I live in San Francisco, and have ducted air central heating.
I don't need AC that often, but sometimes it would be great.
I'm in the second floor of a 2 unit condo, and have no outside space except a deck.
The furnace is in the garage - is it possible to install a condensor unit in a garage that has an outside wall?
If so is it possible to get a really quiet one so that it doesn't keep my neighbors awake whose bedroom is next door?
There are several brands of through the wall units such as this http://securenet.goodmanmfg.com/pdf/...Lit/ss-343.pdf on the market that might work for you.
the condensor could go on the roof.
You might look into putting a small condenser on the patio. Some of the small ductless type units that are horizontal discharge are very quiet.