Living in a world without HVAC units is as sad as living somewhere without water.
I was sent to a different dimension through a portal into a world where nowone knows what an air conditioner or furnace is. The people in this world solely live on natural heating and cooling. Instead of figuring out how to build a central air conditioning unit, they just build their houses in the caves where it is always cool. The biggest problem with this is that the cool caves can’t be turned up or down like an a/c unit can. Some days it is too cold, and other days it is not quite cool enough. In the winter time, instead of developing a portable space heater or a gas furnace, these people rely solely on fire to keep them warm. There are no zone controlled heating systems like there are in our world that are able to make one room warm and another hot. In this world you are either too warm or too cool. I tried to introduce a simple portable space heater, but the people just couldn’t seem to understand. I then had a goal. I was going to make a window air conditioner for every home in my neighborhood and see if the people would accept it. I am a very experienced cooling expert, so I knew how to build a window air conditioner that was very good quality. Even though I am an HVAC technician, it still took me several months to finish all of the window air conditioners for all of my neighbors.