I recently moved into a brand-new home in Arizona this March, and I'm really struggling with an extremely loud AC hum that's driving me crazy. The AC runs frequently during the summer, which is normal here, but I've never dealt with noise like this before. The HVAC team replaced the capacitor, claiming it was going to fail, but that hasn't resolved anything. They insist the noise level is normal, yet I can hear it from almost every room in my 1841sqft single-story house. I hear it even over noise machines or TV playing, and when the AC turns off, it's such a relief!
I'm looking for suggestions on how to soundproof my windows while still letting in light because they're newly sealed. With the AC unit situated between two windows, I suspect that contributes to the noise amplification. Any tips on sound barriers outside that won't interfere with airflow would also be greatly appreciated. I want to solve this issue before my next inspection in a year and a half!
3 Answers
It sounds like you might have a loose shorting coil on a shaded pole relay. When those come loose, they can cause a lot of noise. Definitely worth checking out! Good thing you're getting a sound meter – that should help you figure out what’s going on.
If they replaced the capacitor already, it could indicate low refrigerant charge. New condensing units come precharged for a certain line length. If the installer didn’t measure the lines correctly and add enough refrigerant, that could cause issues. It's a common oversight since some installers skip proper checks. You might want to look into this based on guidelines in your equipment manual.
Since you only hear the noise inside, it’s possible the blower is what’s causing it. Check where your blower is located – it could be in your attic or a closet. If you can find the filter location, that’s usually where your blower is. Try removing the filter and see if the noise becomes louder when the AC is on. If that’s the source, it’ll be a lot louder in rooms with vents. Otherwise, it might be that your outside unit isn't the real culprit.