Refrigerators and air conditioning were both considered essential home appliances in North America during the 20th century.
Refrigerators: Refrigerators started to become more commonly used in households in the early 20th century. However, they were initially quite expensive and limited to wealthier families. The major breakthrough came in the 1930s when the introduction of Freon, a safe and effective refrigerant, made refrigerators safer and more affordable. By the 1940s and 1950s, refrigerator ownership had become more widespread in North America, and it became a standard appliance in most homes.
Air Conditioning: Air conditioning also emerged in the early 20th century. The concept of artificially cooling indoor air dates back to ancient civilizations, but modern air conditioning as we know it today began to develop in the early 1900s. The first electrically-powered air conditioning system was invented by Willis Carrier in 1902, primarily to control humidity in a printing plant. Over time, air conditioning technology improved, but it remained relatively expensive and was initially used primarily in commercial and industrial settings.
Air conditioning started becoming available to the general public in North America during the 1920s and 1930s. Movie theaters, department stores, and luxury hotels were among the first public places to adopt air conditioning. It wasn't until the post-World War II economic boom in the 1950s and 1960s that residential air conditioning became more widespread and affordable. As temperatures rose during the hot summer months, air conditioning became increasingly popular for homes across North America.
Overall, both refrigerators and air conditioning became essential home appliances in North America during the mid-20th century, and they have since become standard features in households across the region.