What is BTU Rating?



When your commercial garage, warehouse, or equipment building is cold, workers aren't safe. They're less focused on their tasks, are more likely to suffer injuries, and are less responsive. Keeping the space warm with a space heater can mitigate these concerns without all the costs of installing permanent furnaces and heating systems. Portable heaters can even provide mobile, well-directed heat where you need it in field locations and temporary buildings. If you're shopping for a commercial-grade space heater, understanding what BTUs you're looking for is essential. In this guide, we cover everything you need to know about BTUs and how to determine what rating you need.

What is BTU Rating

What is BTU Rating?

BTUs are used to measure the heat energy generated by various objects. This unit standards for "British Thermal Unit," but it is commonly used across the United States. A single BTU is the amount of heat energy required to make one pound of water increase its temperature by one degree Fahrenheit. The comparable SI unit for BTUs is joules, which 1,055 joules being equal to one BTU.

BTUs are used to denote the energy value in several different contexts, ranging from the amount of artificial heat generated and put out by heaters to being used in displaying the price of natural gas. In the context of heaters, a BTU rating establishes both the amount of heat it can output and how much energy it consumes in order to provide that heat. Conversely, air conditioning units (which cool by removing heat) are also rated in terms of how many BTUs of heat it removes during an hour of operation.

Why Do You Need to Know a Heater's BTU Rating?

If you purchase a space heater for your warehouse, your commercial garage, or even a workspace at home, it's important to know how much heat you can expect to receive and how "expensive" that heat will be in terms of energy consumed. You can locate a unit's BTU rating on its specifications sheet to compare different units, find the best option for your space, and anticipate the amount of power it will have.

The higher the BTU rating is, the more heat energy it can generate. That means higher-rated units can either heat up bigger spaces or heat up small spaces faster.

BTUs and Efficiency

BTUs measure power, but you need a separate efficiency percentage to know how efficient a heating unit is as a whole. Manufacturers measure the efficiency of heaters based on their operation at the highest possible setting. They calculate the efficiency percentages by dividing the hourly output BTUs by the input BTUs and then multiplying the total by 100.

For example, if a space heater outputs 72,000 BTU but has an 80,000 BTU input rating, it has a 90% efficiency rating. Another unit may have an 85,000 BTU input rating but still only outputs 72,000 BTU, it will have an efficiency rating of 84.7%, making it more wasteful.

Pro Tip:

Remember, manufacturers base the efficiency on how units behave when they're at the highest setting. So if you operate your unit on a lower setting, that will reduce its operational efficiency. That's why it's important to choose a unit with the right power based on the dimensions of the space that needs to be heated instead of selecting the most powerful or efficient unit.

How Many BTUs Do You Need?

As you start shopping around for a space heater for your commercial garage or workspace, one of the most important factors to consider is its size. The "size" isn't about the physical dimensions of the unit; it's the colloquial term for the amount of BTUs a unit generates. 

Choosing the right size is just as important when you're investing in cooling systems and portable air conditioning units. If you select a unit that's too small for a given space and the amount of air it needs to condition, the unit will be constantly running at full power without ever reaching equilibrium. This can be very costly. However, over-powered units that are too big for a space can also be costly because you're overpaying for the unit and constantly running it at a setting that isn't the most efficient.

But how do you know what the right-size unit is for your space?

First, you need to know how much air is in the room or open building you want to heat (or cool). You can determine this by calculating the square footage of the space (length multiplied by width). Then refer to a BTU chart to find the corresponding BTU rating for that approximately-size space. 

There are a few factors that can complicate this calculation, however. These factors include:

  • The height of the ceiling: Commercial garages, barns, and other spaces can have very high ceilings, much higher than the typical eight- or ten-foot ceilings in residential spaces. Because hot air rises, you'll need more power than you may expect to heat up the space enough for warm air to stay in practical workspaces.
  • Thermal mass: If you're heating up a space packed with inventory or machinery, your heat needs will fluctuate. Objects have thermal mass, allowing them to hold onto heat (or a relative lack of heat). As you heat a cold room, bulky objects will absorb heat, making the room slower to warm up. However, those objects will also hold heat longer than air, so keeping the space at a pleasantly warm temperature will be easier than bringing it up to heat in the first place.
  • The environment: Cold environments, buildings with poor insulation, and buildings with wide-open doors will all force a space heater to work hard in order to keep the space comfortably warm. These factors allow the heat to "escape" quickly.

Look for helpful BTU charts that take these factors into consideration or space heaters built specifically for spaces similar to yours to avoid these confounding variables.

Contact NorTex Sales & Service Today

At NorTex Sales & Service, we specialize in providing high-quality tools and machinery for our clients. Our high-performance space heaters are built to provide reliable, efficient heat. We also provide units built to direct heat at your practical workspace for faster functional warmth. We serve clients from our three Texas locations so we can ensure fast delivery and service season after season. Contact us today to learn more about our inventory or to place your order.

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