Schedule An Appointment

What Causes Air Conditioners to Leak Water?

  • July 19, 2013

To understand what causes air conditioners to leak water, first notice that it’s called an air “conditioner” and not an air cooler. Early units were actually invented primarily to reduce indoor humidity in printing factories where dry air was necessary for production. Cooling was simply a pleasant by-product of the process. Because humid air holds more heat and dry air feels cooler, today’s A/C units still extract humidity from the air in addition to absorbing heat. In fact, on a humid summer day in North Carolina, the evaporator coil on a large central A/C unit can wring as much as 20 gallons of water from the air.

All that liquid’s got to go somewhere and down the condensate drain into the sewer is the right place for it. When it leaks and damages property and possessions instead, questions must be asked.

Here are some answers to what causes air conditioners to leak water:

  1. Improper installation. Condensate dripping from an evaporator coil first collects in a drain pan. If the A/C unit isn’t installed perfectly level—a basic requirement of proper installation—and the flow of condensate is heavy, water may overflow the sides of the drain pan.
  2. Clogged drain tube. Condensate passes from the drain pan into a tube that conveys it to a household drain. Clogged drain tubes are fairly common due to growth of mold or algae. An HVAC technician can clear the blockage and treat the drain pan with time-release biocide tablets to prevent recurrence.
  3. Coil icing. Ice forming on the evaporator coil due to low refrigerant charge or obstructed airflow can be indistinguishable from a condensate leak. If the ice formation on the coil extends beyond the limits of the condensate pan, when the unit turns off and the ice melts, water may be observed pooling under the air conditioner.

Serving Aberdeen and all of Moore County, Comfort Services offers solutions to indoor comfort challenges. If you notice water around an A/C that shouldn’t be there, let one of our professional technicians inspect your system and tell you exactly what causes air conditioners to leak water.