Top 18 Common AC Problems and Solutions: The 2024 Homeowners Guide

Top 18 Common AC Problems and Solutions

Your Guide to the Top 18 Common AC Problems and Solutions!

Summer has arrived, and it’s time to turn on your air conditioner.

But what do you do if nothing happens or you experience one of the common ac problems listed below?

Homeowners don’t need to be experts on HVAC systems, but it is helpful to understand what type of knowing problems can occur in keeping you cool.

Knowing what to do and fixing your AC yourself can avoid that service charge from your local HVAC contractor.

If you need to call out an HVAC technician, articulating your problem can go a long way in fixing the issue affordably and quickly.

So without further ado, here are the top 18 most common air conditioner problems.

🙋 NOTE: All of the problems below also pertain to heat pumps during summer.

Residential Central HVAC System

⭐ Air Conditioner Problem No.1 – AC Not Blowing Cold Air

Nothing worse than turning on your air conditioner for the first time after spring and realizing it’s not blowing cold air.

This could be caused by improper thermostat settings, leaking ducts, low refrigerant levels, and dirty or clogged air filters.

⚒️ The Fix!

Start with checking your thermostat settings and see if that fixes it.

The next thing to check is your air filter. If it’s dirty or clogged, it could cause your AC not to blow cold air.

If it’s neither of these, then it’s time to call an HVAC professional.

To learn more about your AC not blowing cold air, check out this article: Why Is My AC Not Blowing Cold Air?

Related Reading: Why Is My Room So Hot Compared to the Rest of the House: 10 Reasons Why!

⭐ No.2 – Thermostat Not Working?

checking thermostat settings

A malfunctioning thermostat is one of the most common problems we come across.

This could be as simple as dead thermostat batteries or a more serious issue such as corrosion or loose wires.

Another problem could be the placement of your thermostat sensor.

You will get improper readings if it’s in direct sunlight during those hot summer days.

⚒️ The Fix!

If your thermostat is battery operated, check those first.

When in doubt, just replace them.

It’s a cheap and simple fix and helps rule that out as an issue.

You can also remove the cover and check for dust and corrosion within the control panel.

If there’s dust build-up, use a soft brush and lightly clean it out.

These are easy to damage, so be careful. If there’s corrosion, it’s time for a replacement.

To check the calibration of your thermostat, get a glass thermometer and place it next to your thermostat.

If, after 15 minutes, there’s a discrepancy of more than one degree, it’s time to recalibrate your thermostat. Also, check the placement.

It should be located in the room you most frequently use and mounted to the wall in a shaded area.

For a more in-depth look at troubleshooting your thermostat, check out the following article: Thermostat Not Working? Read our Quick Fix It Guide!

Related Reading: What Is The Best AC Temperature for Summer

⭐ No. 3 – AC Blowing Hot Air

mother and daughter home on a hot day

If you own an air conditioning system, you probably know it’s not meant to blow warm air.

The last thing you want in summer is to get hotter!

Hot air means you have a dirty filter, have an obstruction in your ducts, have low refrigerant levels, or have a problem with your outdoor unit.

⚒️ The Fix!

Again, check your AC unit filter to ensure you have sufficient airflow.

Also, check the ducts for obstructions or if one has collapsed.

This could be a good time to schedule duct cleaning to improve your indoor air quality.

If it’s a refrigerant problem, it’s time to call in the professionals.

⭐ No.4 – AC Not Turning On

Another annoying problem to have in summer.

This could be a variety of issues, from dirty air filters and incorrect thermostat settings to a problem with your AC unit circuit breaker.

⚒️ The Fix!

If you are working your way down this list and checking these items as you go, there’s a 75% chance you have already fixed this problem.

Also, check that you don’t have a tripped circuit breaker, or your air conditioner tripped out due to a flooded drain line.

If you want to learn more about this issue, then check out: Help! My AC Won’t Turn On. 5 Troubleshooting Steps for a Broken AC.

⭐ No.5 – Dirty Air Filter

changing out a Furnace filter

A dirty air filter is the top cause of common air conditioning problems and the cheapest fix of them all.

