Why Is My Car AC Blowing Hot Air? (Major Causes & Fixes)

Car AC Blowing Hot Air

It can be so annoying to find out that your car AC suddenly started blowing hot air. Your car’s AC is designed to provide cold air, to give you some sense of relief and relaxation during the hot weather. The last thing any driver will want to deal with is a car ac blowing hot air during a hot summer day.

If that is your case, don’t despair. Help is on the way! You only need to learn why your car AC is blowing hot air and how to fix it.

There are quite a lot of reasons that can cause your car AC to blow hot air. From the refrigerants to the compressor or condenser, it all has something to do with a flaw in your HVAC system. Most times, your car AC blowing hot air might be a result of a low freon.

Whatever the case might be, read on to find out all you need to know about your car AC blowing hot air and the easiest ways to fix the problem.

Why Is My Car AC Blowing Hot Air?

Here are common reasons why your car AC is blowing hot air.

1. Loss Of Refrigerant And Leaks

One of the major reasons your car’s AC starts blowing hot air is the loss of refrigerant. The car can't release cold air if there isn’t enough refrigerant (also referred to as Freon).

The role of the refrigerant is to absorb heat from your surroundings and transform them into cold air by passing them through compressors and evaporators.

When the refrigerant is low, you will experience low pressure and temperature. In most cases, the evaporator coil will freeze.

Your refrigerant level is low if there’s less freon for your compressor to pressurize, and the moisture freezes, leaving your car’s AC with nothing to work with. Most times, loss of refrigerant is caused by a leak in the system, or maybe your AC system needs servicing.

Whatever the case, it is important that you hire the services of a professional to confirm the root cause of the problem. It is always difficult to detect the exact spot of the leak. This is because antifreeze will always evaporate when exposed to the atmosphere.

2. Failing Compressor

If your car AC blows hot air when turned on, you need to check your compressor. Your compressor acts as the heart of your AC system. When it goes bad, it is impossible for refrigerant to circulate properly.

It is the duty of your AC compressor to pressurize refrigerant and pass through all the hoses that lead to your car’s cabin.

If the compressor is bad, the refrigerant can’t move, and your car has no option but to pump in hot air. In extreme cases, a bad compressor goes as far as overheating your engine.

3. Bad Condenser

The condenser plays an important role in your AC system. They handle the process of cooling the refrigerant to sustain its circulation in your car. You must understand that your refrigerant absorbs heat, humidity, and hot air from your cabin.

If the condenser is bad, there is no way the absorbed air will be cooled down. This is when you will have hot air blasting through your face.

Many factors can cause your condenser to go bad. If you are driving an old car, your condenser can grow weak and start corroding. This will prevent it from functioning properly.

There are also scenarios where a foreign object can enter the system and damage the condenser. This might also block the flow of the refrigerant.

In the event of a collision, there are chances that your condenser can break.

4. Electrical Faults

Electrical defects are one of the factors that can cause your car’s AC to blow hot. From a bad thermostat to a blown AC fuse, many electrical-related issues can inhibit your AC's performance.

Your car’s AC is an electrically-powered system. No matter how little the electrical faults are, even if it is loose or bad wiring, they can affect your AC’s delivery of cool air.

If you notice that your AC system is blowing hot air, check if you have a blown fuse. You might need to hire a professional to check the wiring to confirm that the systems are intact.

5. Bad Air Filter

The reason why your car AC is blowing hot air might be because you have a bad air filter. If the air filter is too dirty, airflow will be restricted. This will prevent smooth circulation, impacting the performance of the air conditioner. You will need to trace the position of the AC filter and check if it is clogged with dirt, debris, or dust.

A few signs can point out that your car’s AC blowing hot is caused by a bad air filter. These signs include dusty smells or loud noises from the AC when you turn it on.

6. Faulty Cooling Fans

If your cooling fans are faulty, there are great chances that your AC will blow hot. This is because there will be nothing to cool the engine. When the engine starts overheating, your AC will start blowing hot air.

You should understand that your car’s AC system is greatly interconnected. The refrigerant won’t work well if the compressor is bad, and if the electrical system is bad, the entire AC system will be turned off.

How Do I Fix My AC That Blows Hot Air?

You can fix your AC blowing hot air by addressing the root cause of the problem. Some circumstances might need you to service the HVAC system, but in some cases, you just need to discover what is wrong and fix it.

Here are easy ways to fix your AC blowing hot air.

  • Change your air filter if dirty and clogged
  • Check if the condenser is bad or clogged. Clean or replace them.
  • Address issues from your compressor
  • Trace all electrical lines and amend the faults
  • Spot the leaks and seal them. Top up the refrigerant if it is low. You must not recharge the AC until the leak is found and repaired.

We advise you to get a professional to handle your AC needs for efficient service. Do not try to do it yourself if you don’t have experience fixing an AC system.


Many reasons can cause your car AC to blow hot air. From low refrigerant levels, compressor, condenser, or bad air filters, the reason why your car AC is blowing hot air might also be tied to an electrical flaw.

It is best to get a professional to run a full diagnostic on the car and fix the problem immediately.

Frequently Asked Questions

How much does it cost to fix AC in a car?

The cost of fixing the AC in your car is determined by the model of your car and the cost of labor in your region. You must understand that it will cost less to fix the AC of a regular car brand than you will do with a luxury brand. If you are looking at an overall fix of your car’s AC, you should estimate between $1200 and $1800.

How do you know if your car’s AC is low on Freon?

You can easily tell your car AC is low on Freon if your AC is blowing hot. There will be unusual noise coming from your car’s AC. You will hear clicking sounds when your car AC is running low on Freon. This is because the AC clutch will find it hard to engage due to a lack of freon for the compressor to pressurize.