The difference between new plus ancient A/Cs plus oil furnaces is sizable plus is worth talking about. When I was a kid, I enjoyed learning about the early stages of technology, certainly in the world of Heating plus A/C. I l acquired about the first window A/C that was made from only a few strange parts. Then I l acquired about the wood oil furnace that was sizable in its morning. After that I l acquired about central A/Cs plus gas, oil, plus electric oil furnaces. A little later whole-house air purifiers became a giant deal plus every heating plus cooling supplier wanted to get them on their shelves. I enjoyed learning about all of these things. Now that I am older, I enjoy laboring on a/c units plus oil furnaces plus building them myself. I also work as an Heating plus A/C specialist on the side for extra currency. All this to say, I guess a lot about both new plus ancient Heating plus A/C units, plus I wanted to take a hour to compare themâ€¦ Many people feel that technology has advanced so much over the years that an ancient A/C or oil furnace would be ununique to the new eye. This simply is not true. The truth is, ancient window A/Cs were structured much love new window A/Cs, just with easyr internal parts. Old window A/Cs did not, but, have any air filters which does make a giant difference in how well they work. Back in the morning, central A/Cs were not truly heard of except for in some of the more wealthy homes. Back then, commercial A/Cs were more of what many normal households have as their central A/Cs.