Reasons Why Your Home Is Still Hot Even When A/C Is Blowing Cold Air

There’s nothing worse than sweating while you’re inside your house. If you’re like most people (myself included), your first move is to turn the thermostat down to get the air conditioner running. But what if you find that your AC is already on, but it’s still hot inside? 

If your A/C is blowing cold air, but your home is still hot inside, it could be due to a simple problem like drafts or leaky air ducts. An A/C that’s not large enough for the home can also cause this problem. Be sure to check your filter and thermostat first, and open all your vents for the best airflow.

How Does an A/C System Work 

Before we dive into what’s going on with your A/C system, let’s take a moment to discuss the basics of how the whole thing works.

Most air conditioning systems (sometimes also referred to as “central air”) typically include these components: 

  • Thermostat 
  • Outdoor unit 
  • Indoor unit 
  • Expansion valve 
  • Ductwork 
  • Filter 

Contrary to what you might think, your A/C doesn’t actually produce cold air. Instead, the unit sucks in warm air and carries it over the system’s evaporator coils. The coils contain refrigerant liquid which absorbs heat from the warm air.  

Then, the air is circulated back into the home to cool the temperature. The blower fan on your indoor unit does this part, blowing the air through your home’s ductwork and into your living areas through the A/C vents. 

When the refrigerant absorbs too much heat, the liquid turns into a gas and travels to the unit’s compressor. From there, the gas is compressed down further, expelling moisture and heat along the way. When the transition is complete, the refrigerant liquid returns to the evaporator coil and starts the process over again. 

So, there’s a lot more going on inside your A/C system than you may have realized. That means that when the unit isn’t functioning properly, it could be due to several different reasons. 

Image source: U.S. Department of Energy 

Why Is My House Hot if My A/C is On?

Your Home is Drafty

A drafty house can be the source of your too-warm-for-comfort conditions. If windows and doors aren’t sealed properly, or the insulation is poor, warm air can continue to leak in faster than your A/C system can remove it. 

Older houses are more likely to have this issue than modern builds. Still, air can leak in through unexpected spaces. For example, air from an attic or around electrical outlets can make its way into your home, causing drafty conditions. Small cracks in the foundation or around the chimney may also be the culprits. 

Normally, if a drafty house is causing your problems, you’ll have the same sorts of issues in winter and may find that it’s difficult to keep the house warm, too. 

Leaky Air Ducts 

Like the air seeping in and out through windows, doors, and other openings in your home, air ducts can also be to blame if they’re not sealed properly. Older ducts or damaged ductwork can send your newly cooled air straight into your hot attic rather than into your sweltering living room. 

Leaky air ducts can cause your A/C system to work much harder than it should, too, meaning it could eventually start having problems sooner. And you’ll also probably notice higher utility bills as your A/C has to run more often than it would if your ducts were sealed up.

Your House is Too Big for Your A/C Unit 

The size A/C unit you need depends mainly on your home’s square footage. An air conditioner that’s too small for your home won’t be able to keep up with the demands of cooling all that space. As a result, you may find that no matter how long your A/C seems to run and blow cold air, the house still feels warm. 

In some cases, your A/C may struggle if you’ve made additions to your home. For example, if you add an extra bedroom or add a sun room your current air conditioning unit may not be suitable for the new square footage. That’s why it’s so important to get the right sized unit to begin with, so you’ll know you have enough coverage to keep you comfortable. 

Open Your Vents! 

If you notice your house is too hot in certain rooms or only in one side of the home, it could be because the vents are closed. Make sure your air vents are open to ensure proper airflow and good circulation throughout your house. 

You might think closing vents in unused rooms will help make the rest of your house cooler. In fact, closing off vents can make your A/C work harder as it tries to push air all the way across your home without any exit points along the way. Not only that, but if you’re trying to cool down the entire home, you’ll want to have that conditioned air flowing throughout the house, not just into certain spaces. 

You are Low on Refrigerant or Freon 

When your A/C doesn’t seem to be cooling your house well enough, one of the more unlikely causes could be that it’s low on refrigerant. In most cases, your A/C shouldn’t need regular additions of Freon. However, if you’re dealing with a refrigerant leak, your Freon could have escaped from the coils. 

If that’s the case, you’ll need to have an A/C technician come out to service your system. They’ll have to find the source of the leak, make the repairs, and recharge your system to get it up and running again. 

Clean Your Condenser 

An easy troubleshooting step you can do without the help of an HVAC repair person is clean your condenser. The condenser coils are located near your compressor, which is the part of your A/C system located outside. The condenser is what expels the heat from inside your home to the air outside. 

If your condenser gets too dirty, whether it’s covered with dirt and debris or plants, it won’t be able to release the heat from your system. Be sure to keep the condenser clear of blockages and clean, otherwise, you may be unintentionally forcing your A/C system to work too hard. In that case, it may not be able to keep up with your cooling demands.  

You Have a Dirty Air Filter 

Regularly changing your A/C filter is one of the simplest tasks you can do to keep your system working properly. Changing the filter according to the manufacturer’s recommendations is critical for the A/C system’s performance. If you don’t feel like your A/C is keeping your house as cool as it should, the filter should be one of the first things you check. 

When the filter gets clogged with dust, dirt, debris, pet dander, and other contaminants, the A/C unit will struggle to move air through the system. Left unchecked, it may become overworked and eventually break down. 

