If you are buying a car and have no experience measuring power or vehicle statistics, one of the key features of a vehicle can be confusing – its horsepower.
If some cars have over a thousand, how many horsepower can one horse produce and how did this concept come about?
Horsepower as a marketing tool
The maximum horsepower is actually much closer to 15 horsepower. In fact, a more appropriate name for this unit of measure could be “human power”, given that the average healthy person can produce just over 1 horsepower.
So where did that expression come from then? It was first invented in the late 1700s by James Watt, a Scottish engineer remembered for his cult and incredibly efficient steam engines. Looking for a way to advertise his inventions, he invented a unit of measurement that effectively demonstrated the superiority of his steam engines over what humans know – horses.
Watt discovered, by personal observation, not by controlled scientific research, that a working horse could spin a grinding wheel 144 times an hour. Using this figure, he estimated that the horses were able to push about 14,774.41 kilograms in length of 1 meter per minute. For convenience, he rounded this to 14,968.55 kilograms of work per minute and the horsepower unit was born.
He did not care much about the accuracy of the measurements, but about a term that highlights the drastic productivity improvements that customers would experience if they bought one of its steam engines. His machines were indeed much more powerful and reliable than horses, and as a result, very few people doubted or cared about the veracity of his calculations.
Watt was undoubtedly an engineering genius, but also a marketing genius, and his contemporaries valued him so much that, in recognition of his pioneering work and endeavors, the watt power unit was finally named after him in 1882.
Given that we now know that a horse can produce much more than one horsepower, why are we still using the term that Watt coined as part of a marketing campaign? Because it has taken root in the language and has acquired a meaning that does not depend on factual assessment and the accuracy of its origin.