5 Things That Can Go Wrong With Your Air Conditioning

A home that's air-conditioned and blissfully cool is truly one of life's "creature comforts," especially in the humid, sticky days that lie ahead. So finding out your AC unit isn't working properly can leave you — quite literally — hot under the collar! What to do?

"There is no substitute for getting a good technician to make a visual inspection of your ducts, joints, seams and other parts of your unit," says Dave Borowski, spokesperson for Direct Energy Protection Plans. Here are some common reasons an AC unit might be wasting energy, working ineffectively, or not working at all:

  • Faulty ducts that leak air: "Duct work has been identified at the #1 waste of energy in homes," notes Borowski. Because there is no building code for duct work, shoddy workmanship can easily go undetected. "And for the most part, duct work is held together with duct tape, which eventually dries our and gives up." Leaking duct work causes two problems: One, it wastes valuable cooled air. Two, it brings unwanted contaminants into your home—moisture, mold, odors and allergens.
  • Dirty coils: Air conditioners don't work by adding coolness to air, but rather by sucking heat out of it. "The AC electro-mechanically and chemically (with a refrigerant) absorbs heat from your home and rejects that heat outside," says Borowski. "To absorb heat, coils have to be cold and slime free." Even in the cleanest of homes, there are bacteria, pollutants and airborne contaminants — and when this mix hits the wet air conditioning coil, it turns slimy. "That slime is a great insulator, which means the AC can't absorb the heat from your home."
  • A broken condenser fan: The fan works in conjunction with your air conditioner's coils, and works to expel air outdoors. "A coil is like the radiator on your car," explains Borowski. "If the fan needs isn't running at peak and performance to push air across it, you'll overheat." And if the fan can't reject heat efficiently, your energy bills will be sky high, and your AC performance will be unacceptably low.
  • TXV issues: Think of the thermal expansion valve as a modulating unit inside your AC. It's like a needle moving back and forth to regular the amount of refrigerant that passes through the unit, depending on how much heating or cooling is needed. "If it's not moving properly, it can either flood the system or restrict the flow — either way, it's not good," notes Borowski. How would you know? Again, your air conditioner's performance would be low and your energy bills high.
  • The age of the unit: Even the best air conditioning units don't last forever — and neither do their thermostats. "The useful life expectancy of an AC unit is usually between seven and 10 years—depending on where you are in the U.S, and the number of heating and cooling hours you use," says Borowski.

Higher energy bills and lower performance are sure signs your AC unit needs fixing — but symptoms like these might also be clues:

  • Moldy odors or other smells
  • A noisy air flow, or bumping noises when the blower starts up
  • Streaks of what looks like "dirt" on air conditioning grills
  • Recurrent power failures in your area (voltage issues can really affect AC units)

The good news? "It is quite easy for a trained, competent technician with the right diagnostic tools to make a battery of tests and quickly ascertain if corrective action is needed," says Borowski. Regular maintenance is also key: it will not only prolong the life of your unit, but help you keep your cool.