Is it Normal for a Central Air Conditioner to Run Constantly?

It’s summer time and your central AC is running non-stop.

Is this normal?
Well, because it’s hotter outside, it’s normal for a central air conditioner to run without cycling on and off as often.

Also, running with fewer cycles (turning on and off) is not necessarily a bad thing.

In fact, running longer can be positive because it:

  • Helps dehumidify your home
  • Can decrease wear and tear on your system from less starting and stopping

Ask yourself this:

  • Are you staying comfortable? (home is reaching thermostat temp on very hot days and airflow from vents is normal)
  • Are your energy bills about the same as they were last year?

If you answered yes to these, there’s probably not a problem.

When you should be concerned:

  • When your air conditioner runs constantly (it literally never stops)
  • You’re never comfortable
  • The thermostat temp is never reached

These are signs something is wrong and needs correcting.

If that’s you, here are few things that could be causing your air conditioner to run constantly..

Undersized air conditioner

Signs this is the problem:

  • You just got a new air conditioner
  • Air from vents is cool and the airflow is normal, but your home does not reach the thermostat temperature on hot days.
  • Frozen evaporator coil (refrigerant tubes in the inside unit)

Air conditioners must be sized properly for each home. An undersized system struggles to cool your home, which is why it’s running constantly. This constant running will reduce pressure in the evaporator (cooling) coil until it freezes over.

This is dangerous because the freezing can cause liquid refrigerant to flood back to the compressor and damage it. And the compressor is an expensive part you don’t want to replace.

What you should do: Get an air conditioning contractor to perform a heat load calculation on your home. This will determine what air conditioner size (measured in tons) your home needs.

Restricted/reduced airflow

Signs this is the problem:

  • Air from vents is cool but the airflow is weak
  • Dirty air filter
  • Closed and or blocked vents
  • Improperly sized or damaged ductwork
  • Frozen evaporator coil
  • Bad blower motor

Your air conditioner may be running constantly because it can’t supply your home with enough cool air. Either something is wrong with the blower itself, or something is blocking air to the blower.

What you should do:

  • Change your air filter if it’s dirty (here’s a simple air filter buyer’s guide).
  • Open all supply vents (yes, even in rooms you’re not using).
  • Make sure no return grilles are blocked by drapes, curtains or furniture.
  • Determine if your ducts are leaking

Low refrigerant

Signs this is the problem:

  • Air conditioner isn’t blowing any cool air/air isn’t cool when it’s hot outside.
  • Frozen evaporator coil
  • You can spot a refrigerant leak anywhere in the system

What you should doCall an AC contractor to have them check your refrigerant levels. If the refrigerant level is low, the repair person should look for a refrigerant leak.

Dirty evaporator and/or condenser coil

Signs this is the problem:

  • Similar symptoms of low refrigerant
  • You can visually see the coils are dirty

The evaporator coil in the inside unit absorbs heat from your air. The condenser coil in the outside unit disperses that heat outside.

Dirt on the evaporator coil prevents refrigerant from absorbing heat from your air. Similarly, dirt on the outside unit prevents heat from escaping and the outside fan can’t cool the coil.

In either scenario, your air conditioner will run constantly since it’s struggling to absorb heat from your home and/or release heat outside.

What you should doCall a professional to schedule air conditioner maintenance visit. This visit can include cleaning the inside and outside units and other maintenance tasks that will increase the efficiency of the AC.

Want more professional advice? Ask an expert!

If you’re concerned about your central air conditioner, ask one of our AC experts for help.