A man working on an A/C unit that isn't blowing cold air

A/C Not Blowing Cold Air? Here’s 10 Reasons Why (& How to Fix It)


You’re on your way home on a hot summer day, and you’re counting the minutes until you enter that cool wave of delicious air conditioning air in your home. You enter your home and think, “My AC is not blowing cold air. What gives?!”

But you’re home now, and your AC unit isn’t blowing cold air. Not quite the relaxed welcome you were looking forward to, huh?

Streamline Air here: we can’t tell you how many times we’ve been in your shoes. There’s nothing worse than feeling sticky, uncomfortable, and sweaty due to an A/C unit not blowing cold air.

Good news: we’ve got what you need to get your system back in action again.

For more than 20 years, we’ve been providing homeowners and businesses with quality HVAC repairs and troubleshooting for all their air conditioning system needs. If your air conditioner isn’t blowing cold air, your AC unit is likely having issues with one of its lines, pumps, or more.

Don’t sweat it, though. In this article, we’ll describe the top 10 most common reasons why an A/C unit isn’t blowing cold air — and what you can do to fix it. Let’s dive in.

Table: 10 Common reasons why an A/C unit isn’t blowing cold air

Reasons why cold air isn’t blowing through an A/C unit
1. Your thermostat settings are off
2. You have refrigerant leaks
3. Your evaporator coils might need cleaning
4. Your air filters may be dirty or need replacing
5. Your compressor might need repairs
6. Parts of your A/C unit might be clogged
7. You may have leaks in the air ducts
8. You might be experiencing issues with the circuit breakers
9. You might have damaged fan blades
10. Your A/C unit may be old and need to be replaced

1. Your thermostat settings are off

A faulty thermostat can cause your AC not to blow cold air. Blocked vents in the thermostat controls can also cause an A/C unit not to blow cold air. No obstructions should prevent airflow around your A/C unit.

What’s more, we recommend checking your owner’s manual for guidance on replacing batteries and adjusting settings in your thermostat.

If the settings aren’t the issue, consider replacing the thermostat. A smart thermostat upgrade can give you an accurate temperature reading and help with troubleshooting future thermostat-related issues.

2. You may have a refrigerant leak

If the thermostat isn’t the issue, you can also check for refrigerant leaks. Low refrigerant levels can make cooling your home a challenge for your A/C system.

Your A/C system has to work harder, all of which could saddle you with higher energy bills and potential health complications.

A note of caution: refrigerant leaks should always be diagnosed and fixed by a trained professional.An HVAC technician has the tools and knowledge needed to keep you safe and healthy. For example, your technician will measure the refrigerant with specialized tools like a multimeter.With the support of a professional, you’ll be in good hands with any refrigerant leak that could pop up.

3. Your evaporator coils might need cleaning

Streamline A/C founder, Clayton Burkhardt, working on AC unit that's not blowing cold air

One of the largest issues of HVAC units blowing warm or hot air comes from evaporator coils. Frozen or dirty evaporator coils can cause your air conditioner to stop blowing cold air.

Ice can build up around the coils and block normal airflow. When ice builds up, your air conditioner has to work extra to cool the incoming air.

As dust and dirt collects on these coils, ice is more likely to form. And ice affects the airflow around the unit.

You can help troubleshoot your evaporator coils with regular visual inspections. To troubleshoot your evaporator coils, switch off the unit and inspect the coils for grime or frost.

You can clean the coils using a vacuum cleaner with a brush attachment — or if you prefer — call a professional for quick and comprehensive coil-cleaning service.

 4. Your air filters might be dirty (and need replacement)

A multi-level apartment complex with AC units attached

Dirty air filters: they can make your AC stop blowing cold air. Air filters catch dust and debris, which helps you stay cool and relaxed.

But, over time, they clog up. When clogged, air filters block airflow and make your A/C unit work harder.

The result? A system that doesn’t work properly — and higher utility bills (ouch).

To keep your air conditioning system running smoothly, we recommend changing your dirty filters each month. Doing so will ensure you have cleaner indoor air and help you avoid the need for costly repairs.

5. You have a compressor that needs repair work

An air conditioner person working on an outdoor AC unit

Think of a heart. Its function is to pump blood into your body. The compressor is like the heart of your air conditioner, as it pumps refrigerant through the system. If the compressor fails, no cold air will come out of your A/C unit.

Dirty outdoor compressor coils can cause an A/C unit to work harder and thereby overheat. You can ensure your compressor functions well by conducting a visual inspection of your A/C unit.

What’s more, you’ll also want to check the capacitor for any ruptures or bulging, as these signs indicate damage to a compressor.

As always, regular maintenance checks can help you avoid unexpected failures in central air conditioning systems or mini split air conditioning systems. If you notice any moisture around your A/C system — or if your A/C shakes or makes any unusual noises — reach out to an air conditioner repairman for comprehensive support with your compressor.

6. Your A/C unit is clogged

Apartment complexes with AC units not blowing cold air

A clogged drain line can stop an AC unit from cooling. Clogs occur when the condensate drainpipe becomes blocked with dirt or mold. 

As a result, water backs up and triggers a safety switch that shuts down the system.

Unclogging drain lines is crucial for proper A/C functioning. You can ensure your drain lines stay clean by cleaning and replacing clogged drains often.

You might need to use a wet-dry vacuum cleaner to clear out the debris, but doing so pays off.

Keeping your A/C unit clean prevents water damage and helps restore proper airflow to your HVAC system. What’s more, keeping your AC’s drain lines clean ensures optimal performance and avoids costly repairs.

7. Leaks in the air ducts

Blocked or leaky ductwork can prevent your air conditioning unit from blowing cold air. What’s more, damaged ducts allow cool air to escape before the air reaches the rooms in your house (or business).

