warm air instead of cold, get it checked!

Clean the Dirty Air Filters

It seems like a small matter, but it’s not. An unclean air filter is usually what is causing an air conditioning system not to blow cold air.

Frequency of Filter Changes

Home AC filters should be replaced at least once every three months.

But, if you’re a pet owner or anyone in your home has respiratory conditions or allergies, the change needs to be more frequent.

Clean the dirty air filters for ductless AC every two to four weeks and replace them annually.

Risks of Negligence

A clogged air filter can cause your air conditioner to:

  • work harder
  • lead to potential breakdowns
  • result in frequent and costly repairs
  • cause damage to parts of the AC, like the evaporator coil

This reduced efficiency can result in higher energy bills. You don’t want that now, do you?

You also get poor indoor air quality if you don’t change your air filters because built-up contaminants will no longer be trapped effectively.

Worst of all, a clogged air filter can cause the evaporator coil to get colder, freeze up, and stop working. This severely impacts the AC’s ability to produce cold air.

Clean the Evaporator and Condenser Coils

Coil Maintenance

The evaporator and condenser coils absorb heat from the indoor environment and release it outside.

And they need regular maintenance to function optimally.

This is how you can clean them:

  1. Turn off the power to the AC.
  2. Remove any visible debris from the coils by hand.
  3. Gently wash the coils with a solution of soap and water.
  4. Use a fin comb to straighten any bent aluminum fins on the condenser. This will improve airflow and overall efficiency of the air conditioner.

For the evaporator coil, first, you gently brush it with a nylon brush to remove debris. Then, apply a foaming coil cleaner for thorough cleaning.

Regularly cleaning these coils can prevent corrosion and leaks. This can remedy an AC not blowing cold air.

Problems You Can Face

Evaporator coils can experience problems like cracking and freezing. They lead to efficiency losses and system breakdown.

Dirt buildup on these coils can cause the system to cycle room-temperature air or shut off prematurely.

Similarly, if your AC is blowing warm air, this could mean condenser coil issues.

Poor cooling performance and extended room cooling times can result from a faulty or dirty condenser coil.

If you notice ice or frost on the condenser or evaporator coil, this is a sure sign that you need to call a pro.

Make Sure the Air Flow is Not Blocked

Blocked Air Circulation

This topic is for you if you have central air conditioning; proper air circulation is vital even if your air conditioning unit functions perfectly.

If you experience weak air flow from vents in your house, you should check to see if something is blocking it.

This could be a big reason for an AC not blowing cold air.

Checking for Blocked or Clogged Registers

Air circulation depends greatly on minute details.

One such detail is your home’s registers and vents. If they’re clogged, they can prevent the cool air from reaching you.

It leads to uneven temperatures and inefficient system operation.

The Importance of Duct Integrity

Maintain the integrity of your ductwork.

Accumulated dust, dirt, or insects can significantly block the air conditioning system from blowing cool air into your house.

Also, check for duct leaks. You can visually inspect the ductwork for any gaps, disconnections, or tears.

Another method is to use an incense stick and observe if the smoke is drawn into the duct or is blown out.

Repairing these leaks can involve replacing old duct tape or, for more severe damage, replacing sections of ductwork.

Regular inspections by aircon professionals are crucial to identify and remedy duct leaks promptly.

In the long run, it prevents reduced efficiency and increased wear on the air conditioning system.

Recalibrate the Thermostat Settings

Thermostat Settings

I’ve seen many times that merely checking the temperature setting on your thermostat can save you the trouble.

Calibrating Your Thermostat

Your thermostat should be regularly recalibrated to work.

If there’s a difference of more than 1 to 3 degrees between the readings on the thermostat and a thermometer near it, it’s time for calibration.

