How to Fix Air Conditioner Not Cooling

Having an HVAC system that blows warm air instead of cold air isn’t something to smile about as a homeowner. I mean, the summer’s uncomfortable experience can take a toll on you if the air conditioning system isn’t efficient.

A refrigerant leak and a dirty filter are the most common causes of an aircon not properly cooling. So, how can you improve your indoor air quality as a homeowner? If you have no idea how to do it, this article will help you. So stick around till the end.

Why Is My Air Conditioner Not Blowing Cold Air?

1. Dirt or Debris has Clogged AC Air Filter

When dirt or debris clogs the air filter, they restrict airflow through your ac. As a result, the air conditioning system won’t cool the air inside your house effectively. Also, a clogged air filter can interfere with the indoor evaporator coils or the outdoor condenser unit in ac units. 

2. The Refrigerant may be Low or Leaking 

There are two reasons your air conditioner may have a refrigerant leak; leaks in the compressor or undercharged system when an HVAC technician was installing the ac.

3. Frozen or Dirty Coils

Often, coils get dirty because they remain humid over time, and this provides a good atmosphere for mold or mildew to grow; this can seriously affect your air conditioners in terms of performance. Moreover, coils stop working the way they are supposed to when they freeze or if the refrigerant is too low in your ac system.

4. There is Leaking Air

If pests like rats, squirrels, and other critters invade the attic, they can damage the ductwork, which leads to leaks from your ac. Moreover, plumbers or home ductwork technicians can also damage the ductwork by mistake.

5. Compressor isn’t Running

The air conditioner’s compressor is its heart. It circulates the refrigerant between the two units, indoor and outdoor. When something damages the compressor, the entire ac system won’t cool your in-house air effectively. 

6. Faulty Exterior Fan Motor

If the fan gets faulty, the AC’s compressor will likely overheat. The best solution for a faulty exterior fan motor is to contact an HVAC pro for troubleshooting or replacement.

7. Thermostat has Issues

If the thermostat has issues, it can result in your ac underperforming. Most of the time, it’s because the thermostat settings aren’t accurate. For example, remember to set your thermostat to cool instead of heat.

8. Dirty or Blocked Registers

Your AC’s registers might get dirty if not cleaned up for a while, just like air filters, especially if you forget to clear up the registers regularly. If the registers become dirty, the quality of airflow will reduce. In addition, some people block registers on purpose since they don’t use a particular room.

So if the registers are dirty or something blocks them, your aircon will have to work harder. And as a result of that, your energy bills surge while the aircon is not blowing cold air in your home. 

9. Excess Sun Heat

Escaping the heat from the sun is the main reason why we invest in air conditioners. However, if the sun’s heat comes into direct contact with the air conditioner’s thermostat, the excess heat will cause the ac system to overdrive; this results in the aircon having problems. On unusual hot days, I advise you to draw your shades to reduce the heat load in your home.

10. Poor Air Conditioner Maintenance

Poor maintenance of the air conditioner is a common reason they become unable to produce cold air. You may maintain the air conditioner’s different parts clean. But still, you have to look for a qualified HVAC company to check your air conditioner system thoroughly.

I recommend you do an aircon tune-up at least twice a year, spring and fall. During the tune-up, the air conditioner technician will inspect the parts you, as a homeowner, can’t reach easily. Also, the HVAC pro will identify potential problems and tackle them; this prevents expensive repairs.

11. Damaged Heat Pump System

If your outdoor air conditioner unit has a heat pump, pests and debris can damage it. Or, it can deteriorate over time, or issues like clogs, leaks, compressor malfunctions, or frozen coils may affect its performance. A damaged heat pump system will have to render your aircon useless since it won’t effectively cool your house.

12. Tripped Circuit Breaker

If your air conditioning unit doesn’t turn on at all, you will need to check the electrical panel to find out if something has tripped the breaker. If that’s the case, then you can reset it.

13. Blown Fuse

An air conditioner may not turn on if a fuse has blown up. You need to verify if the air conditioner is plugged into the power supply or check for a fault on the electrical panel. If nothing changes, look for an HVAC pro because the issue may need someone experienced.

14. Reduced Airflow Due to Blocked Vents

Blocked supply vents often cause your air conditioner not to blow enough cold air. Check the vents for dust or dirt buildup as they may prevent airflow. Furniture, closed dampers, or toys can also contribute to the problem. Move furniture away from the registers and look for obstructions in the ducts.

How to Fix Air Conditioner Not Cooling

1. Check the Thermostat Settings and Reset Them If Need Be

Turn off the air conditioner unit at the thermostat – look for the shutoff and remember to turn the thermostat to the “off” position. Find the circuit breaker box – locate where the circuit breaker is. It’s usually in the basement area. Otherwise, look for it in the closets or crawl spaces until you find it.

