Why Is My AC Running All Day? A San Antonio Tech Explains

Worried something is wrong with your air conditioner?

Don’t worry if… it’s a hot day outside. On hot days your AC is naturally going to work longer to maintain your desired indoor temperature. Unfortunately, there’s not much you can do about that.

You should be concerned if…

  • Your AC never stops running
  • The thermostat temperature is never reached
  • You’re always uncomfortable

If you find that any of the points above apply to you, you might have an issue a tech will need to fix.

Issues that cause your AC to run constantly include:

  • Low airflow
  • Refrigerant leak
  • Dirty coils
  • Undersized AC
  • Old AC system

We’ll go into more detail about each of these issues to help you troubleshoot them.

Want a professional to troubleshoot and repair your AC system for you?

Schedule an appointment today


Your air conditioner works in a cycle: It brings in warm air from your home, removes heat from it, then pushes cool air back into your home.

However, if your AC isn’t pulling in enough warm air, your system will run longer to compensate. We call this issue “low airflow,” which usually means something is blocking the blower (the part that pulls in air), or that the blower itself is faulty.

What to do:

  • Check your air filter and change it if it’s dirty.
  • Make sure all vents in your home are open, and that nothing is blocking them.
  • If that doesn’t fix the problem, you’ll need to contact a professional to inspect your blower.

Refrigerant is a liquid/gas that circulates throughout your AC system. Its job is to absorb heat from warm, indoor air and then dump that heat outside.

If you have low refrigerant levels, your AC will struggle to cool your home, which means it will run for long periods of time.

You’ll know you have a refrigerant leak if you notice the following signs:

  • A hissing/bubbling sound near your AC
  • Higher-than-normal indoor temperatures
  • Ice buildup on the indoor/outdoor unit or refrigerant lines

What to do: Contact a professional to check for (and repair any) refrigerant leaks in your system.

Your AC system has 2 sets of coils:

  1. The evaporator coil: Located in the air handler, the evaporator coil is the part that absorbs heat (using refrigerant) from your home’s warm indoor air. If the evaporator coil is dirty, it can’t absorb as much heat, which will make your AC run a long time.
  2. The condenser coil: Located in the outdoor unit, the condenser coil dumps the absorbed heat into the outdoor air. If these coils are dirty, then your AC will struggle to release heat, which will ultimately lead to longer cooling cycles.

Bottom line: If either of these coils become dirty, your AC will run longer, struggling to keep your home cool.

What to do:

  • Make sure no plants or other objects are blocking the outdoor unit (there should be at least 3 feet of space surrounding the unit).
  • Clear out any leaves or sticks that may have gotten stuck inside the outdoor unit.
  • If the problem persists, contact a professional to inspect your coils. (If they are dirty, a professional should clean them for you. Attempting to clean the outside coils yourself could lead to further damage to your AC system.)

Did you recently get a new AC system?

If it’s running non-stop, it may be because your AC is too small for your home.

Air conditioners are sized according to how much heat they can remove within a given timeframe. If your AC is too small, it will constantly struggle to keep your home cool and it will run longer than necessary.

What to do: Contact the company who installed your air conditioner. If they did not size your system correctly, they should be responsible for fixing it.

Make sure the professional performs a load calculation, which will tell you exactly what size system you need for your home. Then have them replace your current AC with one that is appropriately sized.

As air conditioners age, they naturally lose efficiency as parts start to wear out.

If your AC is running constantly and doesn’t keep you comfortable, it might just be time for a new system.

You’ll especially want to consider a new air conditioner if…

  • Your system is over 10 years old
  • Your warranty has expired
  • Your current AC needs frequent repairs
  • You’ve noticed higher energy bills over the years

What to do: If you think you might need a new AC, contact a professional for a quote to install a new air conditioning system.

Contact us today


We offer quick, same-day air conditioning repairs. To learn what to expect when you hire us, visit our AC repair page for more information.

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