There are >30 million window air conditioners in the US today. They whir all summer, drip water and hang precariously on window ledges. But as unappealing as they may seem, they have played a pivotal role in energizing life as we know it and shaping the structure of the grid. Here’s how.

What’s in a name? In 1906, more than twenty years before the window AC was invented, the same technology was applied to control humidity in manufacturing processes. Because of this legacy, we still call it an “air conditioner”, instead of an “air cooler”.

A blockbuster bet is made in 1911. Films were a popular pastime at this time, and theaters made lots of money, except when the weather got too hot. Then… No. One. Went. So movie theaters did what any savvy, risk-tolerant business would do. They invested in air-conditioning ahead of everyone else, so that they became THE cool spot in town. A theater in Montgomery Alabama got the very first one installed in 1911, and theaters throughout the country followed suit. Now people flocked to see movies to stay cool in the summertime, instead of avoiding them.

This is what started the summer blockbuster movie phenomenon!

1931 gives rise to the window AC. Two guys – Schultz and Sherman – filed a patent for an air conditioner that could sit on a window ledge in 1931. The ingenuity involved in shrinking ACs down to a window ledge footprint was impressive. By comparison, the first home air conditioner that was installed just 16 years earlier was the size of a bedroom (6 feet wide by 20 feet deep and 7 feet tall).

Within a year, the first window AC units were available for sale for $10,000-$15,000. That’s $120,000 to $600,000 in today’s dollars, so only the super wealthy could afford them then.

The grid responds in 1942. In 1942, the US built its first peaking power plant to handle the anticipated spike in daytime electricity use coming in large part from window ACs. Peaker plants are power generation plants that are only turned on when people use more electricity, to ensure that there is enough power to go around.
And was it the right decision at the right time! By 1946, demand for window ACs shot up, and more than 30,000 units were made that year. A bigger milestone was reached in 1953, when over 1 million units were sold in one year. Companies installed them to boost worker productivity, and homes got them as a symbol of post-war boom.

Window ACs go WiFi. Fast forward to today, and even the window AC has gone IoT (internet of things). Now consumers can turn their window ACs on from a smartphone and better control their energy use, enabling all of us to see that we can have a two-way relationship with energy, and the productivity and comfort that it provides us with.

How cool is that? Off the ledge cool.