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When examining commercial HVAC equipment, the amount of information that comes flying at you can be overwhelming. There’s no shortage of numbers and jargon, and all of it seems to add up to be very confusing indeed. When all you want is an easy and affordable way to heat or cool your business, office building, or other commercial space, untangling all this information might be the last thing you want to do. However, it is necessary — otherwise, you’ll run the risk of making a choice that isn’t effective at providing heating and cooling for your employees. One of the terms you will encounter frequently is “BTU.” What is that, and what does it mean for your business? Understanding the BTU and its definition is essential for making smart choices further down the pipeline when you begin looking at actual HVAC units on a regular basis. 

The BTU: A Definition

Technician holding report and pen while standing in front of equipment BTU stands for British thermal unit, though we haven’t always called it that. In the 1800s, it was simply known as a “heat unit.” Fun fact: no one really knows where the unit came from initially. Today, though, we’ve given it a standard definition to reduce confusion and make it easier to create equipment that conforms to the same specifications. That definition is as follows: one British thermal unit is equal to the amount of heat necessary to make one pound of water hotter by one degree. For the average home or business owner, though, that definition doesn’t mean much. What’s the big deal?

When you see an air conditioner or a furnace with a BTU rating, you’re likely going to see a very large number. That doesn’t mean the unit is actually pumping out tens of thousands of BTUs of heat — that wouldn’t be good for your home at all. Instead, the number you’re seeing is the number of BTUs per hour the unit can remove from a specific space. Sometimes instead of BTUs, you may see “tons” instead; we’ll touch on that later. What’s important to know, however, is that the higher a unit’s BTU rating, the more powerful it is. 

Where Did This Weird Term Come From, Anyway?

As mentioned, the history of the BTU is a little murky; its exact origins remain unknown. We only know about work that later individuals did to address concerns about how to measure heat as a quantity. After all, it’s easy to say how hot a fire is in terms of its temperature, but not so easy at all to explain how much heat it gives off over an hour. The closest we can come to discovering the origin of the BTU lies with a man from the 1800s named Thomas Tredgold. A railroad engineer, Tredgold worked on identifying a way to explain the heat contents of various fuels. The standard he developed is very similar to the one we use today, correlating heat output to how much energy it takes to warm a certain amount of water. We’ve used something similar ever since.

Why British thermal unit, though? As it turns out, there was once a competing French thermal unit, developed around the same time in the mid-1800s. However, that unit never caught on and quickly fell out of use. Americans across the pond soon adopted the measurement, dubbing it the British thermal unit, or BTU for short. Today, America remains one of the only countries to use the BTU as a regular measurement. 

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What Are Tons of Cooling, and How Do They Relate?

While residential air conditioners often express capacities in terms of BTU/h, big commercial units such as you’ll encounter require use to use the BTU for another definition. This time, it’s a ton of cooling. We don’t mean that figuratively, but rather literally: a “ton of cooling” refers to the number of BTUs necessary to freeze one ton of water in one day. That translates to about 12,000 BTUs per hour. For commercial business owners, you will want to take care when calculating the load requirements for your building. An HVAC unit without the right tonnage could result in energy inefficiencies or improper cooling. Appropriate sizing is essential. 

Keep BTUs in Mind When You Explore Options for Commercial HVAC

Worrying about “British thermal units” might not be what you had in mind when you began exploring options for commercial HVAC units, but knowing the BTU definition will help you to understand other aspects, such as cooling tonnages. With this knowledge, you can demystify some of the jargon you’ll encounter during the buying process and stay better informed. In the end, this should enable you to make good choices about the equipment you purchase. What if you don’t know the heating or cooling needs of the space you have, though? Don’t try to figure out how to calculate the necessary BTUs all on your own — contact an HVAC contractor you can trust instead. With help from the pros, you’ll be on your way to an excellent installation in no time.