It can be both inconvenient and uncomfortable when your home's central AC unit breaks down in the middle of a heatwave, but rarely do these severe mechanical failures occur without warning. Know the signs that indicate an imminent air conditioning break down so you can fix the problem before it affects your comfort.

1. Higher Bills

Soaring energy costs can be an indicator that your AC is having trouble, especially if your energy rates haven't gone up recently. As an AC begins to struggle, it takes longer to cool your home. This extra running time can result in higher bills. An old, out of date unit can also begin costing more even if it seems to cool fine, simply because older units were never as efficient as newer ones, and they become even less efficient as they age.

2. Weak Cooling

Poor cooling is a major indicator of problems. When the AC pops on, you should feel the temperature begin to drop almost immediately. If it seems like the AC has to run for a long time just to affect minimal temperature changes, you may have a problem with the unit itself or the thermostat. Another weak cooling issue is when the AC never seems to bring the temperature down to the set level. This can affect the whole house or just a certain room.

3. Odd Noises

Other than a light hum and possibly a pop at the start when the ducts expand and contract from the temperature change, your AC unit should be relatively quiet. The most common noises that indicate a problem with the AC are squeals and whines or grinding and rattling. The former can indicate the need for lubrication or repair of parts under friction, whereas the former typically indicates a problem in the blower fan or motor. Both types of issues require a repair before your AC undergoes a complete breakdown.

4. Constant Cycling

Does it seem like your AC unit is constantly cycling on or off? If it is cycling rapidly or if it seems like it is running all the time, you likely have a problem. This is especially true if the unit is cycling rapidly but never seems to cool the house as desired. Sometimes the problem is with a failing thermostat, while in other instances the unit itself may need a repair.

5. Poor Air Quality

Finally, does air quality seem to be going down in your home? If you smell unpleasant odors when the AC pops on or if the house seems to be getting dustier than usual with no obvious cause, then there could be an issue with the AC's filtration system that needs to be addressed.

Contact an air conditioning service in your area if you suspect a problem.