Direct vs. Indirect Fired Heaters

Direct vs. Indirect Fired Heaters

Fired heaters are highly cost-efficient, making them an excellent option for your heating needs. Fired heaters consist of an insulated closure that uses fuel combustion to heat commercial buildings, but not every fired heater is built with equal heating capabilities or safety parameters. That's why you'll want to consider these differences between direct and indirect fired heaters when you're choosing a heating solution.

When Should You Get a Direct Fired Heater?

Direct fired heaters are the most efficient and cost-effective type of fired heater, but they come with potential safety concerns. Direct fired heaters are powered by natural gas or propane and create an open flame that heats your industrial or commercial space. They require a tricky balancing of air-to-fuel ratio and feed their gas straight through a burner with the combustion power of oxygen. Direct fired heaters emit warmth parallel to the airflow of a space. 

Direct fired heaters come with the following advantages: 

  • Simplicity and size: Direct fired heaters don't require a heat exchanger or flue like indirect fired heaters, which makes them much easier to install. They can also produce more heat in a smaller amount of space. 
  • Efficiency: Unlike other methods of heating, direct fired heaters can convert almost 100% of the fuel they use into heat. Every direct fired heater has a thermal efficiency of 92% and a combustion efficiency of 100%.
  • Flexibility: Direct fired heaters can be designed in a variety of sizes to achieve your desired BTU rating, letting you find the perfect fit for the space you're heating.
  • Durability: Due to their construction, direct fired heaters last longer than the competition. 

When Should You Get an Indirect Fired Heater?

Unlike direct fired heaters, indirect fired heaters fire their burner into a heat exchange that allows the byproducts from combustion to remain in the exchanger and get exhausted through the flue. More complex indirect fired heaters may also be outfitted with energy recovery and cooling functions. Indirect fired heaters come with the following advantages: 

  • Safety: Indirect fired heaters are the safest type of workplace heater and release no combustion products into the air. This design makes them ideal for commercial spaces such as offices, sporting arenas, schools and medical facilities. 
  • Cooling coils: With indirect fired heaters, the air in the system does not pass directly through an open flame, but goes downstream of a DX cooling coil. This process removes the risks associated with refrigerants and prevents the formation of toxic gases inside locations with poor ventilation. 
  • Reheating ability: Indirect fired heaters allow 100% of the air to be recirculated without releasing combustion byproducts into the airstream.  

Request Fired Heaters From The Cat® Rental Store

At The Cat® Rental Store, we have the direct and indirect fired heaters you need to meet the specific demands of your facility or job site. Our dealers carry OEM products from more than 70 top brands, and every single piece of equipment we rent meets our high standards of reliability and durability. To learn more about our fired heaters, browse our selection and get a free quote online or at 1-800-RENT-CAT.

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