My AC Is Running But Not Cooling the House | Air Experts

Is your central air conditioner not cooling your home down to the set temperature on your thermostat? If so, you’re probably frustrated and ready to call in a professional to repair your AC.

 Before you do, though, we have some quick troubleshooting tips you can try. If your AC isn’t cooling your home, check to see if:

  1. Your thermostat is switched to ON
  2. Your air filter is dirty
  3. Your outside unit is dirty
  4. Your circuit breaker is tripped

If you’ve checked for the problems above, but your AC still isn’t cooling down the house, you probably have a larger problem that requires a professional.
In this article, we’ll:

  • Walk you through the 4 troubleshooting tips to try before calling in a professional
  • Explain the larger problems you might have if you’ve exhausted your troubleshooting options and are still experiencing the problem

4 troubleshooting tips to try before calling a pro

If your AC is running but your home isn’t cooling down, check to see if:

1. Your thermostat is switched to ON.

If your thermostat switch is set to ON, that means the blower will run constantly—even when your system isn’t cooling your home, which will result in warm air blowing from your vents.

How to fix it: Switch your thermostat to AUTO (see image below), so air only blows from your vents when the AC is cooling.

thermostat ON vs AUTO

2. Your air filter isn’t dirty.

A dirty AC filter reduces airflow in your system, causing your system to struggle to cool your home.

How to fix it: If your filter is dirty, like the filter on the right in the image below, it’s time to replace it with a new one.

dirty air filter

3. Your outdoor unit is dirty.

If your condenser (the outdoor unit that expels heat from your home) is dirty or covered in debris, it can’t properly get rid of the heat.

How to fix it: Remove any debris and try gently cleaning the condenser fins with a garden hose. Don’t use a strong stream or you’ll damage the fragile condenser fins that allow airflow to cool refrigerant.

dirty AC condenser
Example of a dirty condenser

4. Your circuit breaker is tripped.

Most ACs have 2 circuit breakers: one for the outside unit and one for the inside unit. If the outside unit’s breaker has tripped, the indoor unit will keep blowing air into your home—it will just be warm.

How to fix it: Check your breaker box to see if the outdoor unit’s breaker has tripped. If it has, switch it on. If it trips again, do not reset it. This means there’s a bigger electrical problem that a professional will need to fix.

Have you checked everything above and your AC still isn’t cooling your home? You probably need to call in a professional.
Let’s take a look at some of the problems a tech will need to fix…

Problems an AC tech will need to fix

Now, we’ll cover a few warm-air AC problems that you’ll need to contact a professional to fix. 

Problem #1: Refrigerant leak

Refrigerant is the liquid/gas responsible for absorbing heat from your home’s air. If your AC system is low on refrigerant, it won’t cool your home as well as it normally would.

Here’s the thing: Refrigerant runs in a closed loop through your system. So, if your system is low on refrigerant, it means you have a leak.

Other signs you have a refrigerant leak include:

  • Frozen refrigerant line on your outdoor unit (you’ll see the ice buildup)
  • You feel warm air from your AC vents
  • You hear a hissing/bubbling noise near the AC (this indicates a significant leak)

If you think you have a refrigerant leak, you should contact a professional to repair the leak and add refrigerant to your system. Refrigerant can be harmful if handled incorrectly, so it’s best to leave that to a pro.


Problem #2: Leaky ducts

If you have leaks in your ductwork, the hot, unconditioned air of your attic can seep into your ducts, increasing the temperature of the air that is pushed out from your AC vents.

Unfortunately, duct leaks can be hard to detect since ducts are hidden up in your attic. Signs you have leaky ducts include:

  • Higher-than-normal energy bills
  • You have rooms that don’t cool well
  • Your home is unusually dusty (from the dust in your attic)

If you have leaky ducts, you’ll need to contact a professional to seal your ducts with mastic sealant or metal tape.

Problem #3: A bad compressor

The compressor is the core of your AC system. It circulates the refrigerant that removes heat from your home’s air and dumps it outside. If your compressor isn’t pumping refrigerant like it should, your air conditioner won’t cool your home well.

AC compressor
The compressor is located in an air conditioner’s outdoor unit

The bad news: If there’s a problem with the compressor, you’ll most likely need to replace it (vs just repair it). Compressors are “hermetically sealed”, which means you can’t open them up to repair a single component.

Unfortunately, the compressor is the most expensive part of the AC. So unless your manufacturer warranty is still valid, you might be better off investing in a new unit.

Need a New Jersey tech to fix your AC?

Call us at 732-681-9090 or contact us online.

We’ll send one of our trusted AC techs to your home to figure out the problem and repair your central air conditioner—giving you the same service we’d give our own parents.

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