And why they shouldn’t be
Maybe you’re hearing these noises or something like them (it’s hard to put the sound into words. We’re HVAC professionals, not kings of onomatopoeia!).
Whatever the sound is, you can tell it’s not the typical AC noise and it sounds like something is alive in your vents. Well, first off, we sincerely hope that there is not something crawling through your vents. But ACs can make a lot of different noises. There are the noises that the AC unit can make, both normal and problematic. Then there are the noises that seem to be coming from the vents themselves.
If you are hearing noises in your vents that are driving you nuts or causing you to lose sleep, here are some of the potential causes.
Closed or blocked registers
Sofas, shelves, rugs, curtains, you name it. If anything is covering your vents, it could be causing airflow to not circulate properly, creating those strange noises. This is the first place to start. You might need to do a little room arranging but your HVAC system will thank you once all your supply and return registers are clear.
Undersized or poorly installed ducts
One of the biggest reasons you’ll hear a whining or high-pitched sound is because your system is struggling to get enough return air. The pressure and velocity increase, causing this sound. The problem is often with the ducts. They could be too narrow or undersized for your home. They could have been installed poorly, causing a return air flow problem. There could even be a lack of enough return air vents
Dirty air filters
A dirty or clogged air filter could very well be the culprit. You should be changing your HVAC filter at least every 3 months, possibly more depending on the make and model of your system. If you hear thumps, loud whining or rapid on and off cycling of your AC, check your filters. Replacing filters regularly is one of the easiest ways to keep your AC maintained and running strong.
Debris or other objects in the vents
There’s a lot that can fall into your registers and end up in the vents. Nails, screws, dirt, and other debris, anything that’s small enough to fall in can cause a racket. And if you have kids, you know very well the strange things that can end up falling in your vents.
Sagging, bent, loose or separated ducts and duct joints
Ducts can cause all sorts of racket when they are out of shape. Inspect your ducts or call in the experts to give your ducts a thorough search. Some problems can be fixed very easily with duct sealing tape (not to be confused with duct tape!), while other issues with ducts could require further repairs or replacement.
Don’t let noisy ducts drive you nuts! Try out these simple solutions on your own and if the noise persists, we’re here for you.