Why Is My Air Conditioner Running Longer?

If you've been in your house a long time, you may notice that your air conditioner runs for longer periods of time than it used to. If that's the case, it's quite possible that your electric bill hasn't just been going up because the cost of electricity has been increasing. Here are some of the reasons that your air conditioner might be running longer, and how you can fix the issues to bring your electricity costs back down: 

Dirty Air Filters

Dirty air filters are one of the biggest culprits in bad energy efficiency for air conditioners. The reason that they make your air conditioner run longer is because as they fill up with dirt, less air can get through.

Your air conditioner uses the same amount of power no matter how much air passes through at a given time. So be sure to regularly change your air filters as directed by the manufacturer to cool as much air as possible at once.


Have you added a new room or converted a basement or garage into living space? If so, your air conditioner is running longer to cover the extra space.

While you might think that it makes sense to just let your air conditioner run longer, an air conditioner that wasn't originally sized to the square footage that it's covering doesn't run as efficiently as one that was. For full energy efficiency, upgrade to a new air conditioner or install a separate ductless or window air conditioner to cover the new room.

Refrigerant Leak

A refrigerant leak could also be to blame for a longer running time. A refrigerant leak causes an air conditioner to lose cooling power so that the air that comes out of it isn't as cold. Because there is less temperature difference between the cooled air and the room temperature, it takes the air conditioner longer to cool down the house.

As a general rule of thumb, the air coming out of the vents should be 15-20 degrees colder than the room. If the temperature difference is lower, a refrigerant leak is often the cause.

Leaky Ducts

Air ducts that are damaged can send cold air into the attic instead of into the home. If not repaired, the air conditioner will be sending less air at a time into the home and end up running longer.

To have your air conditioner expected or to schedule a repair, contact a local air conditioning repair contractor, such as Greers Service Company Inc, for more information.