BTUs - Measuring Energy the HVAC Way

Someone is pouring tea from a teapot into a white cup on a saucer.

There are lots of means for measuring energy. With food, there are calories. With electricity, we have the kilowatt/hour. In combustion, there’s the Tonne of Oil Equivalent, which you can tell by the spelling is a very European classification. Measuring energy in “tonnes” is probably a unit based on how many elves it takes to produce the energy equivalent of one barrel of oil.

And then, speaking of Europe, here comes the BTU, or British Thermal Unit. We aren’t sure why the British were allowed to name another thing after themselves. They already have a muffin and a language, and they pretty much have the corner on BBC news and breakfast tea. Do they really need to stake claim to measuring energy as well? Nevertheless, BTUs are the go-to for measuring energy as it pertains to heat.

Here’s our best, simplest explanation for how BTUs are figured and how they affect you:

  1. One BTU is equal to the amount of energy it takes to raise or lower a pound of water one degree Fahrenheit at sea level. We know that sounds unnecessarily arbitrary and convoluted, but, hey, these are the same people who created Monty Python and cricket. So if we say a house needs 18,000 BTUs of heat per hour, that’s the same amount as if you wanted to heat 18,000 pounds of water one degree. If you’re lost, don’t worry. Let’s look at what that means for heating a home.

  2. To find out how many BTUs it will take to heat or cool your home, take the square footage and multiply it by 20. A 2,500 sq. ft. home, for example, requires 50,000 BTUs. Lots of variables can toy with that figure - like the number of windows, doors, or cohabitants you have, and even things like climate, lifestyle, shading, home design, and how warm natured your people are. (To play with a BTU conversion calculator, click here.) Jake’s Heating & Cooling will walk you through this process, no worries!

  3. The next step is to figure out what size of HVAC system you need. To do this, take the BTU number you just found and divide it by 12,000. So the 50,000 BTU need that we figured (divided by 12,000) will require a furnace or air conditioner with a size of 4+. That’s the “tonnage,” which is a unit that measures how many BTUs the system cools or heats in an hour. Since that 12,000 factor is based on a best case scenario, HVAC companies often recommend erring on the larger side. For example, having 9ft ceilings instead of 8ft ceilings can make a huge difference in the number of BTUs it will take to heat or cool the home, even though the square footage is the same.

BTUs are a helpful means for measuring energy, but there’s so much more that goes into what really matters - keeping you and your loved ones safe and comfortable. Jake’s Heating & Cooling will assess your specific needs and variables and come up with a plan that includes more than the size of the HVAC system. We will use our many years of successful service and knowledge to ensure you are matched up with exactly what you need and want. Contact us and we’ll make a plan together!

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