HVAC systems can produce a normal level of sound when working, and that's okay, but if you feel that your unit is being a bit too noisy, then it may have something to do with age or insulation. Whatever the case, be sure to check the noise rating of your unit to make sure that it is indeed being noisy.
If your unit is being noisier than it should be, don’t delay calling a trusted HVAC maintenance service provider to get things fixed. This is important because your unit can create noise pollution issues even if the sound is not performance-related.