5 Common Air Conditioning Problems and How To Fix Them

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It’s 100 degrees outside, you’ve just cut the grass for the 2nd time this week, and all you want to do is come in to enjoy the nice, cool air from your air conditioner while you relax a little. Unfortunately, you walk in from the sweltering heat outdoors to be greeted by a stale, swelter inside your home too.

A working air conditioner is truly one of life’s great joys, so when it isn’t working, it can be devastating. Unlike a faucet or other simpler machine, an air conditioning system is intricate and can be intimidating to repair.

While some repairs should only be handled by a professional, there are some quick and easy fixes for common air conditioning problems that the average homeowner could try before calling in an HVAC repair specialist.

common ac problems

Safety First

hvac tech checking thermostat

It’s important to remember the A/C unit is a giant working machine with many working parts and electricity involved. If you ever feel uncomfortable diagnosing and repairing a unit, you should call in a professional. In the long run, it will save you time, money, stress, and potentially save you from injury.

There are few repairs that should only be performed by a local HVAC company. These include compressor cleaning, electrical malfunctions, some coil cleaning, and overall general maintenance.

Common AC Problems

While it’s easy to jump to the scariest conclusion when you first feel that warm air, stop, take a breath, and try these fixes before you resign yourself to a summer of sticking your head in the refrigerator for a blast of cool air. Of course, if it proves too much, you can always call an air conditioning repair expert to diagnose the problem.

Reduced Air Flow

The air conditioning unit’s effectiveness depends heavily on air flow, so if air flow is obstructed in any way, then it can lead to reduced performance.

How to Fix Reduced Air Flow

Check your filters!

check ac filter

Easily, the number one cause of reduced air flow, and thus warm air, in an air conditioning unit is dirty filters. Generally, it’s recommended that you change your filters monthly. So if you have to think about when the last time you changed your filters was, then it’s time to change your filters!

This fix can easily be done without the help of professionals. Just be sure to check the size of your filter before you go to the hardware store.

Sometimes there is more than one filter so be sure to check your unit and all of the intake vents around the house for filters. Replace all of them at the same time so you ensure the best air flow possible and get on a schedule for replacing them.

Clean your ducts

dusty air duct

Ducts are the tubes and airways that the air flows through to get to the various vents in the house. While the intake filters catch the vast majority of dust, pet hair, and dirt, sometimes debris gets through. If you do not regularly clean your ducts, then that debris can build up over time (with the help of static electricity) and cause a blockage in the ducts that reduces air flow. If air isn’t flowing, then air isn’t cooling.

Generally, it’s a good idea to clean your air ducts once a year by a professional to ensure all of the dust and dirt particles throughout the entire system can be addressed rather than just what you can reach.

Check your ducts for leaks

Sometimes the ducts have no debris in them, but time and age have worn a small hole in the ductwork causing a small air leak. Occasionally, even small animals get into the ducts and cause holes or other damage.  

Air leaks reduce air pressure and reduce the amount of cool air circulating through the system. If you have uneven air pressure throughout the vents in your home, then a leaking duct may be to blame. These are complicated fixes, so they almost always require the service of an AC repair specialist.

It’s also a good idea to have your local HVAC repairman check for leaks while you’re getting your ducts cleaned. This way, you can avoid paying for multiple trips, and you’ll be able to stay up to date on maintenance with yearly inspections.

Learn More: Air conditioner tips to keep your costs down.

Air Conditioner Making Strange Noises

There are many reasons your air conditioner could be making strange noises. These range from just needing a clean, to being a very serious problem.

Check out our full article here on Noises That Your Air Conditioner Shouldn’t Make – And What To Do About It.

Refrigerant Leaks

The A/C works by running coolant through coils that cools the warm air flowing around the coils. The coolant in the system can sometimes leak causing inconsistent cooling and fluctuating temperatures, usually when you need it most. A tell-tale sign of a refrigerant leak is inconsistent cooling- if it is particularly warm outside then the air that is trying to be cooled is warmer, so it has to work extra hard to cool that air. If there is a refrigerant leak, then there might not be enough coolant in the system to cool that extra hot air effectively, leaving you with lukewarm air and a hot, humid home.

The tricky thing about a coolant leak is that, sometimes, the a/c works beautifully, lulling you into a false sense of security, but don’t be fooled! If you have lukewarm air once, it will happen again. It’s best to get that leak taken asap.

How To Fix Refrigerant Leaks

It’s best to call a professional if you suspect a leak because the coils are located inside the unit, so if there is a small hole or corroded fitting, then a professional can easily diagnose and fix the unit.

Please note that while it might be tempting to just put more refrigerant into the unit to make it through the worst of the summer without spending money on a professional fix, this is only a bandaid. The A/C unit is a closed system so if you’re having to replace the refrigerant, it means there is a leak somewhere which should not be ignored or it may cause even more damage.

Dirty Coils

Sometimes, there is no leak in the refrigerant, but instead the coils are so dirty that the coolant can’t actually reach the air to cool it. This happens because of the natural dust and dirt in the air that builds up over time. If your coils create condensation, then the dirt automatically sticks to the wet coils causing more blockage. Eventually, it builds on itself and creates a coating around the coils and the air can no longer be cooled effectively. This can be another reason your air conditioning is not working properly and blowing out warm air.

How to Clean Dirty A/C Coils

In this case, a thorough cleaning will solve the problem. Unfortunately, the coils are located inside the unit, so while cleaning them is not complicated, getting to them is. It’s usually best to call in a professional for this fix. Luckily, while the repairman is there, they can ensure there are no leaks in the coils and make sure your system is working in tip-top shape.

Read More: How a UV Light in your HVAC System can keep your family healthy.

Blown Capacitor

If your indoor unit is working, but you notice your outdoor unit isn’t working then your problem may be electrical. Sometimes even the fan on the outdoor unit is working, deceiving you into thinking the outdoor unit is working. But if you don’t hear the tell-tale hum of the whole air conditioning unit working, then you might have a blown capacitor.

The capacitor stores energy to start your air conditioning unit because a regular 120-volt power supply is not enough. The fan takes less energy to run than the entire air conditioning unit so it’s possible your fan is running but your unit is not. Listen for the hum. If your outdoor air unit doesn’t start, then it’s likely an electrical issue and the capacitor needs to be replaced.

How to fix a blown capacitor

If you suspect an electrical problem with your air conditioning unit, then it is always best to call a professional.


How do I know when to call a professional?

Air conditioning units are built to last through many years of extended use, but they are complicated machines that can sometimes malfunction due to weather or deterioration. If you find that something within the unit itself is not working correctly (refrigerant leaks, the sound is off, or it doesn’t turn on), then you’ll want expert help to handle it safely.

It is best to first check air filters and vents for obvious obstructions so that you can try to solve the problem yourself. If you don’t notice a difference, call for repairs.

It is too expensive, is there an easy fix instead?

Unfortunately, your air conditioner is something you don’t want to take a chance on. It’s a complicated system composed of an air flow system, an electrical system, and a refrigerant system. If you suspect a problem with anything other than an air flow problem, it is best to call a professional to properly diagnose the problem. Ultimately, it’s more efficient to fix one problem with one system within the unit, than let the whole unit go bad because you waited too long to call a professional.

What is BTU?

You may have heard the term BTU thrown around when reading up about air conditioners. But what exactly is it? Well, read our guide on What is BTU.

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Aaron is the founder of and Essential Home and Garden. With over 15 years of hands-on experience in home ownership, lawn care, and gardening, Aaron is a seasoned expert in areas like lawn care, DIY, HVAC, and pest control.

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