Homeowners commonly assume that, as long as their air conditioner is running, it must be working fine. However, there are many air conditioner problems that can present symptoms far before they lead to a total loss of function.

As summer rolls around and you begin using your air conditioner, be sure to keep an eye out for these issues. Addressing them sooner rather than later will help prevent bigger maintenance problems—and a surprise AC failure on a hot day. 


Under normal conditions, your air conditioning should only turn on and off a couple of times per hour. If it's turning on, off, and then on again in close succession, this pattern is known as short-cycling. The AC unit may or may not actually get your home down to the desired temperature when it begins short-cycling. 

Short cycling can be a sign of several different air conditioner problems. Sometimes, it is caused by a dirty air filter. The blocked filter forces the motor to work harder to push air through the system, causing the motor to overheat and shut off prematurely. Try changing your air filter, and see if that solves the problem. 

If changing the filter does not put an end to the short-cycling, you may have a refrigerant leak or a problem with the air conditioner's electronic control board. Both of these issues are best addressed by an HVAC professional. 

Freezing Over 

Your air conditioner should not be covered in ice or snow when it's operating. If your AC unit is freezing over, whether or not it is also short-cycling, this is a sign that something is wrong. Like short-cycling, freezing over can sometimes be caused by a dirty filter, so start by changing or cleaning yours. 

You should also trim any bushes, weeds, or shrubs near the air conditioner, and move any toys or yard equipment that may be blocking air flow to the unit. A lack of air flow to the outdoor AC unit can cause the coils to super-cool to the point that they freeze over. 

If this does not solve your problem, then there's a good chance you have a refrigerant leak. Depending on the age of your system, your HVAC contractor may either recommend repairing the leak or replacing the air conditioner. If you have an older air conditioner from the early 2000s, replacement is generally the best option since the refrigerant used in these units, known as R22, is being phased out. 

Condensate Leaks 

If you're noticing puddles of water on the floor near your air conditioner, they are probably due to a blocked condensate drain line. This line is meant to carry condensation generated by your air conditioner to a drain or sink. Sometimes, it may get clogged with mold, grime, or other debris, causing the condensate to leak out all over the floor. 

Luckily, this is often an issue you can fix on your own. Locate the end of the condensate line, and hold a wet-dry shop vac up to the line. Make sure the shop vac is turned to suction mode. With any luck, the vacuum will suck the clogging material out of the line, allowing water to pass though it once again. 

Once your line is clear, locate the vertical, capped pipe that is attached to the drain line where it emerges from the side of your air conditioner. Remove the cap, and pour a cup of bleach into the line. This will help clean out the drain line and prevent future clogs. 

Even if you do not notice any of these issues, it's a good idea to have your HVAC professional look over your air conditioner every spring before you begin using the system. This way, any problems will be caught and dealt with before you're left without air conditioning on a scorching hot day.