Noisy AC Unit - What is the Landlord's Obligation

[Matt S.]

Hi All-

I have new tenants that moved in August 1st. They've been complaining that the AC unit in the 2nd bedroom is noisy. I used to live in the apartment, so I'm aware that AC unit is a little loud. However, I "house-hacked" that room for 5 years, to 4 different roommates and no one ever complained. And then rented whole whole apartment for over a year with no complaints. Additionally, it's well known by all the owners in this condo building that the wall units are a bit loud.

I scheduled an appointment to have an HVAC technician look at it and he couldn't find a solution. This was not surprising - as many other owners have ran into the same issue and there doesn't seem to be a fix.

What is my obligation at this point? Am I required to solve this? 

Thanks,

Matt