Air is Not Circulating

Another potential reason it could feel hot in your house with the A/C running is that the air isn’t circulating properly. This could be due to something simple like a clogged air filter, or it could be something more complex. A blockage in your air ducts could also be the cause, which could require a technician to come out and clean the ductwork or make repairs.  

Air flow Chart
Image Credits:

A problem with the blower could also prevent air from circulating throughout your home. Sometimes fixing this problem could be as simple as some simple cleaning and maintenance, or it could mean you need to have the blower repaired or replaced. 

There’s No Shade in the Room 

The temperature in one room compared to the next can vary significantly just based on whether there’s a tree or some other shade outside. Using window shades and window coverings can also help reduce the temperature considerably. 

If your house feels hotter during the sunniest parts of the day, this could be your issue. Even with your A/C on, the added heat from the sun might be too much for your A/C to keep up with. If this is the case, you could consider installing new windows to block UV rays, or you could use heavy-duty window shades to help keep the sun out. 

Need a New Thermostat 

A faulty thermostat can cause problems with your A/C system, especially if it’s not calibrated properly. The thermostat works by reading the temperature in the room, then signaling the A/C to turn on or off depending on your temperature settings. 

When the thermostat isn’t working correctly, it may misread the temperature in the house, preventing your A/C from operating when it should. Sometimes, the issue is something very simple, like replacing the batteries. In other cases, the wiring may be damaged or loose inside the thermostat. 

New thermostat

To find out if the temperature is accurate, use a thermometer to check the temperature compared to what’s displayed on your thermostat. 

Fan is Not Working 

If your A/C fan isn’t working, it could be due to several different reasons. It could be a power issue, a frozen evaporator coil, or even a dead capacitor. To find out what’s going on, you’ll first need to know whether the problem is with the condenser fan located outside your house or the blower located on the inside unit. 

If your fan isn’t running when you think it should, first check the settings on your thermostat. There is typically an “ON” setting, an “OFF” setting, and an “AUTO” setting. If the fan is switched off, try changing it to “ON” and see if you hear or feel it kick on. Another simple fix could be checking the circuit breaker to see if that’s the issue. 

More complex problems will require a service technician, so it helps to check these simple items first, just in case. 

Steps To Take to Fix Your A/C 300-400 words

If your A/C isn’t working properly, there are a few things you can do on your own to try to fix the issue. Follow these steps first, but if they don’t work, you’ll need to call a professional to come to evaluate your system. 

1. Check your breakers: The first and simplest thing to check is the circuit breaker. This will tell you if the power is cut off to the system. Simply switching the breaker “off” and then “on” may resolve the issue if the breaker was tripped. 

2. Check the thermostat: The next thing you should check is your thermostat. Start by double-checking your settings and that the system is turned on. You may need to replace the batteries in your thermostat from time to time, so keep an eye for any icons on your screen to let you know if it’s time to check the batteries. 

3. Check your filter: A dirty A/C filter can definitely cause performance problems with your A/C. Check your filter to see if it’s clogged and replace it with a clean filter. If this is the problem, you should notice better, cooler airflow right away. 

4. Check the compressor: Take a look at your outside unit. The compressor needs to have good airflow to work properly. Excess vegetation around the compressor or debris stuck to the side will prevent your A/C from working correctly. 

5. Inspect the fan: Look for obstructions or damage to your fan blades. If you see anything, be sure you shut off the power before you try to remove or clean the fan blades. 

If you go through these simple troubleshooting steps and haven’t found what’s causing your A/C problems, it may be time to call a service technician. Some problems are too complex for you to fix on your own, but it doesn’t hurt to rule out the simple things. 

My Car A/C Is Not Working

When your car’s air conditioner starts having problems, it can happen in a couple of different ways. Either you’ll find your A/C just won’t come on and won’t work, or you’ll notice that it starts blowing warm (and eventually hot) air. Sometimes you may find the A/C only works while the car is moving or the airflow is very weak. 

There are a few different things that could be causing your vehicle’s troubles. The A/C system in your car works like the one inside your house but on a much smaller scale. Also, your car’s A/C is subject to a much harsher environment – constant motion, vibrations, extreme temperatures, weather, and so on.

If your car A/C isn’t working, it could be due to a loss of refrigerant. When the refrigerant level gets too low, it can cause your A/C system to freeze up, and the air won’t flow properly through the condenser. 

In other cases, the condenser can get clogged by dirt, debris, leaves, trash, and other things that can get caught in the front of your vehicle while you’re driving. Keep the condenser area clear to keep your A/C in good working order. 

If you need more refrigerant, you’ll need to bring your car to the shop to have the system recharged. You may be able to find a recharge kit at your local auto parts store, but it’s always a good idea to have the system checked out as well.

How to Prevent Future Problems

Keeping your A/C in good working order just requires a little bit of simple maintenance. For example, keeping your filter changed as required and keeping the vents clear of blockages. Trim the bushes and remove vegetation from around your compressor outside to ensure proper airflow.

HVAC professionals can come out and service your system once or twice per year, which may be a good idea if you live somewhere where it gets very hot or very cold. 

As you’re heading into the winter season, don’t forget to check your system to make sure the heat is working properly. It’s easy to focus on the A/C during summer, but a functioning heat system is just as important. 


If your A/C isn’t keeping your house cool, there are a handful of problems that could be causing the issue. Many of these you can discover and take care of on your own with some simple troubleshooting. 

However, more serious problems may require a professional. Always call someone if you’re not comfortable performing the steps we discussed. 

Also, be sure to call a technician as soon as you discover the problem – don’t wait! These issues tend to get worse over time if they aren’t addressed timely. 

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