I used Allied Aire for my AC install (I wish I used them for my furnace... but that's a different story). They're located in Milpitas, but they came out to my place (S. Los Altos Hills) with no problem. Their rates were reasonable and they did a good job; I'm sure they do furnaces as well.
They do have a website, which I think is www.alliedaire.com
(this is my first post btw... good luck with your search)
-G
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