You can think of the ducts like a seal. When the seal breaks or cracks, an A/C system can leak cold air and allow hot air inside a business or house.

Regular inspection of your air ducts will help you identify and fix issues early. If you notice unusual temperatures or high energy bills, inspect your ducting infrastructure.

Blocked ducts often collect dust, dirt, and debris over time. Instead of crawling up into a dirty and dusty attic on your own, call a professional cleaning service. They’ll repair your air ducts in a jiff and help you keep your cool.

8. You have issues with the circuit breaker

A picture of an outdoor AC unit not blowing cold air

Often, you just have to think about the problem in a different way. And like that, a switch turns on, and a light-bulb idea emerges.

In the same way as a switch turns on or off a light bulb, your circuit breaker switch might be the cause of your A/C not blowing cold air. A/C units generally have two circuit breakers, one that’s in the house and one that’s outside of the house.

If your outside breaker is tripped, your AC unit may run but not blow cold air. To fix this issue, head outside, and reset the circuit breaker.

Your A/C should be blowing cold air in no time.

9. You have damaged fan blades on your A/C unit

An outdoor A/C unit

Damaged goods: they always spell trouble. A/C fan blades are no exception.

Damaged fan blades can block airflow and stop the AC from blowing cold air. When blades are cracked, bent, or broken, they place undue stress on the fan motor.

This stress can cause a complete malfunction of your cooling system, causing it to lose its cool (literally).

Damaged blades spin on uneven intervals and make strange noises. 

To troubleshoot damaged blades, you can start by inspecting and replacing worn or bent blades.

Doing so will save you a ton of heartache and hassle. The more you can nip structural issues in the bud — issues like damaged fan blades — the more you’ll likely save on repair and utility bills as well.

10. Your air conditioner is more than 12 years old

Traditional A/C units tend to last about 10-12 years, whereas modern-day units can last anywhere from 15-20 years with proper maintenance.

If you notice your A/C is advancing in age, it may not be blowing cold air because, well, it’s old! We hate to be the bearer of bad news, but you may need to buy a new A/C unit.

To add, A/C units use nearly 6% of all electricity in the United States — at an annual cost of about $29 billion to U.S. homeowners, according to Energy.gov. If for no other reason than to keep your utility bills down, when the time is right, you’ll want to replace your A/C unit with the latest in HVAC technology.

You can always reach out to helpful HVAC companies near you to learn about the longevity of different A/C systems and when you should replace your A/C unit.

Did you know?

A picture of A/C rust stop product

If you see a rusty one of these on your outdoor A/C, you can fix it up by lightly wire-brushing and painting it. Doing so will likely prevent refrigerant leaks and make your A/C filter drier.

The result? A longer-lasting HVAC unit.

A/C not blowing cold air? Keep your cool with the Straightforward Professionals

A person working on an AC unit

If you’ve come to your home or business and found that your air conditioning system isn’t blowing cold air, you might be having one of the following issues:

  1. Your thermostat settings are off
  2. You may have refrigerant leaks
  3. Your evaporator coils might need cleaning
  4. Your air filters may be dirty or need replacing
  5. Your compressor might need repairs
  6. Parts of your A/C unit might be clogged
  7. You may have leaks in the air ducts
  8. You might be experiencing issues with the circuit breakers
  9. You might have damaged fan blades on your hands
  10. Your A/C unit may be old and need to be replaced

These are some of the most common causes of an AC unit running but blowing warm air — and not cool air. When you’ve done all that you can, but still can’t find relief, it’s time to call an air conditioning repair company for help.

An experienced HVAC technician can inspect all the parts of your A/C and diagnose why your AC is running but not blowing cool air. If you live in Florida, the Straightforward Professionals at Streamline A/C are more than willing to come to you.

Over the last 20 years, we’ve repaired more than 15,000 air conditioning units and served over 1,000 clients. If you’re looking to keep your business or home cool and comfortable, look no further than Florida’s most trusted HVAC repair team, Streamline Heating and Air.

To receive an estimate on air conditioning services, contact us today!

Frequently asked questions about AC repair work

A person working on an outdoor A/C unit

Why is my air conditioner not blowing cold air?

Some of the most common reasons your A/C may not be blowing cold air is because of broken components or simple human error. The most common reasons an A/C system stops blowing cold air are due to issues with:

  • Thermostat settings
  • Refrigerant leaks
  • Evaporator coils
  • Air filters
  • The compressor
  • Clogged components
  • Leaky air ducts
  • Tripped circuit breakers
  • Damaged fan blades
  • The age of your A/C unit

Plenty of do-it-yourself solutions exist. But, if you feel more comfortable receiving the help of an expert, you can always reach out to a heating and air conditioning specialist to help you troubleshoot the reason why your A/C system isn’t blowing cold air.

How often should I check my A/C for structural repairs and maintenance?

We recommend air conditioning tune-ups and maintenance at least once a year. Spring is one of the best times to conduct your annual HVAC tune-up.

That way, your HVAC system will be ready to blow cold air long and strong in time for the sweltering summer months.

What can I do to make sure my AC keeps blowing cold air year-round?

You can ensure your A/C keeps blowing cold air year-round by following these extra helpful and simple maintenance tips:

  • Keep an eye out for dirt and debris around your A/C unit
  • Ensure proper indoor air quality
  • Ensure refrigerant fluid — and other fluids — are at proper levels

If you think your unit has become clogged with debris — or if you need help with an A/C unit that stops blowing cold air — don’t hesitate to reach out to any of our master HVAC technicians. We’d be more than willing to troubleshoot the issue with you.

Meet the Straightforward Professionals at Streamline A/C!

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