Forgetting to change your air filter is one of the best ways to ruin your air conditioner.
When the filter gets too dirty and blocks air flow over the evaporator coil, your coil gets too cold and freezes up.
When this unfortunately happens, liquid refrigerant flows back to the compressor outside. Since compressors will only compress refrigerants in gas form, this liquid refrigerant destroys the compressor. This will require you to substitute your compressor, which is really expensive. Or, you may have to replace your outside unit. Remember to check your filter once a month and change it as needed. Are you convinced that closing vents in unused rooms can save you money? Consider: closing the vents can cause your evaporator coil to freeze up just like the dirty air filter. Closing air vents increases pressure in the duct system, but your regular air conditioner blower is only designed to work with a certain amount of pressure. Extra pressure slows the blower speed down. Slower blower speeds mean less air flow over the evaporator coil, causing the same complications as a dirty air filter. So, be sure to keep your air vents open. Also, you might think your air conditioner is ugly, tempting you to decide that you want to cover the outside with bushes or a fence or a decorative cover. Covering the outside device causes the air conditioner’s compressor to overheat. Your air conditioner works like a heat sponge, absorbing heat from your home’s air and dumping that heat outside. But, if the outside device is covered by a fence, cover, or bush, it’s hard for it to release that heat, causing the air conditioner to run longer, eventually overheating the compressor! Don’t cover your outside device, and be sure to keep at least two feet of area free around the device on all sides.