It’s that time of the year again: warm summer weather is back! That means it’s also the time when most homeowners crank on their air conditioning systems.
But what do you do when you turn on your AC to find out it’s not cooling your home as it should?
If your AC is struggling to cool down your home and not cooling below 80 degrees, check out this guide.
15 Reasons Your AC Is Not Cooling Your Home
Follow our guide below to learn a few reasons why your AC is not cooling your home well enough or properly and what you can do about it.
1. Improper Thermostat Settings
If you find that your AC isn’t cooling your home to your desired temperature, the first step is always to check your thermostat. It may seem silly, but it’s possible that your thermostat is set incorrectly.
Solution: Ensure that your thermostat is not set to “OFF” and that the fan is set to “AUTO”, not “ON”. The “ON” setting runs the fan and circulates the air in your home, but the air won’t be cooled unless your AC system is running. If your thermostat is set correctly, try lowering the temperature a few more degrees to see if that makes your AC turn on or blow cold air.
2. Blank Thermostat
If the thermostat isn’t working well or at all, it’s possible that the batteries are dead or there’s an electrical issue. If your thermostat can’t properly communicate to your AC system, then your AC system won’t know when to turn on.
Solution: If your thermostat’s display is blank or fading and not as responsive as it normally is, try replacing the batteries. If replacing the batteries doesn’t help, you’ll need to contact an electrician or HVAC technician to diagnose the issue.
3. Closed or Blocked Air Vents
If your air vents are closed or blocked, then the cold air can’t make its way into your rooms to cool them down, making it hard for your AC system to cool down your house.
Solution: Ensure that your air vents are open, unobstructed, and blowing cold air. Your AC system also has return air vents that suck the hot air out of your home. You’ll want to make sure these are also free of obstructions and not blocked as well.
4. No Power
It’s possible that there’s no power to your AC system or the outdoor condenser unit. Your condenser unit is responsible for producing cold air and releasing hot air, so if it’s not running then your AC won’t cool down your home.
Solution: Turn on your AC system at the thermostat and check outside to see if the fan in your condenser unit is running. If the fan isn’t running, turn off your AC system and check to see if your breakers tripped. If the breakers weren’t tripped, check the shut-off switch or if the condenser unit is unplugged. If none of these solutions fix your problem, you’ll want to call a local HVAC company to diagnose the problem.
note: The shutoff switch is usually located in a metal box near your condenser unit. If someone recently worked on your AC unit, they may have accidentally left the switch in the “OFF” position.
5. Clogged Air Filters
When is the last time you changed your AC’s air filters? If it’s been a while, turn off your AC system and check to see if the filters are dirty or completely clogged.
A clogged air filter prevents air from entering your AC system, making it work harder to cool your home. You should regularly check and change your air filters to prevent this from happening.
Solution: Replace your air filters and if it’s been a while since you’ve done this, you’ll want to vacuum off the excess dust and debris that collected on your vents as well, otherwise the filters will quickly clog again.
6. Blocked Condenser
One part of your AC that plays an important role in keeping your home at its coolest is the condenser. Your condenser unit is located outside and is responsible for collecting the hot air from inside your home and releasing it outside.
A blocked condenser prevents your AC system from releasing the hot air from inside your home in an efficient manner, causing the hot air to build up and recycle through your AC system.
Solution: Check to make sure the area surrounding your condenser unit is clean of any nearby debris, shrubs, bushes, leaves, plant overgrowth, or weeds.
If these simple solutions don’t seem to be doing the trick, you may have a more serious issue.
7. Dirty Coils
A dirty condenser or evaporator coil, much like a blocked condenser, will prevent your condenser unit from releasing hot air efficiently.
If you had to remove a lot of debris in our previous step, chances are your coils are covered in a layer of dirt.
Solution: Turn off your AC system and try gently rinsing the outside condenser unit with a hose and then run the AC for another few hours to see if that resolves the problem.
8. AC Blowing Warm Air
Before resorting to these next steps, check to make sure the easily fixed issues listed above aren’t the cause of your problem.
Feel the air coming from your supply vents. Is it hot or warmer than normal? If your home isn’t cooling because your AC is blowing warm air, it’s a sign that something isn’t working as it should be.
