If you have an older air conditioner, you may assume that one day, it will just quit — and at that point, you will replace it. But while sometimes it happens this way, it's more common for air conditioners to slowly decline in performance. The decision of whether to replace your air conditioner is not always so cut and dry. Here are four problems you may notice in older air conditioners that may indicate the time has come.

Ice Buildup

As your unit gets older, you might notice that it starts to accumulate ice on the coil. This does not mean the unit is doing a better job of cooling your home. Rather, it means all of that good coolness is staying in the coils, rather than traveling out into the air. Sometimes, ice buildup may just be due to a clogged AC filter, but if you change the filter and the problem persists, your old AC unit may be on its last legs.

Electrical Shorts

Does your air conditioner seem to trip the circuit breaker pretty regularly? If you're having to flip the circuit back on more than once or twice per season, your air conditioner probably has a short somewhere. Messing with the internal wiring in an older unit is a big task, and not one that most HVAC contractors will recommend undergoing. Replacing the AC unit is a lot easier.

Short-Cycling

As your air conditioner grows older and becomes less able to cool your home, it may turn on and off more rapidly. This sometimes happens because the motor inside the unit is overheating, triggering an emergency shut-off feature. If your AC is turning off an on every couple of minutes, it will be wasting a lot of energy, and a new unit will probably save you money in the long run.

Bumping and Rattling Noises

Even if the AC unit is still blowing cold air, bumping and rattling noises coming from inside the unit are not a good sign. This generally indicates that something has come loose inside the fan mechanism. Maybe a blade has come off the fan or a spring has popped loose. In a newer AC unit, this is something your HVAC contractor might fix, but in an older unit, it tends to be a sign that the end is nigh.

If you're not sure whether your older AC unit is struggling, arrange for an HVAC contractor to take a look.