From the History of air-conditioning

In the 1920s air-conditioning for comfort was first used when motion picture industry was building theatres in the U.S. All of the Movie Palaces of those years hung out huge sings proclaiming that it was 20 cooler inside and, while admittedly some of the installations were far from perfect by today standards they served to introduce the public to air- conditioning.

While a few residences were air- conditioned prior to World War 2, home air - conditioning did not really start growing until some 10 years after the war. The early residential air- conditioners were expensive, were really a luxury then, installed only in the most expensive houses.

Today, the number of centrally air - conditioned homes is growing from year to year at an accelerating pace in addition to homes that are centrally air conditioned; there exist window air - conditioners in one or more rooms. Complete data are not available on the penetration of air -conditioning in industrial plants, but it is known that only a small percentage of them are air - conditioned. Schools and hospitals are now also moving into air -conditioning and most of them are being designed for air -conditioning, ft has already been proved that air - conditioning is a "must" in hospitals and all new hospitals being built today are air -condi­tioned. At the same time, all stores, restaurants and other retail establish­ments arc being air- conditioned. Aside from the creation of comfort con­ditions, numerous studies have determined that air- conditioning adds to human efficiency. Air -conditioning cuts the costs of products, steps up production. Many of the new industries of our present era and many new developments within all the types of industry could not have existed in a non- air - conditioned age.

4. Answer the question: «Where is air - conditioning used?». Give the examples from the text to illustrate your answer.