After you find it, flip the AC’s circuit breaker to the “off” position. Wait 30 seconds before flipping the air conditioner circuit breaker back to the “on” position.

Turn the air conditioner thermostat back on – after resetting the thermostat, you need to test it. Verify that your AC’s thermostat is in the “off” position. Then carefully turn it to “on.”

After that, set your desired temperature. Sit back and wait for your air conditioner system to release cool air.

2. Replace the Ac’s Dirty Air Filter

  • Loosen the fasteners carrying the grille front to the vent. And gently remove its casing, set it aside. The air conditioner system’s air filter is directly behind the casing.
  • Reach and pull it out.
  • Set aside the filter and asses it. A dirty air filter usually has a greyish-brown color if it’s old. But if it’s still white, the filter is okay. 
  • Grab a new air filter if the other filter is dirty.
  • Examine the air filter’s arrow pattern. Its direction is important because it ensures the airflow occurs appropriately. The air filter arrows should not point at you or out. If they do, they won’t go on usually.
  • After finding the air filter arrows, make them face the wall.
  • Put back the air filter to the duct opening, easing the air filter’s bottom part in and the top afterward.
  • Double-check to ensure the arrows point towards the duct.
  • Give the air filter a gentle pat; this ensures that it fits into the opening snugly.
  • Put the casing back.
  • Tighten the fastener

3. Clear Up the Air Conditioner’s Condensation Line

The condensation drain hose directs water to the floor drain or outside your home. But it depends on the ac system. Cleaning condensate drain line: 

  • Turn off the air conditioner system.
  • Remove the pipe’s cap.
  • Check for any debris that has stuck in the drain.
  • Remove the debris and test for proper drainage.
  • Pour in vinegar.
  • Change the drain cap.
  • Discard the drain cap.

If there is a clog up in the drain line where it’s possible to reach physically, you can remove it by suctioning the end part of the drain line. Then, using a hose on a wet or dry vacuum, hold your hands on the opening to create enough grip between the two vacuum hoses.

After clearing algae or mold clog, drip some cups of vinegar into the AC’s condensation pan beneath the evaporator coils found inside the blower unit. 

4. Diagnose Duct Malfunctions

In a central air conditioning system, its primary blower forces out cold air via the ducting towards individual rooms. When the duct located between a room register and the blower breaks, the cold air blows out before reaching the room’s register. If the cool air blows from some registers and not all of them, then the registers’ ducting might be faulty.

5. Clear Out Areas Around the Compressor 

If debris and dry leaves have accumulated near the ac compressor, it will be challenging to draw in enough air. To find out, check the compressor unit fitted behind or the sides of the house where it’s not easy to notice.

6. Clean Dirty Coils

If your air conditioning system is working but not blowing cool air, a dirty coil is a potential culprit. The typical AC has two coils; the external coil housed in the outdoor compressor and the evaporator coil near the inhouse blower unit.

Cold air output goes down if either the condenser or evaporator coil becomes dirty due to debris or mold. Cleaning the set of coils involves discarding the metal enclosures protecting them. Coil cleaning step by step:

  • Cut off the exterior and interior system from the power supply at its breaker panel. Each system sits on separate breakers.
  • Follow the air conditioning unit manufacturer’s instructions for discarding the exterior compressor’s cage or the panels that protect the evaporator coils.

To clean the interior/evaporator coil, spray the coils using a no-rinse coil cleaner, for example, Nu-Calgon Evap Foam. The evaporator coil is U-shaped or looks like a steel tube.

The no-rinse cleaner produces foam on the evaporator coil that absorbs grime and dirt before turning to a liquid and running into the condensation pan, which later moves to a condensation drain hose.

To clean the exterior coil, spray it, and the metal fins with a suitable condenser cleaner like Nu Blast from Nu Calgon. The Nu Blast cleaner requires rinsing using the hose.

7. Replace Your Undersized or Old Air Conditioner System

A well-sized air conditioning unit turns on and off at particular times to control your home’s temperature. But undersized air conditioning units struggle to cool the room well enough.

Hence the AC’s on and off life cycle won’t be healthy; this will force you to replace the air conditioner unless you can handle expensive repairs.

Elsewhere, naturally, you have to replace an AC that has served you for 10-15 years due to unavailable or obsolete mechanical parts. For example, you can’t find the spare parts of an ac used in the early 80s. That’s a fact!

When to Call a Licensed Hvac Technician

Have you tried all those DIY steps, and nothing has borne fruits? If yes, it’s time to call an HVAC pro. The following are other common issues that a licensed HVAC technician can solve adequately.

