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Why Is My AC Constantly Running? A Phoenix Tech Answers

Notice your AC running non-stop?

If you’re in the middle of a scorching Phoenix summer, it’s common for your AC to run longer than normal. So if it’s a hot day, there’s no need to worry.

However, if it’s not especially hot outside, OR your AC is running constantly and NOT keeping your home comfortable, then there’s a problem that needs to be fixed.

In this article, we will discuss:

Need a fast and reliable AC repair from a Phoenix pro? We can help!

DIY fixes for an AC running non-stop

One of the most common reasons an air conditioner runs constantly is restricted airflow.

Your AC needs a certain amount of airflow in order to supply your home with cool air. If something is blocking the airflow to your AC, your system will run longer in an effort to bring in a sufficient amount of air.

Before you contact a professional, try these simple fixes for low airflow.

#1: Check your air filter

A dirty air filter can restrict airflow to the indoor part of your AC, which causes your system to run longer in an effort to bring in sufficient air to be cooled.

Go to your air filter and check it to see if it is dirty. If it looks dirty, replace it.

Dirty Air Filter

A clean (left) vs dirty (right) air filter

In the future, check the filter at least once a month and change it out when it’s clogged with dirt.

#2: Open all supply vents

Your AC may not be getting proper airflow if vents are closed. Similar to a clogged filter, this also causes your AC to run longer than normal to cool your home.

A supply vent

A supply vent

To fix this, you’ll want to open all supply vents (the ones that blow air into your home)—including vents in unused rooms. This will help your AC bring in a sufficient amount of air.

#3: Make sure nothing is blocking the return vent(s)

The return vent is where warm air enters your air conditioner to be cooled. If something is blocking it, your AC will run non-stop.

A Return Vent

A return vent is located on a wall or ceiling

You may have more than one return vent, depending on the design of your HVAC system. Go to your return vent(s) and make sure furniture or curtains are not blocking them.

When to call a professional for help

Tried the fixes above but your AC is still running too long? If so, you might need to call a professional air conditioning contractor to fix one or more of the following problems.

#1: Refrigerant leak

Refrigerant is a liquid/gas substance that circulates throughout your AC. Its purpose is to absorb heat from warm, indoor air. After it absorbs warmth from indoor air, the refrigerant is carried outside where it releases the heat into the outdoor air via the condenser (outdoor AC unit).

AC refrigerant cycle

A diagram of the refrigerant cycle in a central AC

Because refrigerant is so essential to the process of cooling your home, you can think of it as the lifeblood of your AC system. If your AC is low on refrigerant, it means your air conditioner will struggle to cool your home, which means the system will run longer.

The main cause of low refrigerant is a refrigerant leak. Usually, refrigerant leaks occur in the conduit lines that run between the indoor and outdoor units, or near the compressor or evaporator coil.

Besides the fact that refrigerant is potentially harmful to humans, repairing a refrigerant leak can be complex. You’ll need to contact an experienced HVAC technician to find and fix the leak.

How do I know if I have a refrigerant leak?

You may have a refrigerant leak if you notice signs such as:

#2: Dirty components

If components in your air conditioner are dirty, they can prevent your AC from running efficiently, which makes it run longer.

Two components in your AC are especially prone to get dirty:

  1. Condenser coils: Because the condenser is located outside, dirt and debris can easily clog the coils, which prevent refrigerant from releasing heat into the outdoor air.
  2. Evaporator coils: The evaporator coil is located in the inside unit of your AC system. It’s the part that essentially cools your home’s air. If dirt is blocking the coils, it makes it tough for refrigerant to absorb heat from your home’s air.

Because the coils are delicate, it’s best to let a professional carefully clean them with the proper equipment.

How do I know if my AC coils are dirty?

You can go outside and visually inspect the outdoor unit to see if the coils are caked in dust. If you have a dirty evaporator coil, you’ll notice things such as:

  • A persistent moldy smell
  • Higher-than-normal energy bills
  • Air that feels warmer coming from the vents

#3: Undersized AC

If your system is too small for your home’s cooling needs, it will constantly run but rarely deliver enough cool air.

To determine if your AC was sized correctly, you’ll need to have an HVAC pro perform a load calculation. This complex calculation will tell you what size AC you need based on factors specific to your home, such as:

  • Square footage
  • The number of people living in your home
  • Your home’s insulation levels
  • The condition of your ductwork
  • And much more

How do I know if my AC is undersized?

The only accurate way is to know is to have a professional perform a load calculation. But these tell-tale signs also indicate that your AC may be undersized:

  • Your home never feels cool enough
  • You consistently have high energy bills
  • Your home has several hot and cold spots

Ready to schedule an AC repair?

We’ve serviced air conditioners in the Phoenix area since 1955. Call (602) 842-0009 or schedule an appointment online today and we can send one of our trusted technicians to repair your AC ASAP.