Direct Fired Heaters

Direct-Fired Heaters for Industrial and Commercial Use

At Cleanflow, our Direct-Fired Heaters collection offers powerful and efficient heating solutions designed for demanding industrial, commercial, and construction applications.

These heaters provide instant, high-output warmth, making them perfect for outdoor spaces, warehouses, and job sites where reliable heating is essential to keep projects on track.

As a trusted Canadian supplier, Cleanflow ensures that every direct-fired heater from top brands like Heatstar and Flagro is built to withstand harsh conditions while delivering optimal performance and durability.

What is a Direct-Fired Heater?

A direct-fired heater uses an open flame to heat the air. This process is highly efficient, converting nearly 100% of the fuel into heat. The heated air is then circulated by a powerful fan, providing immediate and powerful warmth for large, well-ventilated spaces. Because combustion byproducts are released into the heated area, proper ventilation is essential for safe operation.

Why Choose a Direct-Fired Heater?

Direct-fired heaters are the go-to choice for professionals in construction, agriculture, and emergency services because they offer unmatched efficiency and power. By combusting fuel directly in the air stream, these units achieve nearly 100% thermal efficiency, converting more fuel into usable heat.

High-Efficiency Heating: Delivers immediate and powerful heat, ideal for warming large, open, or well-ventilated spaces quickly.
Fuel Versatility: Available in models that run on propane, natural gas, or diesel, offering flexibility to match the fuel sources on your job site.
Durable & Rugged Design: Built with heavy-duty materials to withstand the tough environments of industrial and construction sites.
Portable & Easy to Operate: Designed with simple ignition systems and mobility features like wheels for quick setup and transport.
Trusted by Professionals: The preferred solution for temporary heating in construction, agriculture, and emergency response across Canada.

Our Top-Selling Direct-Fired Heaters

Explore Cleanflow's curated selection of the best direct-fired heaters from industry-leading brands. We stock models designed for a range of applications, from large-scale construction to outdoor event heating.

Heatstar Direct-Fired Heaters

Heatstar is known for its robust and reliable heating solutions built for North America's toughest job sites.

Heatstar HS4000NG/LP Industrial Heater | 400,000 BTU: This dual-fuel powerhouse delivers 400,000 BTU/hr and is perfect for large-scale heating. It features powerful fans, pneumatic wheels for easy transport, and can connect to an external thermostat for precise temperature control.
Heatstar HS6000DF Forced Air Heater | 610,000 BTU: For massive jobs, the HS6000DF delivers an incredible 610,000 BTUs. It runs on multiple fuels (diesel, kerosene, etc.) and features a 35-gallon tank for up to 8 hours of continuous operation.
Heatstar HS3500DF Forced Air Heater | 360,000 BTU: A versatile multi-fuel heater that provides 360,000 BTUs. With a 27-gallon tank, it can run for 9 hours, making it a reliable choice for long workdays on construction sites.

Flagro Direct-Fired Heaters

Flagro is a Canadian brand with over 40 years of experience building heaters specifically for our winters. They are known for their dual-fuel flexibility and dependable performance.

Flagro F-1500T Construction Heater | 1,500,000 BTU: The ultimate solution for the largest job sites, delivering a massive 1.5 million BTUs. Its dual-fuel (propane/natural gas) capability and stackable design make it a versatile and powerful heating choice.
Flagro F-1000T Construction Heater | 1,000,000 BTU: Perfect for large commercial applications, this direct-fired heater provides 1,000,000 BTUs and features a 100% flame safeguard system, electronic ignition, and thermostat control for safe, easy operation.
Flagro F-400T Construction Heater | 400,000 BTU: A flexible and portable heater with dual-fuel options. Its automatic temperature control, rugged steel frame, and environmentally friendly design make it ideal for mid-sized construction and maintenance jobs.
Flagro THC-355DF Tent Heater | 330,000 BTU: Designed for tent events and enclosed construction sites, this ductable heater offers quiet, thermostatically controlled heat. It can also function as a fresh air circulator.
Flagro THC-175DF Tent Heater | 175,000 BTU: A compact version of the tent heater series, providing 175,000 BTUs of quiet, efficient heat for smaller events and workspaces.

How to Choose the Right Direct-Fired Heater

Selecting the right heater ensures efficiency and safety. Here’s a quick guide to help you decide:

Determine Your Heating Needs (BTU): British Thermal Units (BTU) measure heat output. For a rough estimate, use this rule of thumb:

Open/ventilated areas: 20-30 BTU per sq. ft.
Semi-enclosed workshops: 30-40 BTU per sq. ft.
Enclosed/insulated spaces: 40-50 BTU per sq. ft.
Example: A 2,000 sq. ft. construction site needs approximately 60,000–100,000 BTUs.

