My Air Conditioner is Breaking and Now I Hear a Rattle -Help!

In most cases, it is cheaper and less effort to simply fix a window air conditioner than replace it with a new unit. Did you know that loose parts and a faulty installation are the two most common reasons you're hearing these noises?

But you can repair both of these yourself.

Bad Installation

There's nothing to be emabarassed about if you did it yourself - we're human and prone to error. Typically, a rattling window or window air conditioner unit means the unit isn't sitting right on the window sill or frame. On most air conditioners, there is a notch, or series of notches that are extra wide and designed to work with most sills and windows - even older ones. The manufacturer also places extra padding, foam, insulation, and support around these areas. The reason is because these areas are in contact with the most solid wood, or frame, and thus most of the weight of the unit is placed in that area, or distributed there.

So, if the unit isn't sitting right, the moving parts (fan) and heavy pieces that generate noise (compressor) no longer have the cushion, or support. Thus the unit or entire window will vibrate or rattle.

To fix this, look to make sure you are installing the unit correctly. And use the provided screws to fasten the unit to the window, because this will further brace the window and window unit.

Parts are loose

Almost everyone knows that a/c units having moving parts. Fans and compressors are a few of the more noticeable things that can go wrong and "rattle" if they become loose. The obvious answer to fixing a loose part is to reattach it. Very simple household tools are all that is needed. In other words, you can do it. The most common repair is the fan being loose.

This is by no means an exhaustive list, because so many more things can be causing the problem. You can discover more causes for the rattling by clicking the link to my free energy blog.

What about central A/C units? What can I do there if I hear a rattling?

There's less user-serviceable features about a central air conditioner. Actually, the window unit doesn't strictly have user serviceable features either, but the assembly is easier to get to. Still, the most prominent issue with central a/c noise is debris. Leaves, sticks, twigs, branches, dirt, stones, roofing tiles, screws, nails, tools - you name it, somehow ends up in the unit (at the top) and coming in contact with the fan. This causes the noise.

Simply remove the debris and noise should stop. It should be readily visible. Fortunately, the fan housing is very easy to access. If you can't pull the obstruction out with tweezers or pliers, turn the unit off completely (so the fan doesn't turn on when you're working) and remove the upper housing. Then its just a matter of removing the problem debris.

Aren't you happy? You may have just saved a potentially expensive service call.