A clogged filter restricts air flow and decreases the efficiency of your air conditioning unit.

It can also cause a whole range of problems, as you have read so far. 

The following article can help in understanding issues caused by a dirty air filter: Top 5 HVAC Problems Caused by a Dirty Air Filter

⚒️ The Fix!

Check your air filter and see if it needs replacing.

During peak use, such as summer, you should check your filter every 2 weeks and replace it every two months or as per your manufacturer’s suggestions.

There is more to air filters than you think, so be sure to check out this article: Air Filter Guide. MERV Filter Ratings and What They Mean For Homeowners.

Other related articles:

⭐ No.6 – AC Fan Not Working

Outdoor condensing unit showing air flow

For your air conditioner to work correctly, it has to be able to transfer heat from the inside of your home to the outside.

It does this by shedding that heat from the condenser coil to the outside air via the condenser fan motor. If the fan isn’t working correctly, that heat transfer won’t happen.

At this point, your AC compressor may overheat, or you will trip the safety.

If your compressor fails, it will be an expensive fix. You may even need a new AC.

Check out our article to learn more about your AC fan not working: AC Fan Not Working? The Homeowners Guide to Cool Air

⚒️ The Fix!

If your fan fails to switch on, it’s likely a wiring issue or loose electrical connections or components within your air conditioner.

You can remove the outer casing of your outdoor unit and visually inspect it to see if anything doesn’t look right.

NOTE! Ensure the power is off before removing the cover before the inspection.

Electrical problems can be tough to diagnose, so it’s best to call an HVAC expert at this point.

If you want to DIY your own solution to fix your condenser fan motor, check out this article: The Ultimate Guide to DIY Air Conditioner Repair.

⭐ No. 7 – Frozen Evaporator Coil

frozen evaporator coil

Another cause of your AC not keeping your home cool is a frozen evaporator coil.

This can is a common problem when your AC unit is not receiving sufficient airflow over the evaporator coil.

This could be from various existing problems, such as dirty air filters, a dirty evaporator coil to insufficient refrigerant in your air conditioner.

⚒️ The Fix!

A frozen AC can cause a range of damage so ensure you inspect your evaporator coil inside the indoor air handler first. You must let your evaporator coil thaw out before using it again.

This can take up to 24 hours so read this handy guide on what to do when you have a frozen evaporator coil: How to Deal with Ice Build-up on Your AC Unit.

⭐ No. 8 – Water Leaking From AC System

Condensate Drain Line

Water leaking from your AC is another of those common air conditioner problems.

As well as cooling the air, your AC removes moisture as part of the process.

If you have water leaks inside or out, this is a warning that maintenance is overdue!

The major reason for water leaks in your AC is that you have clogged drains.

You may also have an issue with the condensate pump.

⚒️ The Fix!

Ensure your condensate drain line is not blocked and your condensate pump works to reduce water leakage inside.

Regular maintenance generally keeps this problem in check. Water buildup in your air conditioner can also cause dirty sock syndrome.

Be sure to read the following article to fix this issue: Dirty Sock Syndrome: DIY Fix It Guide.

If it’s the outside unit, then it’s definitely time to call an HVAC technician.

This can be from issues such as improper installation, bad air filters, broken condensate pan etc. Air conditioners may not drain properly if not mounted level.

If you want to learn more about leaking air conditioners, check out: AC Leaking Water? Here’s Why and How to Fix It!

Related Reading: How to Fix a Clogged Furnace Condensate Drain Line.

⭐ No. 9 – AC Breaker Keeps Tripping

reset circuit breaker

If your AC circuit breaker keeps tripping, it can be from various issues:

  • Dirty filters
  • Capacitor failure
  • Power surges
  • AC compressor failure
  • Dirty coils
  • Low refrigerant levels
  • Bad electrical connection
  • Electric control failure
  • The circuit breaker itself!

⚒️ The Fix!

Unfortunately for the common homeowner, most of this isn’t a DIY job. Read more about your AC circuit breaker here: Top 9 Reasons Your AC Breaker Keeps Tripping.

