In ideal conditions, the most you should hear from your AC unit is a low, constant, and fairly pleasant hum, which would usually just form part of the background noise of the household. Chances are that most days you hardly even notice it. Which is why many owners of an AC unit tend to get very concerned when it starts making strange noises, much as they would any item in their household.
While the temptation may come to replace the unit entirely, common sense dictates that it makes long-term financial sense to have a professional come round the house to repair whatever is causing the noise.
However knowing when the problem warrants a professional visit or not is a bit of a knack, and comes from knowing your AC unit fairly well. Not all noises are related to problems that cannot be fixed by you personally.

Know Your AC as You Know Yourself

We are not kidding when we say that you should know your air conditioning fairly intimately. Sure, you don’t have to go over each and every nut and screw and memorise each and every scratch and groove on the metal, but you should be familiar with all the moving and electronic parts.
How they fit together, whether any parts touch or rub against each other, what the purpose of it is. Doing so enables you to have a better intuitive grasp of what might be going wrong whenever things start rattling or wheezing.
It is a bad idea to do this by opening up the unit and peering inside. Doing so may void any warranty you might have on it. Instead, study your user’s manual and any schematics that might come with it.
Alternatively, as sometimes said schematics are even less intelligible than the Voynich Manuscript, you can just research the model you have online through Google. User forums and message boards may have more information on what’s happening when the appliance suffers a malfunction.

What do the Noises Mean?

It is too much of a broad topic to go over every little thing that may go wrong with your AC unit and what may be causing it, as the list can be quite broad. Instead, we’ll list the more common noises and what they may indicate instead. Don’t take this as a guarantee that this is what’s happening, rather use it as a springboard for your own investigation and diagnosis.

  • Banging and clanks.

Usually, noises like these mean that some component within the unit has managed to come loose. Chances are it hasn’t actually come away and is not flapping like a frightened bird within the machine, but it certainly needs tightening down at its bolts and screws. The screws may even need to be replaced. Other scenarios include the compressor needing realignment or, even worse, a thermostat has gone bust.

  • Squealing.

There are two possible causes of this noise. Either a moving metal part needs lubricating, or that the fan belt has come loose. It will need replacing.

  • Bubbling and gurgling.

This just means that your AC unit needs its refrigeration topped up. The gurgling noise is the sound of air bubbles in refrigeration lines. This is an easy DIY fix.

  • Loud humming or rumbling.

Usually, the AC just hums softly to itself while working. However, there may come a point when it suddenly becomes louder than usual, or even starts to rumble a bit. This just means that there’s a build-up of dust within the AC unit’s fans and other parts where there’s frequent airflow. You can either clean this up yourself, or else get a professional in to do it for you. In general, you’d get a better overall finish from a professional.

 When to Call a Professional

In general you should only call a professional if you are faced with a problem that you can’t fix yourself. In most cases, this is in-depth work that is more to do with repairing the AC than simply keeping it clean and tidy. You should also call in a professional AC repairman if you are ever uncertain as to what may be causing a sound, or where the sound is coming from.
In instances of uncertainty, trying a repair on your own will just damage the unit further. A professional would cost less to hire than replacing the entire unit because you accidentally broke it attempting a repair.
Christian Mills is a do-it-yourself type who strives to make sure his home is always comfortable and an ideal place to live. The AC however is a difficult fix for him, and when he needs that repaired he looks to Bob Heinmiller AC. You can learn more about Christian on Google+.