My air conditioner is making bad noises. Why?

Which would you rather do, fix a noisy air conditioner or buy a new one? If you answered “fix it” – good for you! The most common causes of strange noises coming from window air conditioners is either faulty installation or loose parts in the unit.

But you can repair both of these yourself.

Bad Installation

Installing a window unit isn’t hard, but even a slight misplacement of the unit can cause a problem. Usually, a noisy air conditioner that is installed in a window isn’t sitting properly on the frame or window itself. 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. Extra padding, foam and shock absorbent materials are placed near these slots by the manufacturer. 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. The result is a very audible rattling or noise coming from the window.

So, all you have to do is check to make sure the unit is sitting properly on the window sill or frame. 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

Modern air conditioners have 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. This might require glue, pliers, maybe a screwdriver. So, what I’m trying to say is…you can do it. Don’t be intimidated. 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. And this is usually the reason you hear a rattle or thump.

The solution: Remove the obstruction or debris. 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.

You should feel proud – you just saved a lot of money by not calling someone to look at your “problem”!