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What Is a Fan Trench Heater?

Posted by Chris Burroughs on July 8, 2025 at 9:00 AM
Chris Burroughs
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Fan trench heaters are specialized heating devices that are embedded within a trench in the floor or mounted in a low-profile enclosure at floor level, typically along the perimeter of a room or under windows. This type of heater combines a heating element, such as a multipass water coil or electric resistance heater, with a fan to enhance air circulation and heat distribution.

Fan trench heater mounted in a low-profile enclosure Fan trench heater mounted in a low-profile enclosure
Fan trench heaters are embedded within a trench in the floor or mounted in a low-profile enclosure as seen above
 

How Do Fan Trench Heaters Work?

Fan trench heaters draw in cool air at floor level, which then passes through the heating element. The fan (often powered by 24 VDC) assists in circulating the warmer air back into the room, ensuring even heat distribution and eliminating cold spots. This process is particularly effective at reducing cold downdrafts from windows and maintaining comfortable indoor temperatures, especially in areas that contain tall perimeter glass.

Linear Fan Terminal Cross-section of Linear Fan Terminal with pedestal support
 Price’s Linear Fan Terminal (left), with a cutaway view with pedestal support (right)

Hydronic cooling versions, also called trench convectors, are available in a noncondensing version, where the entering water temperature is above the space’s dew point, and in a condensing style with drain pans.

Why Are They Used?

Fan trench heaters offer several advantages.

Space-Saving Design

Since fan trench heaters are typically installed flush with the floor, they maximize usable space and maintain unobstructed views. The fan pulls in room air, so no ductwork is needed, and only small hydronic piping is installed to distribute the heating or cooling into the space.

Energy Efficiency

Trench heaters deliver heat directly to the occupied zone, thereby minimizing losses in the distribution of energy. Warm air naturally wants to rise, and trench heaters take advantage of this effect. The fan boosts output through the heat exchanger and can use lower-temperature heating equipment such as heat pumps and condensing boilers, which can lead to significant energy savings.

Whisper-Quiet Operation

Fan trench heaters operate using a low-wattage tangential cross-flow fan, enhancing comfort without the noise disturbances that come from fan start-up, duct pressurization and other relays.

Discreet Appearance

Their low-profile design allows them to blend seamlessly into the surroundings using a variety of floor grille styles, such as linear bar grilles or roll-up grilles, with finish options ranging from anodized or painted aluminum to stainless steel.

Linear Bar Grille
Roll-Up Floor Grille
Fan trench heaters blend seamlessly into a space with the help of floor grilles such as Price’s Linear Bar Grilles (top) and Roll-Up Floor Grilles (bottom)

Comfort

Fan trench heaters, by design, are decoupled from the central system and allow tighter control of the output and airflow directly into the space, creating a comfortable indoor environment for occupants.

Where Are They Typically Installed?

Because of their vast design options, fan trench heaters are ideal for a variety of applications:

  • Lobby areas
  • Residential buildings
  • Educational facilities
  • Airports
  • Spaces in the hospitality industry, such as hotel rooms
  • Commercial office buildings
  • Institutional and government facilities, such as municipal buildings, military facilities, museums and historical buildings

Fan trench heaters play a pivotal role in modern heating solutions, and the benefits of this technology are manifold. They offer energy efficiency, space-saving designs and quiet operation, enhancing both the comfort and aesthetics of a space. And by supporting decarbonization and electrification, they contribute to a healthier environment and a more sustainable future.

Interested in hearing more? Reach out to our team at sustainable@priceindustries.com for more information or for help with product selection.

 

Chris Burroughs Chris Burroughs is Product Manager for the Sustainable Systems team at Price. He is based out of Price's Crestridge facility in Suwanee, GA. Click here to connect with him on LinkedIn.

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Topics: Underfloor, Thermal Comfort, HVAC Fundamentals, HVAC, Engineering, Design Engineering

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