400,000 Btu Indirect-Fired Diesel Heater
400,000 Btu Pro Series Diesel Indirect-Fired Heater

400,000 Btu Pro Series Propane Indirect-Fired Heater


400,000 BTU Multi-Purpose Indirect-Fired Propane Heater for commercial use. Provides temporary heat in structures up to 10,000 sqft (if recirculating) or use in high-temperature applications such as off-gassing or decontamination. It can raise the temperature by 40 degrees in a 44,571 cubic foot space.


  • Additional shipping charges may apply based on your location and dock availability.

Gas Assembly (Required)

Thermostat (Required)

Diameter Discharge (Required)


Add-ons total:



400,000 Btu Pro Series Propane Indirect-Fired Heater Product Features:

  • Simple-to-use
  • Precise Safety and Temperature Controls
  • Includes a Flue Stack 
  • Slim design for easy site mobility and transportation

An indirect-fired propane heater is a common choice for climate control on construction sites, outdoor events, and other spaces requiring temporary heat or decontamination. The heater can be installed for temporary use indoors or outdoors. If installed indoor, the flue must be vented to the outdoors by an HVAC professional. The heater is capable of temporarily heating up to 12,000 square feet with standard 8′ ceiling height, depending on factors such as building envelope, air handling units for air distribution, and other factors. The 400,000 Btu Pro Series delivers the maximum amount of heat, which is crucial for efficient heating of a structure. The heater is equipped with backward incline blowers, which allow for ducting up to 150 feet with extremely quiet delivery of air into the structure. The 400,000 Btu Pro Series comes with your choice of a single 16” diameter discharge or a dual 12” diameter discharge. The heater is able to be recirculated to boost performance in cold weather environments. For sizing decontamination projects, please consult with Thermal Flow technical staff at 833-401-3569 ext 4.

The 400,000 Btu Pro Series is indirect-fired, meaning there is no exposed flame or fumes to be concerned about. You can be assured that fresh, clean air will be delivered into the structure without the fear and concern of flames shooting out of the front of the heater. To further ensure safety, all heaters come standard with an on/off thermostat, which means you do not have to manually adjust the gas flow to control the temperature. The 400,000 Btu Pro Series control box has a supply voltage display to avoid faulty power sources. There are redundant safeties built-in to the heater, including high-temperature limit switch, airflow switch, and flame detection photocell. The body of the heater is made of heavy gauge steel, protecting the components of the heater, and surrounded by steel arms for securing the heater during transport, further safeguarding the heater from accidental damage. The heater has a 4 wheel design providing superior maneuverability. The 400,000 Btu Pro Series Propane Indirect-Fired Heater is simple to operate and turned on by the flip of the switch.

PLEASE NOTE: Power requirements are (1) 15 amp circuit breaker/standard wall outlet. Heater requires a minimum of a 100lb cylinder of propane fuel for proper function, two cylinders are recommended, especially for cold environments.  We recommend the purchase of (1) 16″ High Temperature Duct or (2) 12″ High Temperature Ducts sold in 25′ sections. 

Our professional team has made all things related to heat treatment and airflow our expertise, and we are proud to provide a wide variety of portable heaters. Our staff has completed thousands of treatments, and personally use this equipment in the field. Rest assured, you’re not just purchasing equipment, you’re getting the support of experienced professionals in the industry! Regardless of what kind of portable heater you need, we offer top quality models with all of the accessories needed for optimal performance. We have found products that offer a good balance of both effectiveness, price and are reinforced for high volume use. In addition to heaters, we can help you find the right dehumidifiers, air movers, air scrubbers, and accessories for a variety of needs you may encounter. We have strategic partnerships with manufacturers across the country and can ensure fast delivery of the equipment when and where you need it. Click to see our full line of Climate Control products.

Additional information

Weight470 lbs
Dimensions70 × 29 × 49 in
Diameter Discharge

Dual 12", Single 16"

Thermostat Type:

Standard Thermostat up to 100°F (25' length), High Temp Thermostat up to 170°F (50' length)

Product Specifications

Download Spec Sheet


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