Climax Ad from 1891
I love John Perlin’s style. His historical review of bathing habits gave me a chuckle. It was the 19th century, he writes, that Americans and Europeans began to bathe on a regular basis. Heightened sense of personal hygiene was taking root. But heating water was laborious; that’s why you just took one bath a week. It was an ordeal heating large pots on stoves, then carrying heavy pales of steaming hot water to “bath room.” An important step was to attach hot water tanks to cook stoves.
The first solar water collectors were developed by farmers in the American Midwest. They painted metal tanks black, mounted them on rooftops, connected them to their water systems, and enjoyed hot showers after working the fields. The systems worked, but when they worked and for how long they provided hot water were other important questions. Without insulated storage these systems were of limited utility.
The first commercially available systems – the Climax solar water heater in 1891 – used tanks in glass-covered boxes that retained heat after sunset. In Maryland, the Climax produced hot water from April to October. In many parts of California, it produced free hot water year-round. By 1900, the Climax had sold 1,600 units. Then in 1909 came the “Day and Night” solar water heater which had two tanks, one for solar collection and the other insulated with powdered limestone for storage. The tanks were guaranteed not to lose more than a degree per hour. A later development was replacing the collector tanks with thin copper pipes which greatly increased absorption.
In January 1913, a freak cold spell hit Southern California and the solar water heating industry was badly hurt. Temperatures dropped as low as 10 degrees F. Collectors froze and copper pipes “popped like popcorn all over the county.” This led to the development of collector circulation systems that have heating loops filled with alcohol and distilled water to prevent freezing. Using heat exchangers in the form of coils, heat can be transferred from one medium to potable water.
With freezing addressed, the solar water heating business began to flourish again. Popular Mechanics ran a do-it-yourself article on building solar water heaters. It was in vogue and advertisements doled out the virtues of solar, reducing natural gas bills. In 1920, 1,000 people bought Day and Night solar systems. But between 1920 and 1930 huge amounts of natural gas was found in the Los Angeles basin, and prices plummeted, slashed by 75% for consumers. Wherever the gas mains went, consumers jumped on board, and interest in solar plummeted.
The action shifted to Florida where there was no natural gas and it’s difficult to lay pipes in subsurface marshland. Many bungalows in Miami began to have solar systems. The residential building boom there was a boom for solar. The Solar Water Heater Company was the dominant company, and given sloping roofs put tanks cut into roofs disguised as chimneys. An advertisement in 1941 spells out a no-money-down financing option and low monthly payments.
World War 2 dealt a blow to the U.S. solar water heating industry given a government freeze on non-military use of copper. Then older systems began to fail, typically at 2:00 in the morning when municipal water use is lowest and thus pressure is highest. Solar was also getting more costly, given higher copper prices and labor costs. Meanwhile, electric water heaters were getting less expensive. Florida Power and Light, for one, adjusted its rates to favor electric water heating, and even offered free installations of electric water heaters. By the late 1950s, no one was buying solar water heating in America.
Instead, the action shifted around the globe to areas where solar water heating makes most sense. It’s an appropriate technology for fuel-short regions like South Africa. In the 1950s, “vinyl air mattress” solar water heater was introduced by Sukeo Yamamoto in Japan. It was low cost and highly effective. Australia took a leadership role promoting solar water heating. Solar was also advancing in remote areas remote locations such as the Canary Islands.
Israel became and has remained a leader in solar thermal. Nearly 50,000 solar water heaters were sold in Israel from 1957 to 1967. Ironically, the victory in the Six Day War of June 1967 dealt a blow to solar when Israel captured large oil fields on the Sinai Peninsula ending decades of fuel scarcity.