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How to Repair Window & Room Air Conditioners

©Don Vandervort, HomeTips

Parts of a Window Air Conditioner

If your room or window air conditioner doesn’t cool or turn on, this expert guide to AC repairs will help.

Most problems with window and room air conditioners can be categorized under one of two symptoms: they do not cool sufficiently or they do not turn on at all. Here is a closer look at how to troubleshoot and repair these issues.

Air Conditioner Doesn’t Cool

A window or room air conditioner that doesn’t cool may need to be recharged with refrigerant, but the chances are good it simply needs to be cleaned. You can do this yourself, which involves disassembling the unit, or you can call an air-conditioning professional. Before attempting the work yourself, consult your owner’s manual and make sure you have the right skills and tools to handle the task. Here is what a typical manual advises:

1Unplug the unit and carefully remove it from the window or wall. Put the air conditioner somewhere outdoors or in the garage where you can work on it.

2Remove the grille and filter and unscrew the metal case (taking care not to damage the coil’s fins).


3Wash the filter thoroughly or replace it with a new filter; most filters are readily available at most appliance stores.

4Using a vacuum with a soft brush attachment, clean the coil’s fins.

5Spray water back through the fins from the fan side (protect the wiring and the motor with plastic).

6Clean the unit up with a rag, making sure all drains that allow condensed water to drip away from the unit are open. Allow it to dry thoroughly.

7Lubrication. While you have the unit apart, lubricate the motor according to your owner’s manual.

8Finally, reassemble and reinstall the unit.

Air Conditioner Doesn’t Turn On

Window and room air conditioners draw a lot of electrical power, which can lead to less than peak performance or even complete failure. If your room air conditioner doesn’t turn on:

©Don Vandervort, HomeTips

Turn the circuit breaker all of the way off, then flip it back to “ON.”

1Be sure the unit is plugged in and turned on.

2Check that the outlet works by plugging in a light that works (only for standard-voltage models—do not plug a light into a 220/240- volt receptacle).

3If the light doesn’t go on, the circuit has probably overloaded—check the electric panel or fuse box and reset the breaker or replace the fuse.

4If the light works, it’s likely that the air conditioner’s switch is faulty or the thermostat needs adjustment or repair.

5Be sure the thermostat is set to “cool” and below room temperature.


6Refer to the owner’s manual for thermostat repair. If repairing the thermostat doesn’t solve the problem, unplug the unit and call an air conditioner repair person.

Call for free estimates from local pros now:

Join the Conversation

  • Vicki Sadler

    window unit is spitting water help………………….

    • John Carlo Torallo

      If it spits water then kindly check its air filters or drain. Make sure they are clean or clear.

  • Deborah Moon

    What would cause a unit to not cool as good as it use too?

    • John Carlo Torallo

      Here are some causes:
      Dirty filter
      Dirty fins & coils
      Undercharged refrigerant (could be there’s a leak)

  • Kelvin Whitaker

    My window air conditioner spits water from air vent

    • John Carlo Torallo

      Check both air filter and drain. Make sure they’re clean and/or unclogged.

  • Johnny Massey

    What would cause white bubbles to drip from the back corner?

  • Misty Smith

    My window unit sometimes cools for a long amount of time and then simply stops cooling and blows reg. air. Sometimes I can turn the unit off for a couple of hours, then turn it back on and it will work fine after that. Im confused as to what might be wrong as sometimes it works with no problems and then other times it stops blowing cool air after a while. Is this something easy i can fix myself?

  • R Chandra

    My window AC starts at 8 amps load & successively load increases to 13 amps and then the compressor trips. After putting off for 30 mins. the compressor works when started. What could be the fault…??

  • Angeline Kampert

    Does the clip with the wire on the front clipped on between the fins control the temperature set on the thermostat and can my condition make it too cold?

  • Chuck

    I have an 8,000 BTU Kenmore window mount. The panel lights come on using the remote or the units buttons. It beeps as you cycle through the various fan / timer / mode settings. Nothing work – fan does not come on. Suggestions?

  • Steven Loader

    My Sharp 10,000btu window A/C works fine for a while then it starts making a sharp metallic clicking sound. I tried shaking it, slapping the top and sides to no effect. I finally turned it off and even unplugged it but the noise continued for over two hours then stopped for a while then started up again but less frequently finally stopped completely after three hours.
    What causes this and how can I stop it? I can’t sleep with the noise it males.

  • wolftimber

    The most common problem is the cheap Chinese electronic circuit boards all of these things use today go bad in a couple of seasons of use, I wish I could buy one like we had when I was a teen- it had rotary knobs for the cool/fan speeds and temperature and lasted for years and years.

  • Al Magee

    my black & decker widow ac unit cool air & heat is not blowing cool air or heat both air and heat
    stop working at different times. control mode setting still work and blower. but no cold or heat.

  • Ernest Butch Johnson

    I sprayed it out with water., now I plug it in ,it trips the breaker .

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