Boiler Power

Boiler Power

At first glance, “horsepower” may seem like an odd way to calculate and compare the output of a boiler. It’s not like anyone is racing boilers up and down the dragstrip. However, much like the horsepower of an engine, the horsepower of a boiler is a measure of just how much power it puts out. This power translates to the amount of work that the end processes will be able to accomplish. Obviously, the higher the horsepower, the more powerful the boiler, but what does it mean, exactly?


The term “horsepower” was first coined by inventor James Watt in the 1800s as a way to compare the work that a steam engine could do versus the work that a horse could do. Remember, back then, a lot of mechanical processes like grinding grain, moving coal, pumping water, and plowing fields were done by actual teams of horses. By classifying steam engine output in terms of horsepower, then, it gave customers a rough idea of how much they could accomplish with a steam engine, and how many horses it could eventually replace in the processes happening in farms and factories. 


The official definition of one horsepower in the boiler industry is the amount of energy it takes to evaporate 34.5 pounds of water into steam in one hour at a temperature of 212 degrees Fahrenheit. One horsepower also translates to 33,475 British Thermal Units per hour, if you’re keeping track. Basically, it all comes down to heat energy and how it converts into work. Boiler horsepower and British Thermal Units are simply two different ways to measure the amount of heat energy that is transferred by the boiler, corresponding to a specific amount of work that can be done as that heat energy is turned into mechanical energy at the end process. 

Another way to think about boiler horsepower has to do with one of steam’s most popular uses: electrical generation. Steam is used to power the turbines that keep the lights on around the world, and in the world of electricity, one boiler horsepower equals 9.81 kilowatts of energy. That can give you some idea of how it all relates together. Since the average American household uses about 11,000 kilowatts of energy per year, it would take roughly 1121 boiler horsepower to keep one home running for one year. That means that just one of WARE’s larger boilers could produce all the energy a home would need for a year in about 30 minutes.  

No matter how big a boiler you’re running, WARE is here to help you keep it running better. If your boiler is at the end of its useful life, consider a new boiler from our extensive fleet to upgrade your efficiency, and if needed, your steam capacity. And if you’d like to learn even more about boilers, horsepower, and the intricacies of steam production, there’s no better resource than WARE’s Boiler University. We have classes online and in-person. Of course, if you need service or maintenance, we have highly trained technicians who can do whatever you need. Remember, we’re here to help.

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