I've got a 6000BTU GE fashionette in my workshop shed that is at least 30 years old. It uses R12 refrigerant, spine fin coils, and gets 38 degree duct temperatures during the summer...great running little unit! I'll hafta take a picture of it and post it sometime. The previous owners left it in the shed. It had all sorts of crud clogging the coils and wouldn't work at all when I moved in. After disassembling it and cleaning out all the leaves, dirt, bugs, etc, it worked like brand new!
My Brother in law has a big 24,000 BTU Sears Coldspot window unit that's not in use anymore. It dates back to about 1958 or so as much as I can tell. The unit origionally was used to cool the rescue squad building my parents belonged to. When they installed central air in the squad building in the early 80's, they gave it to my parents. It resided in our dining room window for the next 8 years or so till Mom & Dad bought a central air system. That was also about the time my sister & brother in law got married, so it was sort of a wedding present for their new home which didn't have air conditioning. They used it for another 10 years or so till they had kids and moved into a bigger home with central air. He's keeping it to install in his garage once it's built. The unit has been around, but everyone loves it because it puts out such cold air! The thing about it is that it is HEAVY and is a real power hog!
Now, the last story involves the GE zone-lines that my grandparents put in their new (in 59) home. I think I posted that story a good while ago. Too bad the house isn't in the family anymore, but I noticed those air conditioner / heat pumps still hum away when I've been by the house. These units were nice because of their unique grille arrangement. The front was a complete metal panel that sat away from the wall about 4 inches or so. The cool air was discharged out the top, and it was drawn in at the bottom. My grandmother had wall-papered the cover to match the rest of the walls in the bedroom, and upon casually looking into the room, you wouldn't notice the air conditioner under the window! Only one had been replaced, and that was the one in the rear family room, and I imagine that was because it got the most use.