Air conditioners can get through a typical year with standard maintenance, but when something starts to go wrong, the problem can show itself in a variety of ways. Keeping an eye out for unusual sounds and smells, as well as big changes to your electric bill, can help you catch problems early so they can be repaired before they get worse or become a health hazard.

Rattling, Banging, or Squealing Sounds

When an air conditioner starts making loud noises that aren't normally there, the problem could come from several different places. Most of these sounds will come from moving components, but there are some, like your ducts, that don't necessarily have to be moving in order to make loud noises.

If your ducts aren't properly sealed or if they're starting to get old, banging sounds can result from a difference in air pressure inside the ducts. The occasional quiet bang isn't often a sign of trouble, but if it happens regularly or with increasing volume, your ducts should be inspected.

Moving parts like fan belts or your blower motor can also cause loud shrill sounds. Belts that are misaligned or old and worn may need to be replaced. The blower motor, on the other hand, has bearings that, when dried out or failing, can cause a squealing sound as metal rubs against metal, and will need immediate repair.

Rattling sounds can happen as a result of loose panels, debris in your outdoor unit, or a misaligned fan that's causing fan blades to either wobble or hit the fan casing. Since this sound usually indicates physical damage of some kind, call a technician as soon as possible.

Foul Odors from Vents

Generally, the air that comes from your ducts should be odorless. If you start smelling foul odors coming from your vents, this could hint at one of a few different problems depending on what you're smelling.

A musty odor, for example, can come about if your condensate drain line is clogged, which can cause water to back up and potentially spillover, which in turn can cause water damage or cause mold to grow. Likewise, a metallic or burning smell could be the result of one of your air conditioner's components burning or overheating, which is something that should be looked at immediately.

While some smells can hint at something more dangerous than others, any foul odor generally indicates something that needs fixing, sometimes urgently.

Spike in Electric Bills

You can expect to see some variation in your bills due to changes in weather, but if you see a noticeable spike that doesn't go away even when the weather cools, this could be a sign that part of your HVAC system needs inspection and repair. The most common culprit behind rising electric bills is your air duct system, and there are two main problems that can occur with your ducts that make them noticeably less efficient.

The first is failing insulation. Your ducts are insulated to make sure that cold air stays cold as it travels to each room in your house. If your insulation is failing, your cold air may warm up some before it reaches the vents, which means it will take longer for your house to cool and result in your air conditioner running for longer periods of time. Failing insulation also makes your home more susceptible to mold and mildew growth.

The second is damage or wear and tear. Gaps and holes and failing seals can let out 20 to 30 percent of cool air on average, and if your ducts are very old or have suffered infestations from pests that damage them, this number could be even higher.

When your energy bill starts to rise, call to have your ducts inspected and repaired by a professional. To make sure no major duct-related problems sneak up on you, have your ducts inspected every few years or when you have your air conditioner serviced annually. Visit a website like http://www.coeheatcool.com to learn more.