If you’re considering a new furnace or water heater, you may have seen the term “BTU.” But what is a BTU and how does it apply to your HVAC system?

BTU stands for “British Thermal Unit,” and it’s how heat output is measured. One BTU is equal to the heat generated by burning one match. BTUs are measured according to how much heat it takes to increase a pound of water by 1 degree Fahrenheit.

That’s confusing, isn’t it?

It also indicates how much energy a fuel produces, such as propane, electricity, or even wood.

Let’s do a quick deep dive to make this a bit clearer.

How Does the BTU Rating Apply to Your HVAC System?

As a homeowner, you want to understand how to best choose your HVAC equipment. You want to avoid common pitfalls. One common mistake many homeowners make is buying the wrong size equipment for their house.

Heating BTUs

With furnaces and heat pumps, you’ll see two different BTU ratings. One number will be the BTUs for the energy consumed when running. The other number will show you how much heat the equipment can generate.

Cooling BTUs

For air conditioners, the BTU rating shows you how much energy your unit uses during an hour of run time. It also shows how much heat it removes from your home.

Every 12,000 BTUs of cooling equals “one ton,” and you’ll often see central AC units measured in “tons.”

With these numbers, you can get a good idea of how efficient the equipment and whether it’s the right size for your home.

Why Do I Need to Understand BTUs?

HVAC equipment needs to be “sized” correctly to distribute an even amount of heated or cooled air throughout your entire home. In this case, the “size” is the size of your home, not the size of the actual equipment.

Are Higher BTUs Better or Worse?

Higher and lower BTUs are less important than the right BTUs for your home.

For example, a window AC unit requires 20 BTUs per square foot to adequately cool a room.

Your furnace, however, is sized according to where you live and the square footage of your home. Here in Pennsylvania, for example, you’ll need 40 to 50 BTUs per square foot.

Too many BTUs means your equipment will run for a shorter amount of time, rather than working steadily to keep the space comfortable.

Too few BTUs means the equipment will run constantly, unable to reach the setting temperature on the thermostat.

How to Figure BTUs

When it comes to expensive HVAC equipment, you must pay heed to a wide range of variables that effect the comfort of your home. You also need to consider ceiling height, number of doors and windows, facing direction, and more.

Make an appointment with the HVAC professionals at One Hour Heating & Air Conditioning in Bethel Park. We can calculate and install the best HVAC equipment for your home’s unique requirements.