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Direct Fired Enclosed Flame Heater

Direct Fired Heaters

Efficient Vapor Propane or Natural Gas Heating

Direct fired heaters are very much like your typical gas grill or stove top, in which a propane tank or other type of natural gas forces air directly through a flame to heat the air. Direct fired heaters are a great addition to any outdoor party in the fall, winter or early spring, as well as construction sites or disaster relief. What are some of the benefits to direct fire heaters? Here are just a few:

Benefits of Direct Fire Heating

Direct Fired Heater Efficient


First off, the main benefit to using a direct fire heater is the efficiency it provides. As a fuel heater, they convert 100 percent of the fuel being used to heat which lowers fuel consumption and operating costs. This is great if you’re using a heater all day long at a construction site and are trying to keep energy costs down.

Direct Fired Heater Powerful


High amounts of heat (BTU’s) are produced in smaller units when compared to indirect fire heaters. OnSite provides heaters that supply 400,000 BTU’s all the way up to 4,000,000 BTU’s. Now that is power!

Easy to Move Direct Fired heater

Easy to Move

Because they are on wheels and portable, direct fired heaters are pretty easy to set up, move around and turn off when heat is not needed. All it takes is some simple knowledge and common sense to use one of these types of heaters. A few of OnSite’s heaters are also small enough to be moved by one person, requiring less manpower to get heat where you need it.

Direct Fired Low Energy Cost

Lower Energy Cost

Direct fired heaters are lower cost than other types of heaters, meaning you can pump out heat all day long without compromising your budget. If you’re looking for a cost-effective way to boost the temperature in your job site, business or work area, direct fired heaters are the way to go.

Direct Fired Heater Safe for Everyone

Safe for Everyone

Numerous safety features give power to the user, allowing the heaters to stay running without oversight. If you’re throwing a party outdoors, or working a construction site during the winter, the last thing you need to worry about is heater upkeep. With direct fired heaters, even the most novice user can have steady heat flowing all day long.

Direct Fired Heater Low Maintenance Cost

Lower Maintenance Costs

Unlike indirect fired heaters, direct fired heaters are easy to maintain and a simple way to provide heat. Because all it takes is a full propane tank, many times if your heat runs out, the only thing you need is more gas. A quick stop at the gas station or hardware store to refill your tank is all the maintenance that’s required on most direct heater models.

Direct Fired Heater Built in Thermostat

Built in Thermostat

On many direct heater models, a thermostat is displayed to inform the user on what the temperature is. This helps control the climate and temperature, giving the worker the option to turn it off when the temperature reaches the perfect point.

S405 Direct Fired Heater
(400,000 BTU/hr)

The S405 Portable Direct Fired Heater, provided by On Site Companies is the smallest direct fired heating solution that we provide. This portable heater is CSA Approved for unintended use, which makes it easy to keep your job site warm. It is also light enough so only one person is needed for operation. It is designed for use on construction sites and has a thermostat to help conserve fuel.


1801 direct fired heater

1801 Direct Fired Heater
(750,000 BTU/hr)

The 1801 Portable Direct Fired Heater, provided by On Site Companies, will equip your home, business or job site with the heat that you require to be comfortable and efficient. This AGA Certified unit has an air flow switch, burner heat shield and flame safeguard control to ensure safety and efficiency during use. With dual fuel capabilities, you will also have more options on how to run your equipment. The 1801 also has a hi limit switch, panel mounted thermostat and weather sealed control box for optimal usage during the colder months.

Millennium Direct Fired Heater
(1,000,000 BTU/hr)

The Millennium Portable Direct Fired Heater, provided by On Site Companies, can provide your home, business or job site with the heating capabilities that you require. This heater is equipped with a cast iron and stainless steel burner that will work through extreme weather all year round. With flame safeguard control and self-diagnostic L.E.D. lights, you can be easily notified if your unit is not operating at the correct capacity. The Millennium’s light weight design is ductable up to 50 feet to provide heat directly where you need it.

S1505 Direct Fired Heater
(1,500,000 BTU/hr)

The S1505 Portable Direct Fired Heater, provided by On Site Companies, is an efficient direct fired heater that can meet the needs of large job sites or homes. This heater is designed to use less amp draw, which allows it to run on a 15 amp circuit. The updated heater control board also allows you to start the heater with as few as 95 volts and can run stable when voltage drops below 83 volts. With the cold winters in the Mid-West, you can also be assured that this heater can run in temperatures as low as -40F.


s1505 direct fired heater

3050 Direct Fired Heater
(4,000,000 BTU/hr)

The 3050 Portable Direct Fired Heater, provided by On Site Companies, is a great tool for a large and busy job site. The 3050 heater has many safeguards in place to make sure that nothing goes wrong with the equipment. For instance, if the combustion air is interrupted, the 3050 will automatically shut down the system. It also shuts down if the product is being over fired. The heat can also be ducted up to 300 feet from where the equipment is stationed.


Having Some Trouble?

Having trouble with your direct fired heater? Check out some of our tutorial videos that can help you troubleshoot with some common and easy to solve issues you may have come across.