Thank you for all the replies. There's a lot to think over and consider - but at least now we have a better idea.

We have a patio that has 3 big AC compressors within 25 feet. They are very loud and quite annoying. Granted they are all for restaurants so they are bigger than a typical compressor that would be used for a residence. If we had the ability to block installation of these we definitely would have. Personally, I wouldn't let them put it on the roof without getting some monetary compensation.

I have several ductless units & they do work much better at the ground level in a shaded area.
Any true professional will advise against putting them on roof or in direct Sun, as they will run constantly & cost you dearly on electric consumption.

Quote:

My next door neighbor has a compressor on their roof and I can hear it very clearly when I'm trying to go to sleep if I don't have my AC on.

My neighbor added central AC and put their compressor on the roof. Didn't affect me at all.

Thank you for all the replies!

To answer a question asked earlier:
- yes, there is a shared backyard, but the contractor said it's more efficient to have the compressor on the top vs street level (less "pushing")

- sounds like noise and vibration could be a big concern

@I_heart_JC - how is the noise and vibration from your apartment? Is it directly above your unit?

- we will definitely get a lawyer involved if this is going ahead - however, too many concerns at this point...

Pitfalls: Your roof will leak and everything in your home will be destroyed. The vibration and noise will keep you up at night. You will never be able to enjoy a roof deck up there with a loud AC unit cooling the downstairs neighbors. Compressors should be in the shade in the back of a structure, not on the roof where it's much hotter and they have to work much harder.

Say no.

if you do agree to let your neighbor put it in (and/or if you put one in yourself), make sure the exhaust points outward, onto the street or back yard.

there's a big A/C compressor on my roof, and the blast of heated exhaust it creates makes half of the roof uninhabitable. I'm a renter, as is the business who installed the A/C. I really wish the landlord had thought of this when giving the go-ahead.

Sounds tricky. Best option is to get a real estate attorney involved. Period.

You need someone on your side to protect you. You'll need to deal with the neighbor and the association.

Or as previously mentioned, the backyard.

Is there a backyard space? There's no reason the compressor *needs* to go on the roof. Avoiding the situation may be best.

Honestly, you and your neighbor together should go down to 30 Montgomery 4th floor and have a list of questions ready.
Good luck.

We own the top floor of a small brownstone building, and the roof is deeded to us - we have the right to build a deck there (with condo assoc approval). Currently, there's nothing on the roof, and it is 100% maintained by the condo assoc.

A downstairs neighbor is looking into installing ductless AC and may need to put a compressor on the roof - which is deeded to us.

This is new to us, and we're wondering if anyone can provide insight into a situation like this?

- Any reasons for allowing this (besides good neighbor relations)?

- Any reasons to not allow this?

- Pitfalls?

- if we allow this, what do we need (and ask for from the neighbor) to make sure we are protected - from a legal and monetary perspective?

We assume we will need to get a lawyer to get all responsibilities written down on paper, and signed if we go ahead with the neighbor?

Thank you in advance for any feedback!

PS also want to note that we may, or may not, also install a separate ductless AC unit along with the neighbor. We are in the "exploratory" stage and just got a contractor here for the initial visit together. Still haven't decided if it is a "go" for us or not.