When I was younger, I had no idea there was such a thing as building codes. Even today, as an adult, I do not know exactly who decides what the building codes should be, and I am not even certain when you have to apply for permits and consult the building codes manual. I do know, however, that in my city, the building codes require that every edifice being built must have some sort of HVAC system. Whether it is central air conditioning or a heat pump and cooling system or a mini split ductless air conditioner, there must be some kind of heating and cooling system in the design of the building. I could not imagine living or working in a building without a heating and cooling system, especially since I live in the south where people pass out from excessive heat. But I do know that it has not always been a requirement. Nowadays, though, many buildings do not even have windows that open, so without a great HVAC system, good indoor air quality would really be an impossibility. When I was quite young, I had an aunt and uncle who no air conditioning in their house, and even back then I thought it was weird. They used box fans, not even ceiling fans. Now, I have ceiling fans in every room in my house. They don’t really cool the air like an air conditioner does, but they make you feel cooler. So, I guess the building code makers know what they are doing as far as HVAC systems are concerned.