The difference between modern and old air conditioners and furnaces is huge and is worth talking about.
When I was a kid, I loved learning about the early stages of technology, specifically in the world of HVAC.
I learned about the first window air conditioner that was made from only a few different parts. Then I learned about the wood furnace that was huge in its day. After that I learned about central air conditioners and gas, oil, and electric furnaces. A little later air purifiers became a big deal and every heating and cooling business wanted to get them on their shelves. I loved learning about all of these things. Now that I am older, I enjoy working on a/c units and furnaces and building them myself. I also work as an HVAC technician on the side for extra money. All this to say, I know a lot about both modern and old HVAC units, and I wanted to take a minute to compare them. Many people think that technology has advanced so much over the years that an old air conditioner or furnace would be unrecognizable to the modern eye. This simply is not true. The truth is, old window air conditioners were structured much like modern window air conditioners, just with simpler internal parts. Old window air conditioners did not, however, have any air filters which does make a big difference in how well they work. Back in the day, central air conditioners were not really heard of except for in some of the more wealthy homes. Back then, commercial air conditioners were more of what many normal households have as their central air conditioners.