Dangerous hazards such as working with electricity should be avoided unless you have experience or are a qualified professional.

⭐ No. 10 – AC Refrigerant Leak

Phyxter HVAC technician checking refrigerant charge

AC refrigerant, also known as freon, is responsible for the heat exchange from your indoor air to the outside.

So refrigerant leaks should be taken seriously.

Refrigerant leaks are one of the most common air conditioning problems and can severely reduce the efficiency of your air conditioner.

Check out our latest article to learn more: Dealing with an AC Refrigerant Leak? Here’s What to Do!

⚒️ The Fix!

If it’s just a minor leak, you can top up the system by adding refrigerant after the small leak has been identified and fixed.

This is best left to the professionals in the case of a more significant leak.

Your AC will work to its maximum efficiency if the refrigerant charge added matches the manufacturer’s specifications.

NOTE: Refrigerant is toxic and should only be handled by a professional.

It’s also illegal to vent into the atmosphere. So if you want to avoid the fines, call an HVAC professional.

If you want to learn more about refrigerant and how it works within your system, check out: What is Freon? Everything you Need to Know About Freon, Refrigerants and CFCs

⭐ No. 11 – Blown Capacitor

blown ac capacitor

If your AC turns on and off rapidly with a clicking sound, this is normally a sign of a capacitor issue.

Since your AC uses a ton of power to start up, the capacitor provides it with that initial kick to get it moving.

Think of a capacitor as a quick-discharge battery.

In the case of extreme heat, capacitors are known for overheating and failing.

Power fluctuations can also cause capacitor failure.

To learn more about how to recognize you have a bad capacitor, check out: What Causes a Blown AC Capacitor?

⚒️ The Fix!

This is sometimes best left to the professionals due to the likelihood of electric shock if you don’t know what you are doing.

These are inexpensive to replace, so if you want to DIY a fix, check out this article: The Ultimate Guide to DIY Air Conditioner Repair

⭐ No. 12 – AC Making Noise

woman annoyed by loud noises coming from her furnace

You probably have a problem if your air conditioner starts making strange noises or sounds like a jet engine.

Squealing, rattling and grinding sounds are all bad and generally mean a worse problem is about to rear its ugly head.

⚒️ The Fix!

Figuring out the different sounds can be far too complex to solve independently.

Call your local HVAC contractor to check it out if you hear any sounds that seem out of place.

Want to learn more about AC sounds and what they mean? Check out: Why Your Air Conditioner Sounds Like a Jet Engine: 4 Quick Steps for a Quieter AC

⭐ No. 13 – AC Constantly Running

AC constantly running

It’s normal for your air conditioner to run more often when it’s hot.

Your AC is built to cycle, so switching on and off is what it’s meant to do.

If it’s constantly running, then you have a problem.

This is another one of those common air conditioner problems we see.

It could be a problem with the compressor, a faulty thermostat, or problematic electrical parts.

⚒️ The Fix!

Start with adjusting the thermostat to see if you can get your AC to switch off.

Also, turn off the fan controls on the thermostat and check if that switched off your AC.

A constantly running AC could be caused by many different issues and is best left to the experts.

⭐ No. 14 – Air Conditioner Smells

air conditioning smells

Strange smells emanating out of your AC are never good.

A burning smell could be indicative of an electrical problem.

A musty smell could be from mold growth in your ducts.

A rotten egg smell or gas smell may be from a gas leak.

Smells like this are all indicators of a deeper problem.

⚒️ The Fix!

If you are starting your AC for the first time after the colder season and smell something strange, check out this handy guide on air conditioning smells and what they mean and take appropriate action: 6 Common Air Conditioner Smells and What They Mean

Related Reading: Suspect a Furnace Gas Leak? Here’s What To Do!

Related Reading: Everything You Need To Know About Your Furnace Room

⭐ No. 15 – Leaking Air Ducts

correctly supported duct work

Air ducts are built specifically to move conditioned air from one place to another.