Double check that the above problems such as an incorrectly set or blank thermostat, clogged air filters, or a blocked or dirty condenser are not your issues.
Solution: If none of the above solutions fixed your problem, then a part in your AC system may be failing. It’s best to call a local HVAC company to assess and fix your AC.
9. Air Duct Leaks
Your air conditioning system relies on a ductwork system to deliver air to different areas of your home. Holes or tears in the air ducts allow the cold air your AC system products to leak out and escape before it reaches the intended supply vents.
If your air duct has leaks, you might notice that the airflow coming from your vents is weak and the air doesn’t feel as cold as it should.
Solution: You can try patching small holes or tears yourself if your ductwork is easily accessible and you know where the leaks are, but it’s best to have a professional inspect, clean, and seal your ductwork.
10. Refrigerant Leak
Refrigerant is the liquid cooling agent in your evaporator coil that cools and dehumidifies the air. Refrigerant is not lost or used as part of a properly functioning AC system, so if your AC system is low on refrigerant, you most likely have a refrigerant leak.
Some obvious, sure signs of a refrigerant leak include:
- Ice on the refrigerant lines
- Frozen evaporator coil
- Tiny bubbles in the evaporator coils or on the refrigerant line
- Hissing noise coming from refrigerant lines
Some signs that you may notice over time signs of a refrigerant leak include:
- Higher electric bills
- AC takes longer to cool your home
- AC not blowing air as cold as it used to
- Increased humidity
- AC leaking water
- Decreased airflow
Solution: If you notice any of these signs, contact an HVAC technician to fix your problem. Refrigerant leaks are dangerous not only to your AC unit but also to your health.
11. Compressor Failure
Your AC’s compressor pressurizes the refrigerant in your AC system, transforming it from gas to liquid to gas again in a continuous cycle. This is an important part of the cooling process in an AC system that allows the heat to be removed from the air and released outside.
If your compressor starts to fail, the refrigerant will not be able to properly remove the heat from the air, making it harder for your AC system to produce cool air.
Solution: Compressor failure can be an expensive repair, but it can also cause other parts in your AC system to wear down more quickly as well. So it’s important to have an HVAC technician diagnose and repair your system immediately if you suspect the compressor is failing.
12. Fan Motor Failure
Your condenser unit uses a fan to release hot air. If the fan isn’t spinning, then the hot air doesn’t dissipate outside.
A fan motor powers the condenser units fan. If the fan isn’t running continuously or at all, then there’s probably a problem with the fan motor.
Solution: You can try to test and replace the fan motor yourself, but you’ll probably want to call an HVAC technician to diagnose and fix this issue as well.
13. High Outdoor Temperatures
Outside temperatures above 95 degrees can make it nearly impossible for an air conditioner to keep any home below 70 degrees inside.
Solution: If your air conditioner is not cooling your house below 80 degrees and none of the above solutions fixed your problem, try some other steps to keep your home cool, such as:
- Closing windows and shutters
- Installing blinds or blackout shades
- Using ceiling fans
- Being strategic with landscaping by planting tall, shaded trees and utilizing vines on the side of your home (note: be sure not to block your condenser unit)
14. Old, Inefficient AC
If your AC system is older than 10 years old and not meeting your home’s cooling needs, you may need to replace it.
Over time the parts in your AC system wear down and don’t perform as efficiently as they used to. Central AC systems have an average life expectancy of 15 to 20 years and that’s only if you care for it properly and perform routine maintenance on it regularly.
Solution: Contact a local HVAC company to come out and give you a quote on a new AC system. Newer systems are often much more efficient, so you could save up to 20% on monthly cooling costs.
15. Undersized Air Conditioner
Another common cause of inadequate cooling may be that your AC unit is too small for your home. An undersized air conditioner will run continuously but never cool down your home.
If your AC system is fairly new and none of the other problems listed here are causing your AC not to cool down your home, this is probably your issue.
Solution: Check with your local AC expert to evaluate the size of your home and ensure that the unit is the right fit for your needs.
note: If your AC system was recently installed and isn’t cooling enough, but is properly sized, then it may have been installed incorrectly. You’ll want to have the company come back out to inspect the system or contact another HVAC company for a second opinion.