Air Conditioning Not Cooling

AC Not Cooling Your Home? 13 Common Reasons Why?

About 87% of the population of the US have Air Conditioners in their homes. And that is the reason people spend a lot of money on their efficient home air conditioning.

But, is your air conditioner not cooling your home anymore? Don’t sweat it, this could actually be a quick fix. Keep reading to learn more about the most common HVAC issues and how to solve them. Or, jump straight to the section you’d like to learn more about.

13 Reasons Why the Air Conditioner Not Cooling House

AC not cooling? Nobody wants to deal with that during a summer heat spell. And if your air conditioner is not cooling properly, or if your AC is running but not cooling, there are some common causes you might be able to figure out yourself.

1. Dirty Air Filter

It doesn’t matter what kind of air conditioner system you have, if you have a clogged filter, this limits the airflow. When this happens, the efficiency of your AC is reduced, and there is less of a chance that the system is cooling your home well.

If you haven’t cleaned your filter in your portable or window AC unit, do that and also make sure you check it periodically. You should change your central AC filters at least once a month, especially if you’re running your system a lot and or if you have pets.

When your AC blows hot air, this may also be a sign of a dirty air filter, which can cause flow issues.

ac air filters - ac not cooling house


2. Incorrect Thermostat Setting

If your central air conditioner is blowing hot air when it should be sending out refreshing cool air, you may have simply set the thermostat to “heat” instead of “cool”. 

Another thermostat issue you might run into is the thermostat’s temperature reading. If the temperature of your AC thermostat seems off, you should make sure that your thermostat isn’t being exposed to any direct sunlight. Direct sunlight may resist the blowing of cold air.

incorrect thermostat settings

3. Low Refrigerant

When your air conditioner running but not lowering the temperature, it could be because you are low on refrigerant. However, you’ll want to check for any leaks before you add any more refrigerant. Often, problems with leaks will keep happening and they can be harmful to the environment.


4. Refrigerant Leak

A leaking air conditioner spells problems for a cool, comfortable home. If your home isn’t cooling down, check the refrigerant pressure. If the refrigerant has leaked, then the low-pressure safety could have been switched.

It’s important to seek a professional right away if you find a leak because HVAC refrigerants can cause health problems.

If the refrigerant isn’t leaking or low but you see puddles or moisture, this could be because the process of air conditioning makes condensation, which is usually drained. However, sometimes. the pipes can be blocked or leak or the condensate pump just stops working.

If this happens, try to clean your condensation drain pipe and clean your system of algae with bleach. You’ll also want to check the electrical connection to your condensate pump.

refrigerant leak

5. Clogged A/C Unit

Your outdoor compressor for your central air conditioning needs to have decent airflow to properly work. So, make sure there are at least two to three feet of space between your compressor and any structures or plants. There should also be about five feet of space between the top of your outdoor AC unit and any trees above it.

If you find that your AC comes on and off repeatedly, then there is a signaling problem. Typically your condenser unit is blocked or dirty or your evaporator is dirty. You’ll want to check both for obstructions and give your unit a good cleaning to clear any debris.

clogged ac unit

6. Warm Window

If you have a window AC unit and it gets direct sunlight in the heat of the day, it’s going to be a lot harder to clean your home. If you are able, try to move your AC unit to a less sunny spot.

If you can’t move your AC unit, then you should keep your curtains and shades down during the day so you can block the sunlight so your house won’t heat up. The same is true if you have central AC.

If you have a window AC, be sure to check the seals around your unit to make sure that the hot air from the outside isn’t leaking in and the cold air isn’t seeping out. You might need to reseal your unit with weather stripping.

An air conditioning unit sticking out a window.

7. Leaky Ducts

Duct damage caused by pests, improper installation, and other mishaps can result in leaking air from your AC system. Because ducts distribute conditioned air throughout your home, damaged ductwork reduces the system’s overall efficiency. And an inefficient AC system can mean higher utility bills.

Noise can be another symptom of an issue with your ducts. If you hear a popping or pinging, that could be a loose flap of metal in the ductwork. recommends cleaning out your ducts if there are excessive amounts of dust, evidence of pests, or evidence of mold.

If your outdoor unit is a heat pump, it can get damaged by debris and pests. Or, it can simply deteriorate over time and be subject to issues like frozen coils, leaks, clogs, compressor malfunctions, and other problems. When your heat pump is damaged, cooling your house with your AC won’t be effective.


8. Damaged Heat Pump

If your outdoor unit is a heat pump, it can get damaged by debris and pests. Or, it can simply deteriorate over time and be subject to issues like frozen coils, leaks, clogs, compressor malfunctions, and other problems. When your heat pump is damaged, cooling your house with your AC won’t be effective.

9. Frozen Coil

A central air conditioning system will include an evaporator coil. If you have a frozen evaporator coil, then your AC is working overtime as your house is staying hot. Check for any airflow issues like a dirty filter. Also, check your blower fan and refrigerant level.

In particularly bad frozen coil cases, you might even see ice on the AC unit.

frozen coil ac

10. Tripped Circuit Breaker

If your air conditioner won’t come on at all, check your electrical panel and see if your breaker is tripped. If the breaker is just tripped, you simply need to reset it.

tripped circuit breaker

11. Blown Fuse

Another reason why your AC unit won’t turn on might be due to a blown fuse. You should verify that your unit is plugged in and check the electrical panel.

blown ac fuse

12. Broken Fan

If the fan for your outdoor unit isn’t turning on, then your AC is not cooling. You should press the reset or overload button and try to reset your unit. Or if your unit is turned off, then try to spin your fan blades clockwise.

If the blades can freely spin, you might have a problem with your capacitor and it might need to be replaced.

broken ac fan

13. Bad Compressor

If your compressor isn’t running that could mean that there is a defective start capacitator, burned wire, or just a defective compressor. If it won’t reset, you’ll want to adjust your refrigerant charge, check the capacitor, clean the condenser coil, and replace the compressor.

Common A/C Problems

When to Call a Pro if Your AC is Running but Not Cooling The House

If your AC is running but not cooling the temperature, relax, because this is one of the most common AC problems. The problem is usually easy to diagnose.

Still, if you find “Why is my air conditioner not cooling the house?” or find any cause for concern, remember to immediately call a professional for help.


fischer heating sytem repair firm and company

Contact Fischer Heating and Air`s Licensed AC Repair Professionals at (206) 202-9499 to get instant service for Air/Conditioning/HVAC Repairs. For 40 Years Fischer Heating and Repairs has been earning the trust of their customers and their neighborhoods and is greatly known as one of the top HVAC companies throughout greater Seattle.