Select Your Fuel Type:

Propane/Natural Gas: Clean-burning and versatile. Dual-fuel models from Flagro and Heatstar let you switch between propane tanks and natural gas lines.
Diesel/Kerosene: Ideal for remote sites where other fuel sources aren't available. Multi-fuel models like the Heatstar HS3500DF offer great flexibility.

Consider Your Application:

Large Construction Sites: High-BTU models like the Flagro F-1500T are perfect.
Tent Events: Quiet, ductable models like the Flagro THC series are the best choice.
Warehouses & Workshops: Portable and versatile units like the Heatstar HS4000NG/LP provide reliable heat.

Safety and Ventilation: A Top Priority

Because direct-fired heaters release combustion byproducts into the air, proper ventilation is crucial for safe operation.

Ventilation Rule: Always provide a source of fresh air. A general rule is to have at least 1 square inch of opening for every 1,000 BTU/hr of output.
Carbon Monoxide: Never use a direct-fired heater in unventilated or occupied indoor spaces without a carbon monoxide detector.
Clearances: Keep the heater away from combustible materials as specified by the manufacturer (typically 10-12 feet at the outlet and 3-6 feet on the sides).

Key Applications for Direct-Fired Heaters

Direct-fired heaters are the go-to solution for professionals who need fast, powerful, and portable heat. Their rugged design makes them suitable for a wide range of industries:

Construction: Thawing frozen ground, curing concrete, and keeping work crews warm.
Warehouses & Industrial: Maintaining ambient temperatures in large, open facilities and loading docks.
Agriculture: Heating barns, greenhouses, and equipment storage areas.
Outdoor Events: Providing temporary heat for tents and outdoor venues.
Emergency Heating: Offering a quick and reliable source of warmth during power outages or disasters.

Why Buy from Cleanflow?

As a leading Canadian supplier of industrial equipment, Cleanflow is your trusted partner for heating solutions.

Authorized Canadian Distributor: We offer fast, reliable shipping across Canada from our stocked warehouses.
Expert Technical Support: Our team helps you with sizing, selection, and operational questions to ensure you get the right heater for the job.
CSA-Compliant Models: Shop with confidence knowing our heaters meet Canadian safety and regulatory standards.
Fast Parts Service: We stock a comprehensive inventory of parts to minimize downtime and keep your equipment running.
Volume Pricing: We offer competitive pricing for contractors and businesses needing to equip their entire operation.

Stay warm and productive all winter. Explore our complete collection of Direct-Fired Heaters today!

👉 Save time and avoid manual calculations by using our free BTU calculator tool. Quickly find the ideal heater size for your space here: Cleanflow BTU Calculator

Direct-Fired Heater FAQs

Are direct-fired heaters safe?

Yes. When used correctly. Direct-fired heaters are safe in well-ventilated spaces such as construction sites, warehouses, or outdoor events. Always follow ventilation requirements, clearance guidelines, and use carbon monoxide detectors where appropriate. They are not intended for sealed or residential indoor spaces.

Where are direct-fired heaters commonly used?

They are trusted by professionals in construction, agriculture, and facility maintenance. Common applications include heating construction sites, warehouses, barns, and providing emergency heat for outdoor events.

Are direct-fired heaters safe for indoor use?

They are only safe for indoor use in well-ventilated areas. Proper fresh air intake is required to prevent the buildup of carbon monoxide. They are not suitable for sealed indoor spaces or residential use.

What fuel types are available for direct-fired heaters?

Cleanflow offers direct-fired heaters that run on propane, natural gas, and diesel/kerosene. Dual-fuel and multi-fuel models provide extra flexibility.

Where can I buy high-quality direct-fired heaters in Canada?

You can explore and purchase our full range of CSA-compliant direct-fired heaters directly from Cleanflow. We offer fast shipping across Canada from our Canadian warehouses.

What’s the difference between direct fire and indirect fire heaters?

Direct-Fired Heaters: Burn fuel in the airstream, delivering nearly 100% efficiency and powerful, immediate heat. However, combustion byproducts enter the heated space, so ventilation is essential.

Indirect-Fired Heaters: Use a heat exchanger to keep combustion gases separate from heated air, making them safe for enclosed or occupied spaces. They are less fuel-efficient but provide clean air.