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Why Is My AC Running Non-Stop?

August 31, 2017

An AC that runs non-stop wastes energy and doesn’t cool your home very well.

But before you worry that something’s wrong with your AC, first check if it’s a particularly hot/humid day.

You see, in addition to cooling your home, an important function of your air conditioner is to remove humidity from your home’s air. And on very humid days, your AC has to work twice as hard to remove the extra humidity, which steals cooling power from your AC and forces the system to work longer to reach the set temperature.

If the weather is normal, though, your AC may have one of the following common problems:

  1. Clogged air filter

  2. Closed vents

  3. Grimy blower fan

  4. Low refrigerant levels

  5. Dirty refrigerant coils

  6. AC is too old

Let’s go into more detail about each of these problems and how to solve them.

#1: Clogged air filter

If your filter looks like the one on the right, it’s time to replace it.

A clogged filter essentially “suffocates” your air conditioner because it restricts the amount of air your system can bring in. And the less warm, humid air your system breathes in, the less cool air it blows out.

Imagine trying to breathe with a blanket over your mouth. Makes it pretty difficult, right?

This is what a clogged filter does to your AC. And if your AC system can’t breathe easily because the filter is clogged, it’ll run non-stop trying to cool your home.

Solution

The solution is pretty simple: Just change the air filter if it’s dirty. In the heavy cooling summer months we recommend changing your air filter every month for best efficiency.

#2: Closed vents

Your home has 2 types of vents:

  1. Supply vents that push out cool air to your home

  2. Return vents which pull in warm air from your home to be cooled

If either kind of vent is closed, it could cause your AC to run non-stop.

An open return vent

Closed return vents “suffocate” or restrict airflow to your AC system, which could cause it to run non-stop trying to cool your home.

Open supply vents

Closed supply vents are also problematic. Sometimes we see homeowners close supply vents in rooms they don’t use, thinking they’ll save money. However, by closing supply vents you actually make your AC work harder and longer, which makes your energy bills go way up.

To learn more about closing your vents, check out our article, “Should I Close My Air Conditioning Vents in Unused Rooms to Save Money?

Solution

Leave your vents open, even in unoccupied rooms.

#3: Grimy blower fan

A grimy blower fan

Your blower fan sits inside of your air handler, and it’s the component that pushes air through your AC system into your home.

If your blower fan is dirty, then it reduces the amount of cold air that will enter your home. That means your AC has to run longer trying to reach your set thermostat temperature.

Solution

Follow these troubleshooting steps to clean your blower:

  1. Locate your blower fan in your indoor air handler (most often found in your attic). The blower fan sits inside a metal cabinet and won’t be visible until you remove the metal door with a screwdriver.

  2. Look for a visible layer of dust or grime on the blower.

  3. Use a toothbrush to loosen up the dirt, then use a vacuum to suck up all the grime. (Be careful not to pinch your fingers as the fan will spin freely when you clean it.)

Cleaning the blower fan is difficult and can be a major time drain. So if you don’t have the time or patience, have a professional do the job for you.

#4: Low refrigerant levels

Ice buildup around the indoor air handler indicates low refrigerant levels

Refrigerant is the liquid/gas that absorbs heat from your home’s air, which is what makes the air feel cold.

If your system is low on refrigerant (which usually means there’s a refrigerant leak), then your AC can’t cool your home’s air and will run longer trying to reach your set thermostat temperature.

If you hear a hissing/bubbling noise, or you notice ice around the evaporator coil, those are signs you have a refrigerant leak.

Solution

Have a professional inspect your AC system for refrigerant leaks. Only a certified professional should handle refrigerant because it’s a toxic substance.

#5: Dirty refrigerant coils

Dirty refrigerant coils

If your refrigerant coils (also called evaporator coils) are covered in dust/dirt, then it creates a wall between the warm air and the cold refrigerant. This dirt barrier prevents your refrigerant from absorbing the heat out of your home’s air, which means your AC will run longer to try and cool your home.

Solution

You shouldn’t attempt to clean refrigerant coils yourself because they’re very sensitive, so instead call a professional to clean your evaporator coil for you.

#6: AC is too old

How old is your AC? If your air conditioner is 10+ years old, then maybe it just can’t keep up anymore.

Like any piece of mechanical equipment, air conditioners wear out over time. So if your AC is running non-stop, it may be time to install a new one.

Curious about the cost of a new AC? Read our article, “How Much Does It Cost to Install a Central Air Conditioner in Florida?

Solution

Contact a professional for a price estimate on a new air conditioner.

Need an AC repair? Or need a new AC?


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