Blocked Condenser Unit

A clogged external coil can’t interfere with an air conditioner running, but it will affect the cooling systems. Moreover, the external coil performs the drawing heat energy role and directs it to the outside air conditioning unit.

Dirt, airborne particles, or grass can lead to a clogged external coil. Allow an HVAC professional to handle such issues, especially if the airborne particle have invaded the external coil.

Leaking Refrigerant

A refrigerant plays a part in the cooling process. It cools warm air before transporting it to the indoor air handler unit’s indoor portion. If the ac unit starts leaking refrigerant in the indoor or outdoor systems, you need an HVAC professional to refill and check refrigerant lines.

Air Conditioner Not Cooling FAQ’s

Should I Turn My Ac Off If It’s Not Cooling?

If your ac unit isn’t cooling, you can do the following; this is very important; turn it off and look for an HVAC company. HVAC technicians always advise homeowners to turn off the ac if it isn’t cooling correctly.

Ac Running but Not Cooling

Suppose the air conditioner is running normally and isn’t lowering temperatures inside. The issue could be a clogged external coil. When working, usually, a fan draws air to the outdoor unit via the condenser coil to pull heat energy from your home.

What to Do If Central Ac Is Not Cooling

  • Clean the filter. First, cut off your HVAC unit from the power supply.
  • Clean the ac unit’s interior. Next, clean the evaporator, condenser, coil, and filters.
  • Check your air conditioning unit’s electrical wiring. About 85 percent of HVAC repairs happen due to electrical problems.
  • Check your ductwork.
  • Check if there are refrigerant leaks.

Air Conditioner Running but not Lowering Temperature

Suppose the air conditioner is running normally and isn’t lowering temperatures inside. The issue could be a clogged external coil. When working, usually, a fan draws air to the outdoor unit via the condenser coil to pull heat energy from your home.

What to Check If Ac Is Not Cooling

A dirty air filter blocks airflow and reduces your home’s cooling effect. In extreme cases, it can cause your ac system to shut down totally. For example, suppose your thermostat settings are okay, but there’s no cool air in your house; look for the AC’s air filter. Turn off the system, then remove and inspect the filter.

Ac Constantly Running but Not Cooling

If your aircon isn’t cooling while the ac unit system is on, there may be a blocked or clogged coil. Unfortunately, different debris types can infiltrate the ac equipment, including dirt, grass, and other materials. The clogging can cause a malfunction.

Ac Not Blowing Out Cold Air

1) Make sure the condenser fan setting is “auto” instead of “on.” If it’s “on,” the ac system will blow air that hasn’t cooled. 2) Check the air filter. And if the air from the supply vents is not cool or weak, examine if the air filter has some dirt and replace it if need be.

Compressor Running but Not Cooling

If your air conditioning system’s compressor is working, but there’s no cooling, you can resolve this by checking the inner temperature of the refrigerator. If you find that the refrigerator’s internal temperature is okay, the evaporator coils might have frosted over.

Ac Fan on but Not Cooling

When the air conditioning system’s compressor isn’t functioning, but the AC’s fan is operating, the problem might be the outer unit that houses the compressor; the power may not be reaching the external unit. Well, the fans keep running since the central unit isn’t faulty. Other causes might be the indoor, and outdoor ac units aren’t matching, a defective thermostat, or your air conditioning unit is too old.

Ac Unit Running but Not Blowing Air

If the aircon unit is working, but no air is passing through the vents, the chances are that a fan capacitor is dead. A fan capacitor helps your unit’s internal and external fan motors blow, and the compressor runs.

Outside Ac Unit Fan Running but Not Cooling

A clogged or jammed condenser coil can cause your air conditioner to run but not drop temperatures inside. The external fan pulls air towards the outside unit via the condenser coil to take out heat energy from your house while it’s functioning correctly.

Window Ac Not Cooling Enough

Inadequate airflow is a common cause of most window aircon systems blowing less cooled air. If the aircon’s air filter is clogged or dirty, air passing through the evaporator coils will be minor, making them too cold. Moreover, ice or frost will build upon them, hindering airflow.

Air Conditioner won’t Cool Below 75

A clogged filter is a common culprit when it comes to performance issues. You have to clear up the condenser of an aircon on all sides for it to exhaust heat. If any dirt or material blocks the condenser, the aircon won’t cool down the refrigerant low enough.

Is your AC not Cooling?

One of the ways of fixing air conditioners not properly cooling is by cleaning or replacing air filters. Elsewhere, the summer’s harsh conditions will eat you up if your aircon is inefficient. So it would help if you cleaned or replaced your system’s air filters and the condensation line to fix your HVAC system, making it more efficient. Finally, how many years do you think your aircon system can run efficiently and effectively?