The calibration process will vary depending on the type of thermostat you have. Here are the steps for each type:

  1. Programmable or smart thermostats: Refer to the manual and use the arrow keys to adjust temperatures in calibration mode.
  2. Mechanical thermostats: Rotate the calibration screw on the coil inside.
  3. Mercury switch thermostats: Level the thermostat if necessary. It’s advisable to calibrate your thermostat annually or as issues arise.

When to Upgrade Your Thermostat

In some instances, upgrading might be the solution if recalibrating your thermostat doesn’t rectify the problem.

Smart thermostats offer better control over your air conditioning system. It has features like Wi-Fi connectivity and the ability to control your unit using a smartphone.

But don’t rush to buy a smart thermostat yet. Consider these factors.

Check for compatibility with your central AC system, compare prices, and consider installation requirements and connectivity.

Choosing the suitable model for your needs can help reduce energy waste and improve the consistency of your home cooling.

AC Freezing Up Still?

Thawing Out Frozen AC

Despite covering all bases, unexpected issues may arise, such as your AC system freezing up. This can happen due to:

  • Low refrigerant levels
  • Insufficient airflow over the evaporator coils
  • Clogged air filters
  • Defective components
  • Blocked air ducts

Fret not, precious! I’ve got you covered.

To thaw a frozen air conditioner, turn off the system and let the ice melt completely.

Do not operate the unit further to avoid straining the compressor and causing potential damage.

To prevent future freeze-ups:

  1. change your filters regularly,
  2. use the correct thermostat and fan settings and
  3. avoid running the AC on cold nights.

If your aircond freezes due to issues like a clogged condensate drain line, a bad compressor, or faulty wiring, it’s time to call the professionals.

Size Matters: Is Your AC Adequately Sized?

Selecting an appropriately sized air conditioner is vital to achieving maximum efficiency.

An undersized air conditioner will struggle to cool your home. At the same time, an oversized one will cool your home too quickly, not allowing enough time for the system to remove humidity, leaving you with a cold but clammy feeling.

To calculate the correct AC size for your home, consider the following factors:

  • Square footage
  • Ceiling height
  • Climate
  • Insulation
  • Sun exposure
  • Heat-producing appliances

If your system frequently cycles, struggles to maintain a comfortable temperature or shows signs of wear, it may be time to consult an aircond expert about sizing.

Regular Servicing

Finally, do not overlook the significance of routine aircond servicing.

A twice-a-year aircond service can maintain maximum efficiency, which can degrade by up to 5% each year without it.

Regular maintenance can help extend the lifespan of your air conditioner by catching potential problems.

Especially before they evolve into expensive repairs. In fact, annual check-ups can prevent almost 50% of AC repairs.

Plus, many air conditioner warranties require regular maintenance to stay valid.

So, do yourself and your AC unit a favor by scheduling regular maintenance.


From checking if your AC unit is running to maintaining its components and ensuring regular servicing, we’ve covered a lot of ground in this blog post.

Remember, a well-maintained AC unit is the key to a cool, comfortable home.

So, follow these troubleshooting tips and keep your AC running efficiently. After all, nothing beats the comfort of a cool, refreshing home on a hot summer day!

Frequently Asked Questions

Why is my AC running but not cooling?

Your air conditioner may be running but not cooling due to issues with the thermostat, compressor, evaporator coils, or a clogged condenser coil, preventing it from working correctly. Make sure to address these potential problems to restore efficient cooling.

How do you fix an AC that is not cold?

To fix an AC that is not cold, check the thermostat fan setting first and ensure it’s set to the correct mode. Then, replace the air filter and inspect the outside unit to ensure everything works properly. Finally, check the thermostat and ensure electricity goes to your AC.

How often should I change my AC filters?

You should change your AC filters at least once every three months, but you may need to do it more often if you have pets or individuals with respiratory conditions in your home.

How can I tell if my AC unit is running?

You can tell if your AC unit is running by checking for operational signs like the humming sound of the compressor or the fan spinning. If these signs are absent or if you hear unusual noises, it could indicate a mechanical issue.

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