If you have leaky ducts, this will affect the efficiency of your AC unit.

If it seems like there isn’t enough air moving around your home to keep you cool, you may have leaking ducts.

Unfortunately, a leaky duct can also affect your indoor air quality.

Holes in ductwork in your attic or wall cavities can suck up dust and other debris, causing other issues such as a frozen evaporator coil.

Constantly dirty air filters are a sign of leaks in your ductwork.

⚒️ The Fix!

Turn on your AC fan on full blast and check for leaks.

Large holes are easy to spot, but the small ones aren’t.

Most leaks will occur where ducts are connected, so check those out first.

Then, run your hand around these joints and feel for air leaks.

You can use a special foil tape to block leaks in the short term.

However, if you find old duct tape anywhere, that’s probably a problem since it’s not made to last long.

Fixing leaks properly requires the use of a special mastic sealant.

If you are uncomfortable working in your attic and don’t want to fall through it, call your local HVAC technician to complete the job.

Related Reading: Homeowners Guide to Ductwork Sealing

⭐ No. 16 – AC Compressor Failure

ac compressor cycle

If the refrigerant is the blood of your air conditioning, then the compressor is the heart.

A failure here will ensure your AC is dead in the water.

Dirty coils, a refrigerant leak, electrical malfunctions and inadequate lubrication are all common causes of a failed compressor.

⚒️ The Fix!

If you have a failed compressor, call a local HVAC company to check it out.

This can get really expensive, and if you have an old system, it might not be worth replacing, which means you need a completely new AC system.

To learn more about your AC Compressor, check out the following articles: 6 Common Causes of AC Compressor Failure and How Long Does An AC Compressor Last?

⭐ No. 17 – AC Turning On and Off Rapidly

Female HVAC Technician

An AC turning on and off rapidly is known as short cycling.

A short cycling AC can be difficult to fix, and the problem can originate from several sources.

Similar to other problems, these issues can cause short cycling:

  • Dirty air filters
  • Low refrigerant levels
  • Faulty thermostat
  • Oversized Air conditioner

⚒️ The Fix!

Start with the easy fix of checking your air filter and look out for larger problems.

Our friends at Air & Energy of NWFL have written this handy guide on dealing with AC short cycling.

If the air filter is not the cause, you will need the help of a professional.

⭐ Air Conditioner Problem No. 18 – Frozen AC Line

frozen ac line

When your AC is working correctly, it absorbs heat from the interior of your home and expels it outside.

When there are issues with the temperature exchange process, this could lead to frozen AC lines.

Your AC needs unrestricted air flow to complete this process efficiently.

Problems such as dirty filters, blocked return and supply vents, malfunctioning blower motor, blower fan, and dirty evaporator coil can all contribute to a frozen AC line.

⚒️ The Fix!

That’s easy.

Check out the following guide on identifying problems that cause freezing and learn the solutions to keep your AC running efficiently: Have a Frozen AC Line? Here’s How To Fix It!

⭐ Conclusion

Phyxter Approved Logo on Service Truck

These common air conditioning problems are typically what we see on the job.

If you notice any of these, they need to be tended immediately before they become a more significant issue.

Replacing an air filter is far easier and less expensive than replacing an AC compressor.

Replacing your entire AC system may be more cost-effective than replacing larger components, so we are big advocates for having a regular maintenance schedule.

Common AC unit problems such as these listed in most cases can be easy and cheap fixes.

So don’t cook yourself this summer; keep your AC in tip-top condition with these tips.

An efficient air conditioner is a happy air conditioner and will help keep those energy bills low for years to come with the proper attention!

And if you live in the North or Central Okanagan region, check out Phyxter Home Services.

Your choice for friendly and affordable HVAC services.

Want to learn more about your home’s HVAC system? Feel free to check out our other air conditioning articles!

Jake Gibson

Jake Gibson is a force to be reckoned with in the HVAC industry. As the CEO of Phyxter, he has made it his mission to revolutionize how contractors work. With a background in HVAC, entrepreneurship, and technology, Jake brings innovation and expertise to this traditional industry.

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